FIELD

[0001] The present disclosure relates to context-awareness in wireless

communication networks and in particular to methods and apparatus for identifying a line of sight (LoS)/non-line of sight (nLoS) state of a user equipment (UE) in wireless communication networks.

BACKGROUND

[0002] The requirements of wireless communication networks and networking hardware are changing dramatically as the demands of the networks change. Not only is there an ever-increasing demand for more bandwidth, the nature of the traffic flowing on the networks is changing. With the demand for video and voice over the network in addition to data, end users and network providers alike are demanding that the network provides services such as quality-of-service (QoS), traffic metering and enhanced security. Context-awareness (e.g., information about location, LoS/nLoS channel condition state, application/device characteristics, etc.) is an important side-information that can help redesign or optimize the way wireless networks/systems/protocols operate.

BRIEF DESCRIPTION OF THE DRAWINGS

[0003] Some examples of circuits, apparatuses and/or methods will be described in the following by way of example only. In this context, reference will be made to the accompanying Figures.

[0004] Fig. 1 illustrates a wireless communication network, in accordance with one embodiment of the disclosure.

[0005] Fig. 2 illustrates a wireless communication network that facilitates determining an LoS state of a user equipment (UE), according to one embodiment of the disclosure.

[0006] Fig. 3 illustrates a wireless communication network that facilitates determining an LoS state of a user equipment (UE), according to one embodiment of the disclosure. [0007] Fig. 4 illustrates a flowchart of an LoS classification algorithm that facilitates determining an LoS state of a user equipment (UE), according to one embodiment of the disclosure.

[0008] Fig. 5a illustrates a flowchart of an LoS ray localization algorithm that facilitates determining a set of candidate points that approximate a location of an LoS ray, according to one embodiment of the disclosure.

[0009] Fig. 5b illustrates a grid of LoS ray locations (in theta and phi), according to one embodiment of the disclosure.

[0010] Fig. 6 illustrates a block diagram of an apparatus for use in a user equipment (UE) in a wireless communication network that facilitates determining an LoS state of a user equipment (UE), according to various embodiments described herein.

[0011] Fig. 7 illustrates a block diagram of an apparatus for use in an Evolved NodeB (eNodeB) in a wireless communication network that facilitates determining an LoS state of a user equipment (UE), according to various embodiments described herein.

[0012] Fig. 8 illustrates a flow chart of a method for a user equipment (UE) in a wireless communication network, according to one embodiment of the disclosure.

[0013] Fig. 9 illustrates a flow chart of a method for an eNodeB in a wireless communication network, according to one embodiment of the disclosure.

[0014] Fig. 1 0 illustrates, example components of a User Equipment (UE) device, for the various embodiments described herein.

DETAILED DESCRIPTION

[0015] In one embodiment of the disclosure, an apparatus for use in a user equipment (UE) of a wireless communication network that facilitates determining a line of sight (LoS) state of the UE with respect to a serving eNodeB is disclosed. The apparatus comprises one or more processors configured to receive a downlink transmission from the serving eNodeB in a plurality of beam directions with respect to the UE. The one or more processors is further configured to determine a plurality of estimation errors based on the received downlink transmission; and identify the LoS state of the UE based on the determined plurality of estimation errors.

[0016] In one embodiment of the disclosure, an apparatus for use in a user equipment (UE) of a wireless communication network that facilitates determining a line of sight (LoS) state of the UE with respect to a serving eNodeB is disclosed. The apparatus comprises one or more processors configured to receive a downlink transmission from the serving eNodeB in a plurality of beam directions with respect to the UE and determine a plurality of estimation errors associated with the downlink transmission for a set of respective beam pair directions, each beam pair direction of the set comprising a first direction and a second, different, direction of the plurality of beam directions and wherein the estimation error for a respective beam pair direction is determined based on a measured signal-to-noise ratio (SNR) of the downlink

transmission at the UE and an array gain of the UE in the respective first direction and the respective second direction. The one or more processors is further configured to identify the LoS state of the UE based on a comparison of an average of the plurality of estimation errors to a predetermined threshold or based on a comparison of a median of the plurality of estimation errors to a predetermined threshold.

[0017] In one embodiment of the disclosure, an apparatus for use in an eNodeB of a wireless communication network that facilitates determining a line of sight (LoS) state of a UE with respect to the eNodeB is disclosed. The apparatus comprises one or more processors configured to receive an uplink transmission from the UE in a plurality of beam directions with respect to the eNodeB. The one or more processors is further configured to determine a plurality of estimation errors based on the received uplink transmission; and identify the LoS state of the UE based on the determined plurality of estimation errors.

[0018] In one embodiment of the disclosure, an apparatus for use in an eNodeB of a wireless communication network that facilitates determining a line of sight (LoS) state of a UE with respect to the eNodeB is disclosed. The apparatus comprises one or more processors configured to receive a uplink transmission from the UE in a plurality of beam directions with respect to the eNodeB and determine a plurality of estimation errors associated with the uplink transmission for a set of respective beam pair directions, each beam pair direction of the set comprising a first direction and a second, different, direction of the plurality of beam directions, and wherein the estimation error for a respective beam pair direction is determined based on a measured signal-to-noise ratio (SNR) of the uplink transmission at the eNodeB and an array gain of the eNodeB in the respective first direction and the respective second direction. The one or more processors is further configured to identify a line of sight (LoS) state of the UE based on a comparison of an average or a median of the plurality of estimation errors to a predetermined threshold.

[0019] The present disclosure will now be described with reference to the attached drawing figures, wherein like reference numerals are used to refer to like elements throughout, and wherein the illustrated structures and devices are not necessarily drawn to scale. As utilized herein, terms "component," "system," "interface," "circuit" and the like are intended to refer to a computer-related entity, hardware, software (e.g., in execution), and/or firmware. For example, a component can be a processor (e.g., a microprocessor, a controller, or other processing device), a process running on a processor, a controller, an object, an executable, a program, a storage device, a computer, a tablet PC and/or a user equipment (e.g., mobile phone, etc.) with a processing device. By way of illustration, an application running on a server and the server can also be a component. One or more components can reside within a process, and a component can be localized on one computer and/or distributed between two or more computers. A set of elements or a set of other components can be described herein, in which the term "set" can be interpreted as "one or more."

[0020] Further, these components can execute from various computer readable storage media having various data structures stored thereon such as with a module, for example. The components can communicate via local and/or remote processes such as in accordance with a signal having one or more data packets (e.g., data from one component interacting with another component in a local system, distributed system, and/or across a network, such as, the Internet, a local area network, a wide area network, or similar network with other systems via the signal).

[0021] As another example, a component can be an apparatus with specific functionality provided by mechanical parts operated by electric or electronic circuitry, in which the electric or electronic circuitry can be operated by a software application or a firmware application executed by one or more processors. The one or more processors can be internal or external to the apparatus and can execute at least a part of the software or firmware application. As yet another example, a component can be an apparatus that provides specific functionality through electronic components without mechanical parts; the electronic components can include one or more processors therein to execute software and/or firmware that confer(s), at least in part, the functionality of the electronic components.

[0022] Use of the word exemplary is intended to present concepts in a concrete fashion. As used in this application, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or". That is, unless specified otherwise, or clear from context, "X employs A or B" is intended to mean any of the natural inclusive permutations. That is, if X employs A; X employs B; or X employs both A and B, then "X employs A or B" is satisfied under any of the foregoing instances. In addition, the articles "a" and "an" as used in this application and the appended claims should generally be construed to mean "one or more" unless specified otherwise or clear from context to be directed to a singular form. Furthermore, to the extent that the terms "including", "includes", "having", "has", "with", or variants thereof are used in either the detailed description and the claims, such terms are intended to be inclusive in a manner similar to the term

"comprising."

[0023] The following detailed description refers to the accompanying drawings. The same reference numbers may be used in different drawings to identify the same or similar elements. In the following description, for purposes of explanation and not limitation, specific details are set forth such as particular structures, architectures, interfaces, techniques, etc. in order to provide a thorough understanding of the various aspects of various embodiments. However, it will be apparent to those skilled in the art having the benefit of the present disclosure that the various aspects of the various embodiments may be practiced in other examples that depart from these specific details. In certain instances, descriptions of well-known devices, circuits, and methods are omitted so as not to obscure the description of the various embodiments with unnecessary detail. [0024] As indicated above, context-awareness is an important side-information that can help redesign or optimize the way wireless networks/systems/protocols operate. One aspect of context-awareness includes, for example, identifying an LoS state of a UE with respect to a base station or eNodeB, which is a primary objective in this disclosure. In some embodiments, identifying an LoS state of a UE comprises identifying if the UE is in view of the eNodeB, without any obstacle between the UE and the eNodeB. A UE (or an eNodeB) that is aware of its LoS/nLoS channel state can use this additional information to optimize its operation in many different scenarios, for example, in order to optimize its RAT (Radio Access Technology) selection algorithm, increase accuracy of its localization algorithm, or optimize its response to a blockage event (e.g., performing cell reselection instead of beam adaptation when the UE is initially in a LoS channel condition). Other scenarios include cyclic prefix configuration based on LoS determination as the delay spread tends to be lower in an LoS

environment.

[0025] Existing methods to identify the LoS state of a device (i.e., a UE) requires training to learn channel characteristics for each particular environment in one instance and in other instance, requires the network/operator to build a data base of expected LoS SNR for the entire environment. In such instances, a UE with information about its location can check its measured SNR with the expected SNR in order to determine its state. However, these methods suffer from many problems including (i) operational cost of running and maintaining a database within an operator's network, (ii) long delay associated with checking the status with the network/database, (iii) the UE/network should potentially have the location information of the UE, and (iv) the UE has to rely on network assistance to obtain its LoS/nLoS channel condition state.

[0026] Therefore, in order to overcome the above issues associated with identifying an LoS state of a device (e.g., UE) in a network, an algorithm, for example, an LoS classification algorithm, that a device (e.g., a UE or an eNodeB) can use in order to identify its LoS channel condition state with high probability and with minimal error is proposed in this disclosure. In massive multiple input, multiple output (MIMO) systems such as mmWave, beam scanning is commonly used to select an appropriate beam for transmission. In such systems, several measurements of a receive beam are available to assess the beam forming/array gain in several directions. This disclosure relies on utilizing such measurements to determine an LoS state of a UE. For example, in this disclosure, the UE or the eNodeB is configured to perform/utilize some measurements based on a downlink transmission or uplink transmission, during their respective receive sector sweep and determine the LoS channel condition, in accordance with the proposed algorithm. In some embodiments, a UE that utilizes this algorithm can immediately identify its LoS state based on a downlink transmission from a serving eNodeB, during each sector sweep of the UE, without relying on any help from the network, without knowing its location, and without knowing the particular channel profile/characteristics of its environment. Similarly, in other embodiments, an eNodeB that utilizes this algorithm can identify the LoS state of a UE with respect to the eNodeB, based on a uplink transmission from the UE, during each sector sweep of the eNodeB.

[0027] Various embodiments described herein utilize the proposed algorithm to determine an LoS state of a UE with respect to an eNodeB, without relying on any help from the network. In particular, in one embodiment, an apparatus for use in a UE that facilitates determining an LoS state of the UE with respect to an eNodeB, in accordance with the LoS classification algorithm is disclosed. In another embodiment, an apparatus for use in an eNodeB that facilitates determining an LoS state of a UE with respect to the eNodeB, in accordance with the LoS classification algorithm is disclosed.

[0028] Fig. 1 illustrates a wireless communication network 100 in accordance with one embodiment of the disclosure. The wireless communication network 100 comprises an eNodeB 102 and a user equipment (UE) 104. In some embodiments, the wireless communication network 100 facilitates determining a line of sight (LoS) state of the UE 104 with respect to the eNodeB 102 with high probability and minimal error. In some embodiments, the LoS state of the UE 104 can be determined at the UE 1 04 during a receive sector sweep of the UE 104. In such embodiments, the LoS state of the UE 104 is determined based on receiving a downlink transmission 106 associated with the eNodeB 1 02 at the UE 104. In such embodiments, the UE 104 can be configured to receive the downlink transmission 106 in a plurality of beam directions. In some embodiments, the plurality of beam directions is associated with a plurality of directions in which an antenna array associated with the UE 104 is pointed to. In some embodiments, an LoS state of the UE 104 is determined based on determining a plurality of estimation errors associated with the downlink transmission 106, at the UE 104, in accordance with a predetermined LoS classification algorithm, the details of which are given in embodiments below.

[0029] Alternately, in other embodiments, the LoS state of the UE 104 can be determined at the eNodeB 1 02 during a receive sector sweep of the eNodeB 104. In such embodiments, the LoS state of the UE 104 is determined based on receiving a uplink transmission 108 associated with the UE 104 at the eNodeB 102. In such embodiments, the eNodeB 102 can be configured to receive the uplink transmission 108 in a plurality of beam directions. In some embodiments, the plurality of beam directions is associated with a plurality of directions in which an antenna array associated with the eNodeB 102 is pointed to. In some embodiments, an LoS state of the UE 104 is determined based on determining a plurality of estimation errors associated with the uplink transmission 108, at the eNodeB 102, in accordance with the predetermined LoS classification algorithm.

[0030] Fig. 2 illustrates a wireless communication network 200 that facilitates determining an LoS state of a user equipment (UE), according to one embodiment of the disclosure. The wireless communication network 200 comprises an eNodeB 202 and a UE 204. In this particular embodiment, the LoS state of the UE 204 is determined at the UE 204, during a receive sector sweep (RXSS) of the UE 204. However, in other embodiments, the LoS state of the UE 204 can be determined at the eNodeB 202, during a receive sector sweep of the eNodeB 202. In some embodiments, it is assumed that when the UE 204 performs the RXSS, the eNodeB 202 does not change its beam direction or the eNodeB 202 transmits in a pseudo-omni directional/wide beam manner. In some embodiments, the receive sector sweep of the UE 204 can be associated with a secondary synchronization signal (SSS), where the eNodeB 202 transmits in a pseudo-omni directional/wide beam manner and the UE 204 performs a receive sector sweep (RXSS).

[0031] During the receive sector sweep of the UE 204, in some embodiments, the UE 204 is configured to receive the downlink transmission 206a transmitted from the eNodeB 202, in a plurality of beam directions K1 , K2...KN. In some embodiments, the plurality of beam directions K1 , K2...KN is associated with a plurality of directions in which an antenna array associated with the UE 204 is pointed to. In some embodiments, upon receiving the downlink transmission 206a, the UE 204 is configured to determine an LoS state of the UE 204, in accordance with an LoS classification algorithm, the details of which are given in an embodiment below.

[0032] In some embodiments, a measured signal-to-noise ratio (SNR) of the downlink transmission 206a at the UE 204 is given by,

Measured SNR = Pt + Gt + Gr - PL - NF (1 ) where Pt is the eNodeB transmit power, Gt is the overall transmit beamforming gain (including the channel effect) at the eNodeB, Gr is the overall receive beamforming gain (including the channel effect) at the UE, PL is the path loss and NF is the noise figure at the UE. In some embodiments, the Pt, Gt, PL and NF are fixed when the UE 204 performs the RXSS and the only varying term across sector sweeps is Gr (based on the direction of the antenna array of the UE 204).

[0033] An idea that is leveraged in the design of the LoS classification algorithm, that is utilized to determine an LoS state of a UE (e.g., the UE 204) is that, when a channel between the eNodeB 202 and the UE 204 is LoS, it can be assumed that a power of an LoS component of the downlink transmission 206a from the eNodeB 202 typically dominates all other non-LoS (nLoS) components at the UE 204. Therefore in such embodiments, when the channel between the eNodeB 202 and the UE 204 is LoS, a difference between Gr(k) (when UE 204 is pointing towards direction k) and Gr(k') (when UE is pointing towards direction k') is roughly equal to 2 ^* (ArrayGain(theta, phi, k) - ArrayGain(theta, phi, k')), in which theta and phi are the azimuth and zenith angle of arrival, respectively, of the LoS ray (i.e., the LoS ray of the downlink transmission 206a) at the UE 204.

That is,

Gr(k) - Gr(k') ^« 2 ^* (ArrayGain(theta, phi, k) - ArrayGain(theta, phi, k')) (2)

In some embodiments, k and k' defines a beam pair direction that includes two different directions the UE 204 points to during RXSS and comprises directions from K1 ...KN. [0034] In some embodiments, the ArrayGain(theta, phi, k) is the UE (i.e., the UE 204) array gain for the downlink transmission 206a, when the UE 204 is pointing towards direction k, and the ArrayGain(theta, phi, k') is the UE (i.e., the UE 204) array gain for the downlink transmission 206a, when the UE 204 is pointing towards direction k'. In some embodiments, the azimuth and zenith angle of arrival of the LoS ray of the downlink transmission 206a is determined at the UE 204, in accordance with an LoS ray localization algorithm, the details of which are given in an embodiment below. In some embodiments, determining the azimuth and zenith angle of arrival of the LoS ray of the downlink transmission 206a at the UE 204 comprises determining a set of candidate points (theta-i, phi-i) for i = 1 to n, that approximates the location of the LoS ray of the downlink transmission 206a, each candidate point of the set identified by its azimuth and zenith angle of arrival, at the UE 204, in accordance with an LoS ray localization algorithm.

[0035] From equation (1 ), it can be seen that Gr is proportional to the measured SNR, as Gr is the only varying term in equation (1 ). Therefore, in some embodiments, the difference between Gr(k) and Gr(k') is equal to a difference between measured SNR(k) (when the UE 204 is pointing towards direction k) and measured SNR(k') (when the UE 204 is pointing towards direction k'). Therefore, when the channel is LoS, the equation (2) can be written as:

Measured SNR(k) - Measured SNR(k') ^« 2 ^* (ArrayGain(theta,phi,k) - ArrayGain(theta,phi,k')) (3) where the measured SNR(k), measured SNR(k'), ArrayGain(theta,phi,k) and

ArrayGain(theta,phi,k') are measured in dB and where k and k' are two different directions the UE 204 points to during RXSS and comprises directions from K1 ...KN, and theta and phi are the Azimuth and Zenith Angle of Arrival, respectively, of the LoS ray (i.e., the LoS ray of the downlink transmission 206a) at the UE 204.

[0036] In some embodiments, equation (3) can be converted into absolute values (instead of dB), and is re-written as provided below:

Measured SNR(k)/Measured SNR(k') ~

(ArrayGain(theta,phi,k)/ArrayGain(theta,phi,k')) ^A 2 (4) The array gain in equations (3) and (4) can be calculated using standard predefined relations, depending on the type of the antenna array at the UE 204.

[0037] In some embodiments, the relation Measured SNR(k)/Measured SNR(k') is defined as given below:

Ratio-Measured SNR(k,k') = Measured SNR(k)/Measured SNR(k') (5) And

Ratio-Calc Arraygain (theta, phi, k, k') =

(ArrayGain(theta,phi,k)/ArrayGain(theta,phi,k')) ^A 2 (6)

[0038] Based on equations (5) and (6), an estimation error is defined, which is given below:

Estimation error (k,k') = | Ratio-Measured SNR(k,k') - Ratio-Calc Arraygain (theta, phi, k, k') I (7) where k and k' comprise a beam pair direction.

[0039] In some embodiments, a plurality of estimation errors is determined for a plurality of respective beam pair directions (k, k') and an LoS state of the UE (e.g., the UE 204) is determined based on the plurality of estimation errors in accordance with the LoS classification algorithm, the details of which are given in an embodiment below. In some embodiments, the set of beam pair directions (k, k') are also determined, in accordance with the LoS classification algorithm. In some embodiments, each beam pair direction (k, k') of the set comprises a first direction and a second, different direction of the plurality of beam directions K1 ...KN. In some embodiments, the plurality of estimation errors is determined for a predetermined number (e.g., β) of beam pair directions, in order to determine the LoS state of the UE 204.

[0040] In some embodiments, the plurality of estimation errors is determined for one or more candidate points of the set of candidate points (theta-i, phi-i), for i = 1 to n, each candidate point comprising the azimuth and zenith angle of arrival of the LoS ray of the downlink transmission 206a. For example, in some embodiments, the UE 204 is configured to determine the plurality of estimation errors successively for each of the candidate points of the set, until the LoS state of the UE 204 is identified (in accordance with the LoS classification algorithm) based on the determined plurality of estimation errors for a candidate point of the set or until all the candidate points of the set are exhausted. In some embodiments, the LoS state of the UE 304 is determined when an average or median of the plurality of estimation errors across the predetermined number of beam pair directions for a candidate point of the set, is less than or equal to a predetermined threshold.

[0041] Upon determining if the UE 204 is in an LoS state or a non-LoS state, the UE 204 is further configured to provide a feedback message 206b comprising the feedback information on the LoS/n-LoS state of the UE 204 to the eNodeB 202. In some embodiments, the UE 204 is configured to generate a dedicated UE feedback message 206b to be provided to the eNodeB 202, comprising information on the LoS/n-LoS state of the UE 204. However, in other embodiments, information on the LoS/n-LoS state of the UE 204 can be fed back to the eNodeB 202 by adding a one bit flag in a channel quality indicator (CQI) feedback message or a sector sweep/beam-training feedback message comprising the UE feedback message 206b. In some embodiments, the eNodeB 202 may use the information on the LoS/n-LoS state of the UE 204 to trigger handover or scheduling decision. However, in other embodiments, the eNodeB 202 can use the information on the LoS/n-LoS state of the UE 204 for other purposes.

[0042] Fig. 3 illustrates a wireless communication network 300 that facilitates determining an LoS state of a user equipment (UE), according to one embodiment of the disclosure. The wireless communication network 300 comprises an eNodeB 302 and a UE 304. In this particular embodiment, the LoS state of the UE 304 is determined at the eNodeB 302, during a receive sector sweep (RXSS) of the eNodeB 302.

However, in other embodiments, the LoS state of the UE 304 can be determined at the UE 304, as explained above in Fig. 2. In some embodiments, it is assumed that when the eNodeB 302 performs the RXSS, the UE 304 does not change its beam direction or the UE 304 transmits in a pseudo-omni directional/wide beam manner.

[0043] During the receive sector sweep of the eNodeB 302, in some embodiments, the eNodeB 302 is configured to receive the uplink transmission 306a transmitted from the UE 304, in a plurality of beam directions K1 , K2...KN. In some embodiments, the plurality of beam directions is associated with a plurality of directions in which an antenna array associated with the eNodeB 302 is pointed to. Upon receiving the uplink transmission 306a, in some embodiments, the eNodeB 302 is configured to determine an LoS state of the UE 304 based on the uplink transmission 306a, in accordance with an LoS classification algorithm, the details of which are given in an embodiment below.

[0044] In some embodiments, a measured signal-to-noise ratio (SNR) of the uplink transmission 306a at the eNodeB 302 is given by,

Measured SNR = Pt + Gt + Gr - PL - NF (8)

Where Pt is the UE transmit power, Gt is the overall transmit beamforming gain

(including the channel effect) at the UE, Gr is the overall receive beamforming gain (including the channel effect) at the eNodeB, PL is the path loss and NF is the noise figure at the eNodeB. In some embodiments, the Pt, Gt, PL and NF are fixed when the eNodeB 302 performs the RXSS and the only varying term across sector sweeps is Gr (based on the direction of the antenna array of the eNodeB 302).

[0045] A key idea that is leveraged in the design of the LoS classification algorithm, that is utilized to determine an LoS state of a UE (e.g., the UE 304) is that, when a channel between the eNodeB 302 and the UE 304 is LoS, it can be assumed that a power of an LoS ray of the uplink transmission 306a from the UE 304 typically dominates all other non-LoS (nLoS) components at the eNodeB 302. Therefore, in such embodiments, when the channel between the eNodeB 302 and the UE 304 is LoS, a difference between Gr(k) (when eNodeB 302 is pointing towards direction k) and Gr(k') (when eNodeB 302 is pointing towards direction k') is roughly equal to

2 ^* (ArrayGain(theta, phi, k) - ArrayGain(theta, phi, k')), in which theta and phi are the azimuth and zenith angle of arrival, respectively, of the LoS ray (i.e., the LoS ray of the uplink transmission 306a) at the eNodeB 302.

That is,

Gr(k) - Gr(k') ^« 2 ^* (ArrayGain(theta, phi, k) - ArrayGain(theta, phi, k')) In some embodiments, k and k' defines a beam pair direction that includes two different directions the eNodeB 302 points to during RXSS and comprises directions from K1 ...KN.

[0046] In some embodiments, the ArrayGain(theta, phi, k) is the eNodeB (i.e., the eNodeB 302) array gain for the uplink transmission 306a, when the eNodeB 302 is pointing towards direction k, and the ArrayGain(theta, phi, k') is the eNodeB (i.e., the eNodeB 302) array gain for the uplink transmission 306a, when the eNodeB 302 is pointing towards direction k'. In some embodiments, the azimuth and zenith angle of arrival of the LoS ray of the uplink transmission 306a is determined at the eNodeB 302, in accordance with an LoS ray localization algorithm, the details of which are given in an embodiment below. In some embodiments, determining the azimuth and zenith angle of arrival of the LoS ray of the uplink transmission 306a at the eNodeB 302 comprises determining a set of candidate points (theta-i, phi-i), for i = 1 to n, that approximates the location of the LoS ray of the uplink transmission 306a, each candidate point i of the set identified by its azimuth and zenith angle of arrival, at the eNodeB 302, in accordance with the LoS ray localization algorithm.

[0047] From equation (8), it can be seen that Gr is proportional to the measured SNR, as Gr is the only varying term in equation (8). Therefore, in some embodiments, the difference between Gr(k) and Gr(k') is equal to a difference between measured SNR(k) (when the eNodeB 302 is pointing towards direction k) and measured SNR(k') (when the eNodeB 302 is pointing towards direction k'). Therefore, when the channel is LoS, the equation (9) can be written as:

Measured SNR(k) - Measured SNR(k') ^« 2 ^* (ArrayGain(theta,phi,k) - ArrayGain(theta,phi,k')) (10) where the measured SNR(k), measured SNR(k'), ArrayGain(theta,phi,k) and ArrayGain(theta,phi,k') are measured in dB and where k and k' are two different directions the eNodeB 302 points to during RXSS and comprises directions from K1 ...KN, and theta and phi are the azimuth and zenith angle of arrival of the LoS ray (i.e., the LoS ray of the uplink transmission 306a) at the eNodeB 302. [0048] In some embodiments, equation (10) can be converted into absolute values (instead of dB), and is re-written as provided below:

Measured SNR(k)/Measured SNR(k') ~

(ArrayGain(theta,phi,k)/ArrayGain(theta,phi,k')) ^A 2 (1 1 )

The array gain in equations (10) and (1 1 ) can be calculated using standard predefined relations, depending on the type of antenna array at the eNodeB 302.

[0049] In some embodiments, the relation Measured SNR(k)/Measured SNR(k') is defined as given below:

Ratio-Measured SNR(k,k') = Measured SNR(k)/Measured SNR(k') (12)

And

Ratio-Calc Arraygain (theta, phi, k, k') =

(ArrayGain(theta,phi,k)/ArrayGain(theta,phi,k')) ^A 2 (13)

Based on equations (12) and (13), an estimation error is defined, which is given below:

Estimation error (k,k') = | Ratio-Measured SNR(k,k') - Ratio-Calc Arraygain (theta, phi, k, k') | (14)

Where k and k' comprise a beam pair direction.

[0050] In some embodiments, a plurality of estimation errors is determined for a set of respective beam pair directions (k, k') and an LoS state of the UE (e.g., the UE 304) is determined based on the plurality of estimation errors in accordance with the LoS classification algorithm, the details of which are given in an embodiment below. In some embodiments, the set of beam pair directions (k, k') are also determined, in accordance with the LoS classification algorithm. In some embodiments, each beam pair direction (k, k') of the set comprises a first direction and a second, different direction of the plurality of beam directions K1 ...KN. In some embodiments, the plurality of estimation errors is determined for a predetermined number (e.g., β) of beam pair directions, in order to determine the LoS state of the UE 304. [0051] In some embodiments, the plurality of estimation errors is determined for one or more candidate points of the set of candidate points (theta-i, phi-i), for i = 1 to n, each candidate point comprising the azimuth and zenith angle of arrival of the LoS ray of the uplink transmission 306a. For example, in some embodiments, the eNodeB 302 is configured to determine the plurality of estimation errors successively for each of the candidate points i of the set, until the LoS state of the UE 204 is identified (in

accordance with the LoS classification algorithm) based on the determined plurality of estimation errors for a candidate point of the set or until all the candidate points of the set are exhausted. In some embodiments, the LoS state of the UE 304 is determined when, for a given candidate point i, an average or median of the plurality of estimation errors across the predetermined number of beam pair directions is less than or equal to a predetermined threshold.

[0052] Upon determining if the UE 304 is in an LoS state or a non-LoS state, in some embodiments, the eNodeB 302 is configured to provide feedback information on the LoS/n-LoS state of the UE 304 to the UE 304. In some embodiments, upon determining information on the LoS/n-LoS state of the UE 304, the eNodeB 302 provides an LoS indicator message 306b that provides an indication to the UE 304 about the availability of the LoS information at the eNodeB 302. Based on the LoS indicator, the UE 304 can choose not to determine its LoS/n-LoS state at the UE 302. In some embodiments, the eNodeB 302 may use the information on the LoS/n-LoS state of the UE 304 to trigger handover or scheduling decision. However, in other embodiments, the eNodeB 302 can use the information on the LoS/n-LoS state of the UE 304 for other purposes.

[0053] Fig. 4 illustrates a flowchart of an LoS classification algorithm 400 that facilitates determining an LoS state of a user equipment (UE), according to one embodiment of the disclosure. The algorithm 400 can be implemented within the UE 204 in Fig. 2 or within the eNodeB 302 in Fig. 3. At 402, a set of candidate points, for example, (theta-i, phi-i), for i = 1 to n, that approximate a location of a LoS ray is determined. In one embodiment, the LoS ray comprises the downlink transmission 206a in Fig. 2 and the set of candidate points is determined at the UE 204 based on the downlink transmission 206a. Alternately, in another embodiment, the LoS ray comprises the uplink transmission 306a in Fig. 3 and the set of candidate points is determined at the eNodeB 302 based on the uplink transmission 306a. In some embodiments, the set of candidate points (theta-i, phi-i), for i = 1 to n, is determined in accordance with an LoS ray localization algorithm, the details of which are given in an embodiment below.

[0054] At 404, a set of beam pair directions (k, k') is determined. In one

embodiment, for example, with respect to Fig. 2, each beam pair direction (k, k') of the set of beam pair directions comprises a first direction and a second, different direction of the plurality of beam directions K1 to KN of the downlink transmission 206a at the UE 204. Alternately, in another embodiment, for example, with respect to Fig. 3, each beam pair direction (k, k') of the set of beam pair directions comprises a first direction and a second, different direction of the plurality of beam directions K1 to KN of the uplink transmission 306a at the eNodeB 302. In some embodiments, the beam pair directions k and k' are chosen such that a ratio of the measured SNR of the LoS ray in direction k and the measured SNR of the LoS ray in the direction k', for example, Ratio- measured SNR (k,k'), is less than a, where a is predetermined SNR threshold. In some embodiments, k denotes a beam direction that achieves a maximum signal-to-noise ratio (SNR) and k' denotes any other direction in a sector sweep, that satisfies the above condition. However, in other embodiments, k and k' can be any direction from the plurality of beam directions K1 to KN, that satisfies the above condition. In some embodiments, the set of beam pair directions (k,k') should at least comprise a predetermined number (e.g., β) of beam pair directions, in order to facilitate to determine an LoS state of a UE.

[0055] At 406, a candidate point i from the set of candidate points (theta-i, phi-i), for i = 1 to n, is chosen. At 408, for the candidate point i, a plurality of estimation errors is determined corresponding to the set of beam pair directions (k, k'). In one

embodiment, for example, with respect to Fig. 2, the plurality of estimation errors is determined based on equation (7). Alternately, in another embodiment, for example, with respect to Fig. 3, the plurality of estimation errors is determined based on equation (14). At 410, an average or median of the plurality of estimation errors is determined. At 412, a determination if the average or median of the plurality of estimation errors is less than or equal to a predetermined threshold, for example, μ is performed. If yes at 41 2, the algorithm proceeds to 414, where a determination that the UE is in LoS state is made. If No at 412, the algorithm proceeds to 416, where a determination on the existence of other candidate points i in the set of candidate points is performed. If No at 41 6, the algorithm proceeds to 418, where a determination that the UE is in a nLoS state is made. If yes at 416, the algorithm proceeds to 420, where a next candidate point i of the set of candidate points is chosen. In some embodiments, the plurality of estimation errors is successively determined for each of the candidate points i = 1 to n of the set of candidate points, until an LoS state of the UE is determined at 414 or all the candidate points are exhausted (i.e., No at 416).

[0056] Fig. 5a illustrates a flowchart of an LoS ray localization algorithm 500 that facilitates determining a set of candidate points that approximate a location of an LoS ray, according to one embodiment of the disclosure. The algorithm 500 can be implemented within the UE 204 in Fig. 2 or within the eNodeB 302 in Fig. 3. In some embodiments, the algorithm 500 is implemented in the UE 204 in Fig. 2 or within the eNodeB 302 in Fig. 3, in order to determine the set of candidate points in the algorithm 400 (e.g., at 402) above. In one embodiment, for example, with respect to Fig. 2, the algorithm is implemented within the UE 204, in order to determine the set of candidate points that approximate the location of the LoS ray of the downlink transmission 206a. Alternately, in another embodiment, for example, with respect to Fig. 3, the algorithm is implemented within the eNodeB 302, in order to determine the set of candidate points that approximate the location of the LoS ray of the uplink transmission 306a. At 502, a plurality of LoS ray locations (theta-j, phi-j), for j = 1 to x, that approximate the location of an LoS ray (e.g., the LoS ray of the downlink transmission 206a in Fig. 2 or the LoS ray of the uplink transmission 306a in Fig. 3) is determined. In some embodiments, the plurality of LoS ray locations is determined based on constructing a grid in theta and phi, in a coverage area of a maximum signal-to-noise ratio (SNR) achieving beam direction of the LoS ray, as illustrated in Fig. 5b.

[0057] At 504, a beam pair direction (k, k") is determined. In some embodiments, k denotes a maximum SNR achieving beam direction of the LoS ray (e.g., the downlink transmission 206a in Fig. 2 or the uplink transmission 306a in Fig. 3) and k" is a reference beam direction that denote any other direction not equal to k, such that a measured SNR ratio comprising a ratio of the measured SNR of the LoS ray in k direction and the measured SNR in the k" direction, for example, Ratio-measured SNR, is less than or equal to a, where a is a predetermined LoS threshold. In some embodiments, the direction k and k" are chosen such that k" is not a neighboring direction of k (i.e., the beam coverage area of k and k" do not overlap). In some embodiments, when the LoS ray comprises the downlink transmission 206a, k and k" belong to the plurality of beam directions K1 to KN in Fig. 2. Whereas, in other embodiments, when the LoS ray comprises the uplink transmission 306a, k and k" belong to the plurality of beam directions K1 to KN in Fig. 3.

[0058] At 506, a LoS ray location (theta-j, phi-j) from the plurality of LoS ray locations is chosen. At 508, a calculated array gain ratio comprising a ratio of a calculated array gain of the LoS ray in the maximum SNR achieving beam direction k and the reference beam direction k", for the LoS ray location (theta-j, phi-j) is determined. In some embodiments, the ratio of the calculated array gain of the LoS ray can be computed, in accordance with equation (6) or equation (13) above. At 510, measured SNR ratio comprising a ratio of a measured SNR of the LoS ray in the maximum SNR achieving beam direction and the reference beam direction is determined. In some embodiments, the ratio of the measured SNR of the LoS ray is determined, in accordance with equation (5) or equation (12) above. At 512, an error value corresponding to a difference between the ratio of the calculated array gain of the LoS ray (determined at 506) and the ratio of the measured SNR of the LoS ray (determined at 508) is determined.

[0059] At 514, a determination if the error value (determined at 512) is less than or equal to μ', where μ' is a predetermined candidate threshold, is made. If yes at 514, the chosen LoS ray location j is determined as a candidate point at 516. If No at 514, then the chosen LoS ray location j is determined as a non-candidate point 518. After 516 or 51 8, the algorithm 500 further proceeds to 520, where a determination of the existence of other LoS ray locations j in the grid is made. If yes at 520, a next LoS ray location is chosen from the plurality of LoS ray locations at 522. In some embodiments, the algorithm 500 proceeds to determine all the candidate points from the plurality of LoS ray locations, until all the LoS ray locations are exhausted (i.e., No at 520), when the algorithm 500 comes to an end at 524.

[0060] Fig. 6 illustrates a block diagram of an apparatus 600 for use in a user equipment (UE) in a wireless communication network that facilitates determining an LoS state of a user equipment (UE), according to various embodiments described herein. The apparatus 600 is described herein with reference to the UE 204 in the wireless communication network 200 in Fig. 2, the LoS classification algorithm 400 in Fig. 4 and the LoS ray localization algorithm 500 in Fig. 5a. The apparatus 600 includes a receiver circuit 61 0, a processing circuit 630, and a transmitter circuit 620. Further, in some embodiments, the apparatus 600 comprises a memory circuit 640 coupled to the processing circuit 630. In some embodiments, the memory circuit 640 comprises a computer readable storage device that includes instructions to be executed by the processor 630. In some embodiments, the memory circuit 640 can be an independent circuit and in other embodiments, the memory circuit 640 can be integrated on chip with the processor 630. Alternately, in other embodiments, the instructions to be executed by the processor 630 can be stored on a non-transitory storage medium like CR-ROM, flash drive etc., and can be downloaded to the memory circuit 640 for execution. Each of the receiver circuit 610 and the transmitter circuit 620 are configured to be coupled to one or more antennas, which can be the same or different antenna(s). In some embodiments, the receiver circuit 610 and transmitter circuit 620 can have one or more components in common, and both can be included within a transceiver circuit, while in other aspects they are not. In various embodiments, the apparatus 600 can be included within a UE, for example, with apparatus 600 (or portions thereof) within a receiver and transmitter or a transceiver circuit of a UE.

[0061] During a receive sector sweep of the UE (e.g., the UE 204 in Fig. 2), the processing circuit 630 is configured to receive a downlink transmission (e.g., the downlink transmission 206a in Fig. 2), via the receiver circuit 610, in a plurality of beam directions, for example, K1 , K2...KN in Fig. 2. In some embodiments, the plurality of beam directions corresponds to a plurality of directions in which an antenna array associated with the UE or the receiver circuit 610 is pointed to during the receive sector sweep of the UE (e.g., the UE 204 in Fig. 2). Upon receiving the downlink transmission, processing circuit 630 is configured to identify an LoS state of the UE (e.g., the UE 204 in Fig. 2), by implementing the LoS classification algorithm as explained above with respect to Fig. 4. In some embodiments, the LoS classification algorithm 400 is implemented in the processing circuit 630 based on instructions stored in the memory circuit 640. For example, upon receiving the downlink transmission, in some

embodiments, the processing circuit 630 is configured to determine a set of candidate points i (e.g., the candidate points (theta-i, phi-i) in Fig. 4) that approximate the location of the LoS ray (i.e., the LoS ray of the downlink transmission 206a in Fig. 2).

[0062] In some embodiments, the set of candidate points i are determined at the processing circuit 630, based on the downlink transmission (i.e., the downlink transmission 206a in Fig. 2), in accordance with the LoS ray localization algorithm 500 explained above in Fig. 5a. In some embodiments, the instructions for implementing the LoS ray localization algorithm 500 is stored within the memory circuit 640. The processing circuit 630 is further configured to determine a set of beam pair directions (k, k') from the plurality of beam directions of the downlink transmission, in order to estimate a plurality of estimation errors associated therewith. In some embodiments, the set of beam pair directions are determined at the processing circuit 630 as explained above with respect to the LoS classification algorithm 400 in Fig. 4. For a given candidate point i, the processing circuit 630 is configured to determine a plurality of estimation errors corresponding to the set of beam pair directions (k, k'). In some embodiments, the plurality of estimation errors is determined at the processing circuit 630 in accordance with the equation (7) above. In some embodiments, the memory circuit 640 is further configured to store the set of candidate points i, the set of beam pair directions (k,k') and the plurality of estimation errors determined at the processing circuit 630.

[0063] In some embodiments, the LoS state of the UE (e.g., the UE 204 in Fig. 2) is identified when a median or average of the plurality of estimation errors determined at the processing circuit 630 for given candidate point i meets a predetermined condition as explained above with respect to the LoS classification algorithm 400 in Fig. 4. In some embodiments, the processing circuit 630 is configured to determine the plurality of estimation errors for each of the set of the candidate points i, until the LoS state of the UE (i.e., the UE 204 in Fig. 2) is identified based on the determined plurality of estimation errors for a candidate point i of the set or until all the candidate points of the set are exhausted. Upon determining if the UE is in an LoS state or a non-LoS state, the processing circuit is further configured to provide a feedback message (e.g., the feedback message 206b in Fig. 2) to a serving eNodeB (e.g., the eNodeB 202 in Fig. 2), via the transmitter circuit 620. In some embodiments, the feedback message comprises information on the LoS/n-LoS state of the UE (e.g., the UE 204 in Fig. 2). [0064] In some embodiments, in order to implement the LoS ray localization algorithm 500 (to determine the set of candidate points i), the processing circuit 630 is configured to construct a grid in theta and phi, in a coverage area of a maximum signal- to-noise ratio (SNR) achieving beam direction corresponding to the downlink

transmission 206a in Fig. 2). In some embodiments, the grid corresponds to a plurality of LoS ray locations (theta-j, phi-j), for j = 1 to x, that approximate the location of LoS ray (i.e., the LoS ray of the downlink transmission 206a). The processing circuit 630 is further configured to determine a beam pair direction (k, k") that satisfies a

predetermined condition, as explained above with respect to the LoS ray localization algorithm 500 in Fig. 5a. For each LoS ray location j and the beam pair direction (k, k"), the processing circuit 630 is configured to determine an error value corresponding to a difference between the ratio of the calculated array gain of the LoS ray (i.e., the LoS ray of the downlink transmission 206a) and the ratio of the measured SNR of the beam pair direction (k, k"). In some embodiments, an LoS ray location j is identified as a candidate point i, at the processing circuit 630, when the error value satisfies a predetermined condition as explained above with respect to the LoS ray localization algorithm 500 in Fig. 5a.

[0065] Fig. 7 illustrates a block diagram of an apparatus 700 for use in an Evolved

NodeB (eNodeB) in a wireless communication network that facilitates determining an

LoS state of a user equipment (UE), according to various embodiments described herein. The apparatus is described herein with reference to the eNodeB 302 in the wireless communication network 300 in Fig. 3, the LoS classification algorithm 400 in

Fig. 4 and the LoS ray localization algorithm 500 in Fig.5a. The apparatus 700 can include a transmitter circuit 71 0, a receiver circuit 720 and a processing circuit 730.

Each of the receiver circuit 720 and the transmitter circuit 710 are configured to be coupled to one or more antennas, which can be the same or different antenna(s).

Further, in some embodiments, the apparatus comprises a memory circuit 740 coupled to the processor 730. In some embodiments, the memory circuit 740 comprises a computer readable storage device that includes instructions to be executed by the processor 730. In some embodiments, the memory circuit 740 can be an independent circuit and in other embodiments, the memory circuit 740 can be integrated on chip with the processor 730. Alternately, in other embodiments, the instructions to be executed by the processor 730 can be stored on a non-transitory storage medium like CR-ROM, flash drive etc., and can be downloaded to the memory circuit 740 for execution. In some embodiments, the receiver circuit 720 and the transmitter circuit 71 0 can have one or more components in common, and both can be included within a transceiver circuit, while in other aspects they are not. In various embodiments, the apparatus 700 can be included within an Evolved Universal Terrestrial Radio Access Network (E- UTRAN) Node B (Evolved NodeB, eNodeB, or eNB).

[0066] During a receive sector sweep of the eNodeB (e.g., the eNodeB 302 in Fig. 3), the processing circuit 730 is configured to receive a uplink transmission (e.g., the uplink transmission 306a in Fig. 3), via the receiver circuit 710, in a plurality of beam directions, for example, K1 , K2...KN in Fig. 3. In some embodiments, the plurality of beam directions corresponds to a plurality of directions in which an antenna array associated with the eNodeB or the receiver circuit 710 is pointed to during the receive sector sweep of the eNodeB (e.g., the eNodeB 302 in Fig. 3). Upon receiving the uplink transmission, processing circuit 730 is configured to identify an LoS state of the UE (e.g., the UE 304 in Fig. 3), by implementing the LoS classification algorithm as explained above with respect to Fig. 4. In some embodiments, the LoS classification algorithm 400 is implemented in the processing circuit 730 based on instructions stored in the memory circuit 740. For example, upon receiving the uplink transmission, in some embodiments, the processing circuit 730 is configured to determine a set of candidate points i (e.g., the candidate points (theta-i, phi-i) in Fig. 4) that approximate the location of the LoS ray (i.e., the LoS ray of the uplink transmission 306a in Fig. 3).

[0067] In some embodiments, the set of candidate points i are determined at the processing circuit 730, based on the uplink transmission (i.e., the uplink transmission 306a in Fig. 3), in accordance with the LoS ray localization algorithm 500 explained above in Fig. 5a. In some embodiments, the instructions for implementing the LoS ray localization algorithm 500 are stored within the memory circuit 740. The processing circuit 730 is further configured to determine a set of beam pair directions (k, k') from the plurality of beam pair directions of the uplink transmission, in order to estimate a plurality of estimation errors associated therewith. In some embodiments, the set of beam pair directions are determined at the processing circuit 730 as explained above with respect to the LoS classification algorithm 400 in Fig. 4. For a given candidate point i, the processing circuit 730 is configured to determine a plurality of estimation errors corresponding to the set of beam pair directions (k, k'). In some embodiments, the plurality of estimation errors is determined at the processing circuit 730 in accordance with the equation (14). In some embodiments, the memory circuit 740 is further configured to store the set of candidate points i, the set of beam pair directions (k,k') and the plurality of estimation errors determined at the processing circuit 730.

[0068] In some embodiments, the LoS state of the UE (e.g., the UE 302 in Fig. 3) is identified, when a median or average of the plurality of estimation errors determined at the processing circuit 730, for a given candidate point i, meets a predetermined condition as explained above with respect to the LoS classification algorithm 400 in Fig. 4. In some embodiments, the processing circuit 730 is configured to determine the plurality of estimation errors for each of the set of the candidate points i, until the LoS state of the UE (i.e., the UE 302 in Fig. 3) is identified based on the determined plurality of estimation errors for a candidate point i of the set or until all the candidate points of the set are exhausted. Upon determining if the UE is in an LoS state or a non-LoS state, the processing circuit 730 is further configured to provide a feedback message (e.g., the LoS indicator message 306b in Fig. 2) to the UE (e.g., the UE 304 in Fig. 3), via the transmitter circuit 720. In some embodiments, the feedback message comprises information on the LoS/n-LoS state of the UE (e.g., the UE 304 in Fig. 3).

[0069] In some embodiments, in order to implement the LoS ray localization algorithm 500 (to determine the set of candidate points i), the processing circuit 730 is configured to construct a grid in theta and phi, in a coverage area of a maximum signal- to-noise ratio (SNR) achieving beam direction corresponding to the uplink transmission 306a in Fig. 3). In some embodiments, the grid corresponds to a plurality of LoS ray locations (theta-j, phi-j), for j = 1 to x, that approximate the location of LoS ray (i.e., the LoS ray of the uplink transmission 306a). The processing circuit 730 is further configured to determine a beam pair direction (k, k") that satisfies a predetermined condition, as explained above with respect to the LoS ray localization algorithm 500 in Fig. 5a. For each LoS ray location j and the beam pair direction (k, k"), the processing circuit 730 is configured to determine an error value corresponding to a difference between the ratio of the calculated array gain of the LoS ray (i.e., the LoS ray of the uplink transmission 306a) and the ratio of the measured SNR of the beam pair direction (k, k"). In some embodiments, an LoS ray location j is identified as a candidate point i, at the processing circuit 730, when the error value satisfies a predetermined condition as explained above with respect to the LoS ray localization algorithm 500 in Fig. 5a.

[0070] Fig. 8 illustrates a flow chart of a method 800 for a user equipment (UE) in a wireless communication network, according to one embodiment of the disclosure. The method 800 is explained herein with reference to the apparatus 600 in Fig. 6. In some embodiments, the apparatus 600 could be included within the UE 204 in Fig. 2. At 802, a downlink transmission from a serving eNodeB is received at the processing circuit 630, via the receive circuit 610, in a plurality of beam directions. Upon receiving the downlink transmission, in some embodiments, the processing circuit 630 is configured to determine an LoS state of the UE based on the downlink transmission by

implementing the LoS classification algorithm 400 in Fig. 4. For example, at 804, a set of candidate points that approximate the location of the LoS ray of the downlink transmission is determined at the processing circuit 630, based on the downlink transmission, in accordance with the LoS ray localization algorithm 500 explained above in Fig. 5a. At 806, a plurality of beam pair directions is determined at the processing circuit 630, based on the downlink transmission, in accordance with the LoS

classification algorithm 400 explained above in Fig. 4. In some embodiments, the LoS ray localization algorithm 500 and the LoS classification algorithm 400 is implemented by the processing circuit 630 based on instructions stored in the memory circuit 640.

[0071] At 808, a plurality of estimation errors is determined at the processing circuit 630 for a candidate point of the set of candidate points and the plurality of beam pair directions. In some embodiments, the plurality of estimation errors is successively determined at the processing circuit 630, for each candidate point of the set of candidate points, until an LoS state of a UE is determined based on the plurality of estimation errors for a candidate point of the set, or until all the candidate points of the set are exhausted. At 810, an LoS/n-LoS state of the UE is identified at the processing circuit, when a median or average of a plurality of estimation errors for a candidate point of the set satisfies a predetermined condition, as explained above in the LoS

classification algorithm 400 in Fig. 4. At 812, a feedback message comprising information on the LoS state of the UE is generated at the processing circuit 630 and provided to the serving eNodeB, via the transmitter circuit 620. [0072] Fig. 9 illustrates a flow chart of a method 900 for an eNodeB in a wireless communication network, according to one embodiment of the disclosure. The method 900 is explained herein with reference to the apparatus 700 in Fig. 7. In some embodiments, the apparatus 700 could be included within the eNodeB 302 in Fig. 3. At 902, an uplink transmission from a UE is received at the processing circuit 730, via the receive circuit 710, in a plurality of beam directions. Upon receiving the uplink transmission, in some embodiments, the processing circuit 730 is configured to determine an LoS state of the UE based on the uplink transmission by implementing the LoS classification algorithm 400 in Fig. 4. For example, at 904, a set of candidate points that approximate the location of the LoS ray of the uplink transmission is determined at the processing circuit 730, based on the uplink transmission, in accordance with the LoS ray localization algorithm 500 explained above in Fig. 5a. At 906, a plurality of beam pair directions is determined at the processing circuit 730, based on the uplink transmission, in accordance with the LoS classification algorithm 400 explained above in Fig. 4. In some embodiments, the LoS ray localization algorithm 500 and the LoS classification algorithm 400 is implemented by the processing circuit 730 based on instructions stored in the memory circuit 740.

[0073] At 908, a plurality of estimation errors is determined at the processing circuit 730, for a candidate point of the set of candidate points and the plurality of beam pair directions. In some embodiments, the plurality of estimation errors is successively determined at the processing circuit 730, for each candidate point of the set of candidate points, until an LoS state of a UE is determined based on the plurality of estimation errors for a candidate point of the set, or until all the candidate points of the set are exhausted. At 910, an LoS/n-LoS state of the UE is identified at the processing circuit 730, when a median or average of a plurality of estimation errors for a candidate point of the set satisfies a predetermined condition, as explained above in the LoS classification algorithm 400 in Fig. 4. At 912, a feedback message comprising information on the LoS state of the UE is generated at the processing circuit 730 and provided to the UE, via the transmitter circuit 720.

[0074] While the methods are illustrated and described above as a series of acts or events, it will be appreciated that the illustrated ordering of such acts or events are not to be interpreted in a limiting sense. For example, some acts may occur in different orders and/or concurrently with other acts or events apart from those illustrated and/or described herein. In addition, not all illustrated acts may be required to implement one or more aspects or embodiments of the disclosure herein. Also, one or more of the acts depicted herein may be carried out in one or more separate acts and/or phases.

[0075] While the apparatus has been illustrated and described with respect to one or more implementations, alterations and/or modifications may be made to the illustrated examples without departing from the spirit and scope of the appended claims. In particular regard to the various functions performed by the above described

components or structures (assemblies, devices, circuits, systems, etc.), the terms (including a reference to a "means") used to describe such components are intended to correspond, unless otherwise indicated, to any component or structure which performs the specified function of the described component (e.g., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary implementations of the invention.

[0076] In particular regard to the various functions performed by the above described components (assemblies, devices, circuits, systems, etc.), the terms (including a reference to a "means") used to describe such components are intended to correspond, unless otherwise indicated, to any component or structure which performs the specified function of the described component (e.g., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary implementations of the disclosure. In addition, while a particular feature may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular application.

[0077] Embodiments described herein may be implemented into a system using any suitably configured hardware and/or software. Fig. 10 illustrates, for one embodiment, example components of a User Equipment (UE) device 1000. In some embodiments, the UE device 1000 may include application circuitry 1002, baseband circuitry 1 004, Radio Frequency (RF) circuitry 1006, front-end module (FEM) circuitry 1008 and one or more antennas 1010, coupled together at least as shown. In some embodiments, the UE 1000 can be a part of the UE 204 in Fig. 2 or the UE 304 in Fig. 3. In some embodiments, the components/circuitry in Fig. 10 can also be part of an eNodeB, for example, the eNodeB 202 in Fig. 2 or the eNodeB 302 in Fig. 3.

[0078] The application circuitry 1002 may include one or more application

processors. For example, the application circuitry 1002 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The processor(s) may include any combination of general-purpose processors and dedicated processors (e.g., graphics processors, application processors, etc.). The processors may be coupled with and/or may include memory/storage and may be configured to execute instructions stored in the memory/storage to enable various applications

and/or operating systems to run on the system.

[0079] The baseband circuitry 1004 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The baseband circuitry 1004 may include one or more baseband processors and/or control logic to process baseband signals received from a receive signal path of the RF circuitry 1006 and to generate baseband signals for a transmit signal path of the RF circuitry 1006. Baseband processing circuity 1004 may interface with the application circuitry 1002 for generation and processing of the baseband signals and for controlling operations of the RF circuitry 1006. For example, in some embodiments, the baseband circuitry 1004 may include a second generation (2G) baseband processor 1004a, third generation (3G) baseband processor 1004b, fourth generation (4G) baseband processor 1004c, and/or other baseband processor(s) 1004d for other existing generations, generations in

development or to be developed in the future (e.g., fifth generation (5G), 6G, etc.). The baseband circuitry 1004 (e.g., one or more of baseband processors 1004a-d) may handle various radio control functions that enable communication with one or more radio networks via the RF circuitry 1006. The radio control functions may include, but are not limited to, signal modulation/demodulation, encoding/decoding, radio

frequency shifting, etc. In some embodiments, modulation/demodulation circuitry of the baseband circuitry 1004 may include Fast-Fourier Transform (FFT), precoding, and/or constellation mapping/demapping functionality. In some embodiments,

encoding/decoding circuitry of the baseband circuitry 1004 may include convolution, tail- biting convolution, turbo, Viterbi, and/or Low Density Parity Check (LDPC) encoder/decoder functionality. Embodiments of modulation/demodulation and encoder/decoder functionality are not limited to these examples and may include other suitable functionality in other embodiments.

[0080] In some embodiments, the baseband circuitry 1004 may include elements of a protocol stack such as, for example, elements of an evolved universal terrestrial radio access network (EUTRAN) protocol including, for example, physical (PHY), media access control (MAC), radio link control (RLC), packet data convergence protocol (PDCP), and/or radio resource control (RRC) elements. A central processing unit (CPU) 1004e of the baseband circuitry 1004 may be configured to run elements of the protocol stack for signaling of the PHY, MAC, RLC, PDCP and/or RRC layers. In some embodiments, the baseband circuitry may include one or more audio digital signal processor(s) (DSP) 1004f. The audio DSP(s) 1004f may be include elements for compression/decompression and echo cancellation and may include other suitable processing elements in other embodiments. Components of the baseband circuitry may be suitably combined in a single chip, a single chipset, or disposed on a same circuit board in some embodiments. In some embodiments, some or all of the constituent components of the baseband circuitry 1004 and the application circuitry 1002 may be implemented together such as, for example, on a system on a chip (SOC).

[0081] In some embodiments, the baseband circuitry 1004 may provide for communication compatible with one or more radio technologies. For example, in some embodiments, the baseband circuitry 1004 may support communication with an evolved universal terrestrial radio access network (EUTRAN) and/or other wireless metropolitan area networks (WMAN), a wireless local area network (WLAN), a wireless personal area network (WPAN). Embodiments in which the baseband circuitry 1004 is configured to support radio communications of more than one wireless protocol may be referred to as multi-mode baseband circuitry.

[0082] RF circuitry 1006 may enable communication with wireless networks using modulated electromagnetic radiation through a non-solid medium. In various embodiments, the RF circuitry 1006 may include switches, filters, amplifiers, etc. to facilitate the communication with the wireless network. RF circuitry 1006 may include a receive signal path which may include circuitry to down-convert RF signals received from the FEM circuitry 1008 and provide baseband signals to the baseband circuitry 1004. RF circuitry 1006 may also include a transmit signal path which may include circuitry to up-convert baseband signals provided by the baseband circuitry 1004 and provide RF output signals to the FEM circuitry 1008 for transmission.

[0083] In some embodiments, the RF circuitry 1006 may include a receive signal path and a transmit signal path. The receive signal path of the RF circuitry 1006 may include mixer circuitry 1006a, amplifier circuitry 1006b and filter circuitry 1006c. The transmit signal path of the RF circuitry 1006 may include filter circuitry 1 006c and mixer circuitry 1006a. RF circuitry 1006 may also include synthesizer circuitry 1006d for synthesizing a frequency for use by the mixer circuitry 1006a of the receive signal path and the transmit signal path. In some embodiments, the mixer circuitry 1006a of the receive signal path may be configured to down-convert RF signals received from the FEM circuitry 1008 based on the synthesized frequency provided by synthesizer circuitry 1006d. The amplifier circuitry 1006b may be configured to amplify the down- converted signals and the filter circuitry 1006c may be a low-pass filter (LPF) or bandpass filter (BPF) configured to remove unwanted signals from the down-converted signals to generate output baseband signals. Output baseband signals may be provided to the baseband circuitry 1004 for further processing. In some embodiments, the output baseband signals may be zero-frequency baseband signals, although this is not a requirement. In some embodiments, mixer circuitry 1006a of the receive signal path may comprise passive mixers, although the scope of the embodiments is not limited in this respect.

[0084] In some embodiments, the mixer circuitry 1006a of the transmit signal path may be configured to up-convert input baseband signals based on the synthesized frequency provided by the synthesizer circuitry 1006d to generate RF output signals for the FEM circuitry 1008. The baseband signals may be provided by the baseband circuitry 1004 and may be filtered by filter circuitry 1006c. The filter circuitry 1006c may include a low-pass filter (LPF), although the scope of the embodiments is not limited in this respect.

[0085] In some embodiments, the mixer circuitry 1006a of the receive signal path and the mixer circuitry 1006a of the transmit signal path may include two or more mixers and may be arranged for quadrature downconversion and/or upconversion respectively. In some embodiments, the mixer circuitry 1006a of the receive signal path and the mixer circuitry 1 006a of the transmit signal path may include two or more mixers and may be arranged for image rejection (e.g., Hartley image rejection). In some

embodiments, the mixer circuitry 1006a of the receive signal path and the mixer circuitry 1006a may be arranged for direct downconversion and/or direct upconversion, respectively. In some embodiments, the mixer circuitry 1006a of the receive signal path and the mixer circuitry 1006a of the transmit signal path may be configured for superheterodyne operation.

[0086] In some embodiments, the output baseband signals and the input baseband signals may be analog baseband signals, although the scope of the embodiments is not limited in this respect. In some alternate embodiments, the output baseband signals and the input baseband signals may be digital baseband signals. In these alternate embodiments, the RF circuitry 1006 may include analog-to-digital converter (ADC) and digital-to-analog converter (DAC) circuitry and the baseband circuitry 1004 may include a digital baseband interface to communicate with the RF circuitry 1006.

[0087] In some dual-mode embodiments, a separate radio IC circuitry may be provided for processing signals for each spectrum, although the scope of the

embodiments is not limited in this respect.

[0088] In some embodiments, the synthesizer circuitry 1006d may be a fractional-N synthesizer or a fractional N/N+1 synthesizer, although the scope of the embodiments is not limited in this respect as other types of frequency synthesizers may be suitable. For example, synthesizer circuitry 1006d may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer comprising a phase-locked loop with a frequency divider.

[0089] The synthesizer circuitry 1006d may be configured to synthesize an output frequency for use by the mixer circuitry 1006a of the RF circuitry 1006 based on a frequency input and a divider control input. In some embodiments, the synthesizer circuitry 1006d may be a fractional N/N+1 synthesizer.

[0090] In some embodiments, frequency input may be provided by a voltage controlled oscillator (VCO), although that is not a requirement. Divider control input may be provided by either the baseband circuitry 1004 or the applications processor 1002 depending on the desired output frequency. In some embodiments, a divider control input (e.g., N) may be determined from a look-up table based on a channel indicated by the applications processor 1 002.

[0091] Synthesizer circuitry 1006d of the RF circuitry 1006 may include a divider, a delay-locked loop (DLL), a multiplexer and a phase accumulator. In some embodiments, the divider may be a dual modulus divider (DMD) and the phase accumulator may be a digital phase accumulator (DPA). In some embodiments, the DMD may be configured to divide the input signal by either N or N+1 (e.g., based on a carry out) to provide a fractional division ratio. In some example embodiments, the DLL may include a set of cascaded, tunable, delay elements, a phase detector, a charge pump and a D-type flip- flop. In these embodiments, the delay elements may be configured to break a VCO period up into Nd equal packets of phase, where Nd is the number of delay elements in the delay line. In this way, the DLL provides negative feedback to help ensure that the total delay through the delay line is one VCO cycle.

[0092] In some embodiments, synthesizer circuitry 1006d may be configured to generate a carrier frequency as the output frequency, while in other embodiments, the output frequency may be a multiple of the carrier frequency (e.g., twice the carrier frequency, four times the carrier frequency) and used in conjunction with quadrature generator and divider circuitry to generate multiple signals at the carrier frequency with multiple different phases with respect to each other. In some embodiments, the output frequency may be a LO frequency (fLO). In some embodiments, the RF circuitry 1006 may include an IQ/polar converter.

[0093] FEM circuitry 1008 may include a receive signal path which may include circuitry configured to operate on RF signals received from one or more antennas 1010, amplify the received signals and provide the amplified versions of the received signals to the RF circuitry 1006 for further processing. FEM circuitry 1008 may also include a transmit signal path which may include circuitry configured to amplify signals for transmission provided by the RF circuitry 1006 for transmission by one or more of the one or more antennas 1010. [0094] In some embodiments, the FEM circuitry 1008 may include a TX/RX switch to switch between transmit mode and receive mode operation. The FEM circuitry may include a receive signal path and a transmit signal path. The receive signal path of the FEM circuitry may include a low-noise amplifier (LNA) to amplify received RF signals and provide the amplified received RF signals as an output (e.g., to the RF circuitry 1006). The transmit signal path of the FEM circuitry 1 008 may include a power amplifier (PA) to amplify input RF signals (e.g., provided by RF circuitry 1006), and one or more filters to generate RF signals for subsequent transmission (e.g., by one or more of the one or more antennas 1010.

[0095] In some embodiments, the UE device 1000 may include additional elements such as, for example, memory/storage, display, camera, sensor, and/or input/output (I/O) interface.

[0096] While the invention has been illustrated, and described with respect to one or more implementations, alterations and/or modifications may be made to the illustrated examples without departing from the spirit and scope of the appended claims. In particular regard to the various functions performed by the above described

components or structures (assemblies, devices, circuits, systems, etc.), the terms (including a reference to a "means") used to describe such components are intended to correspond, unless otherwise indicated, to any component or structure which performs the specified function of the described component (e.g., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary implementations of the invention.

[0097] The foregoing description of one or more implementations provides illustration and description, but is not intended to be exhaustive or to limit the scope of the example embodiments to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of various

implementations of the example embodiments.

[0098] In the present disclosure like reference numerals are used to refer to like elements throughout, and wherein the illustrated structures and devices are not necessarily drawn to scale. As utilized herein, terms "module", "component," "system," "circuit," "circuitry," "element," "slice," and the like are intended to refer to a computer- related entity, hardware, software (e.g., in execution), and/or firmware. For example, circuitry or a similar term can be a processor, a process running on a processor, a controller, an object, an executable program, a storage device, and/or a computer with a processing device. By way of illustration, an application running on a server and the server can also be circuitry. One or more circuitries can reside within a process, and circuitry can be localized on one computer and/or distributed between two or more computers. A set of elements or a set of other circuitry can be described herein, in which the term "set" can be interpreted as "one or more."

[0099] As another example, circuitry or similar term can be an apparatus with specific functionality provided by mechanical parts operated by electric or electronic circuitry, in which the electric or electronic circuitry can be operated by a software application or a firmware application executed by one or more processors. The one or more processors can be internal or external to the apparatus and can execute at least a part of the software or firmware application. As yet another example, circuitry can be an apparatus that provides specific functionality through electronic components without mechanical parts; the electronic components can include one or more processors therein to execute software and/or firmware that confer(s), at least in part, the

functionality of the electronic components.

[00100] It will be understood that when an element is referred to as being "electrically connected" or "electrically coupled" to another element, it can be physically connected or coupled to the other element such that current and/or electromagnetic radiation can flow along a conductive path formed by the elements. Intervening conductive, inductive, or capacitive elements may be present between the element and the other element when the elements are described as being electrically coupled or connected to one another. Further, when electrically coupled or connected to one another, one element may be capable of inducing a voltage or current flow or propagation of an electromagnetic wave in the other element without physical contact or intervening components. Further, when a voltage, current, or signal is referred to as being "applied" to an element, the voltage, current, or signal may be conducted to the element by way of a physical connection or by way of capacitive, electro-magnetic, or inductive coupling that does not involve a physical connection. [00101 ] Use of the word exemplary is intended to present concepts in a concrete fashion. The terminology used herein is for the purpose of describing particular examples only and is not intended to be limiting of examples. As used herein, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises," "comprising," "includes" and/or "including," when used herein, specify the presence of stated features, integers, steps, operations, elements and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof.

[00102] Examples can include subject matter such as a method, means for performing acts or blocks of the method, at least one machine-readable medium including instructions that, when performed by a machine cause the machine to perform acts of the method or of an apparatus or system for concurrent communication using multiple communication technologies according to embodiments and examples described herein.

[00103] Example 1 is an apparatus for use in a user equipment (UE) of a wireless communication network that facilitates determining a line of sight (LoS) state of the UE with respect to a serving eNodeB, comprising one or more processors; and a memory including instructions comprising operations, for execution via the one or more processors to, receive a downlink transmission from the serving eNodeB in a plurality of beam directions with respect to the UE; determine a plurality of estimation errors based on the received downlink transmission; and identify the LoS state of the UE based on the determined plurality of estimation errors.

[00104] Example 2 is an apparatus, including the subject matter of example 1 , wherein the plurality of estimation errors associated with the downlink transmission is determined for a set of respective beam pair directions, each beam pair direction of the set comprising a first direction and a second, different direction of the plurality of beam directions and wherein the estimation error for a respective beam pair direction is determined based on a measured signal-to-noise ratio (SNR) of the downlink transmission at the UE in the respective first direction and the respective second direction, and an array gain of the UE in the respective first direction and the respective second direction.

[00105] Example 3 is an apparatus, including the subject matter of examples 1 -2, including or omitting elements, wherein the first direction and the second direction of a respective beam pair direction are chosen such that a ratio of a measured signal-to- noise ratio (SNR) of the downlink transmission in the first direction and in the second direction is less than a predetermined value, and wherein the first direction is a maximum SNR achieving direction of the downlink transmission or a direction in which a measured SNR of the downlink transmission is greater than a predetermined SNR threshold.

[00106] Example 4 is an apparatus, including the subject matter of examples 1 -3, including or omitting elements, wherein the LoS state of the UE is identified when an average of the plurality of estimation errors or a median of the plurality of estimation errors is less than a predetermined threshold; and the plurality of estimation errors comprises at least a predetermined number of estimation errors.

[00107] Example 5 is an apparatus, including the subject matter of examples 1 -4, including or omitting elements, wherein the one or more processors is further configured to determine a set of candidate points that approximates a location of an LoS ray of the downlink transmission, prior to determining the plurality of estimation errors, wherein each of the candidate points of the set comprises a zenith angle of arrival and an azimuth angle of arrival associated with the LoS ray of the downlink transmission and wherein determining the plurality of estimation errors comprises determining the plurality of estimation errors for one or more candidate points of the set.

[00108] Example 6 is an apparatus, including the subject matter of examples 1 -5, including or omitting elements, wherein determining the plurality of estimation errors for one or more candidate points of the set comprises successively determining the plurality of estimation errors for each of the candidate points of the set, until the LoS state of the UE is identified based on the determined plurality of estimation errors for a candidate point of the set or until all the candidate points of the set are exhausted. [00109] Example 7 is an apparatus, including the subject matter of examples 1 -6, including or omitting elements, wherein determining the set of candidate points comprises determining a grid comprising a plurality of LoS locations in a coverage area of a maximum SNR achieving beam direction of the downlink transmission, wherein each of the plurality of LoS locations of the grid is identified by a respective zenith angle of arrival and a respective azimuth angle of arrival.

[00110] Example 8 is an apparatus, including the subject matter of examples 1 -7, including or omitting elements, wherein determining the set of candidate points further comprises determining a reference beam direction different from the maximum SNR achieving beam direction such that, a measured SNR ratio comprising a ratio of a measured SNR of the downlink transmission in the maximum SNR achieving beam direction and the reference beam direction is lesser than or equal to a LoS threshold, and the coverage area of the maximum SNR achieving beam direction and a coverage area of the reference beam direction does not overlap.

[00111 ] Example 9 is an apparatus, including the subject matter of examples 1 -8, including or omitting elements, wherein determining the set of candidate points further comprises determining a calculated array gain ratio comprising a ratio of a calculated array gain of the downlink transmission in the maximum SNR achieving beam direction and the reference beam direction for each of the plurality of LoS locations.

[00112] Example 10 is an apparatus, including the subject matter of examples 1 -9, including or omitting elements, wherein determining the set of candidate points further comprises determining an error value comprising a difference between the calculated array gain ratio and the measured SNR ratio for each of the plurality of LoS locations, and identifying an LoS location as a candidate point based on a comparison of the error value with a predetermined candidate threshold.

[00113] Example 1 1 is an apparatus, including the subject matter of examples 1 -10, including or omitting elements, wherein the one or more processors is further configured to provide a feedback message to the serving eNodeB, wherein the feedback message comprises an indicator that indicates whether the UE has an LoS state with the serving eNodeB or not. [00114] Example 12 is an apparatus for use in a user equipment (UE) of a wireless communication network that facilitates determining a line of sight (LoS) state of the UE with respect to a serving eNodeB, comprising one or more processors; and a memory including instructions comprising operations, for execution via the one or more processors to, receive a downlink transmission from the serving eNodeB in a plurality of beam directions with respect to the UE; determine a plurality of estimation errors associated with the downlink transmission for a set of respective beam pair directions, each beam pair direction of the set comprising a first direction and a second, different, direction of the plurality of beam directions, wherein the estimation error for a respective beam pair direction is determined based on a measured signal-to-noise ratio (SNR) of the downlink transmission at the UE in the respective first direction and the respective second direction, and an array gain of the UE in the respective first direction and the respective second direction; and identify the LoS state of the UE based on a

comparison of an average of the plurality of estimation errors to a predetermined threshold or based on a comparison of a median of the plurality of estimation errors to a predetermined threshold.

[00115] Example 13 is an apparatus, including the subject matter of example 12, wherein the LoS state of the UE is identified when an average of the plurality of estimation errors or a median of the plurality of estimation errors is less than a predetermined threshold; and the plurality of estimation errors comprises at least a predetermined number of estimation errors.

[00116] Example 14 is an apparatus, including the subject matter of examples 1 2-13, including or omitting elements, wherein the one or more processors is further configured to determine a set of candidate points that approximates a location of an LoS ray of the downlink transmission, prior to determining the plurality of estimation errors, wherein each of the candidate points of the set comprises a zenith angle of arrival and an azimuth angle of arrival associated with the LoS ray of the downlink transmission and wherein determining the plurality of estimation errors comprises determining the plurality of estimation errors for one or more candidate points of the set.

[00117] Example 15 is an apparatus, including the subject matter of examples 1 2-14, including or omitting elements, wherein determining the plurality of estimation errors for one or more candidate points of the set comprises successively determining the plurality of estimation errors for each of the candidate points of the set, until the LoS state of the UE is identified based on the determined plurality of estimation errors for a candidate point of the set or until all the candidate points of the set are exhausted.

[00118] Example 16 is an apparatus, including the subject matter of examples 1 2-15, including or omitting elements, wherein the one or more processors is further configured to provide a feedback message to the eNodeB, wherein the feedback message comprises an indicator that indicates whether the UE has an LoS state with the serving eNodeB or not.

[00119] Example 17 is an apparatus for use in an eNodeB of a wireless

communication network that facilitates determining a line of sight (LoS) state of a UE with respect to the eNodeB, comprising one or more processors; and a memory including instructions comprising operations, for execution via the one or more processors to, receive an uplink transmission from the UE in a plurality of beam directions with respect to the eNodeB; determine a plurality of estimation errors based on the received uplink transmission; and identify the LoS state of the UE based on the determined plurality of estimation errors.

[00120] Example 18 is an apparatus, including the subject matter of example 17, wherein the plurality of estimation errors associated with the uplink transmission is determined for a set of respective beam pair directions, each beam pair direction of the set comprising a first direction and a second, different direction of the plurality of beam directions and wherein the estimation error for a respective beam pair direction is determined based on a measured signal-to-noise ratio (SNR) of the uplink transmission at the eNodeB in the respective first direction and the respective second direction, and an array gain of the eNodeB in the respective first direction and the respective second direction.

[00121 ] Example 19 is an apparatus, including the subject matter of examples 1 7-18, including or omitting elements, wherein the first direction and the second direction of a respective beam pair direction are chosen such that a ratio of a measured signal-to- noise ratio (SNR) of the uplink transmission in the first direction and in the second direction is less than a predetermined value, and wherein the first direction is a maximum SNR achieving direction of the uplink transmission or a direction in which a measured SNR of the uplink transmission is greater than a predetermined SNR threshold.

[00122] Example 20 is an apparatus, including the subject matter of examples 1 7-19, including or omitting elements, wherein the LoS state of the UE is identified when an average of the plurality of estimation errors or a median of the plurality of estimation errors is less than a predetermined threshold; and the plurality of estimation errors comprises at least a predetermined number of estimation errors.

[00123] Example 21 is an apparatus, including the subject matter of examples 1 7-20, including or omitting elements, wherein the one or more processors is further configured to determine a set of candidate points that approximates a location of an LoS ray of the uplink transmission, prior to determining the plurality of estimation errors, wherein each of the candidate points of the set comprises a zenith angle of arrival and an azimuth angle of arrival associated with the LoS ray of the uplink transmission and wherein determining the plurality of estimation errors comprises determining the plurality of estimation errors for one or more candidate points of the set.

[00124] Example 22 is an apparatus, including the subject matter of examples 1 7-21 , including or omitting elements, wherein determining the plurality of estimation errors for one or more candidate points of the set comprises successively determining the plurality of estimation errors for each of the candidate points of the set, until the LoS state of the UE is identified based on the determined plurality of estimation errors for a candidate point of the set or until all the candidate points of the set are exhausted.

[00125] Example 23 is an apparatus, including the subject matter of examples 1 7-22, including or omitting elements, wherein determining the set of candidate points comprises determining a grid comprising a plurality of LoS locations in a coverage area of a maximum SNR achieving beam direction of the uplink transmission, wherein each of the plurality of LoS locations of the grid is identified by a respective zenith angle of arrival and a respective azimuth angle of arrival.

[00126] Example 24 is an apparatus, including the subject matter of examples 1 7-23, including or omitting elements, wherein determining the set of candidate points further comprises determining a reference beam direction different from the maximum SNR achieving beam direction such that, a measured SNR ratio comprising a ratio of a measured SNR of the uplink transmission in the maximum SNR achieving beam direction and the reference beam direction is lesser than or equal to a LoS threshold, and the coverage area of the maximum SNR achieving beam direction and a coverage area of the reference beam direction does not overlap.

[00127] Example 25 is an apparatus, including the subject matter of examples 1 7-24, including or omitting elements, wherein determining the set of candidate points further comprises determining a calculated array gain ratio comprising a ratio of a calculated array gain of the uplink transmission in the maximum SNR achieving beam direction and the reference beam direction for each of the plurality of LoS locations.

[00128] Example 26 is an apparatus, including the subject matter of examples 1 7-25, including or omitting elements, wherein determining the set of candidate points further comprises determining an error value comprising a difference between the calculated array gain ratio and the measured SNR ratio for each of the plurality of LoS locations, and identifying an LoS location as a candidate point based on a comparison of the error value with a predetermined candidate threshold.

[00129] Example 27 is an apparatus for use in an eNodeB of a wireless

communication network that facilitates determining a line of sight (LoS) state of a UE with respect to the eNodeB, comprising one or more processors; and a memory including instructions comprising operations, for execution via the one or more processors to, receive a uplink transmission from the UE in a plurality of beam directions with respect to the eNodeB; determine a plurality of estimation errors associated with the uplink transmission for a set of respective beam pair directions, each beam pair direction of the set comprising a first direction and a second, different, direction of the plurality of beam directions, wherein the estimation error for a respective beam pair direction is determined based on a measured signal-to-noise ratio (SNR) of the uplink transmission at the eNodeB in the respective first direction and the respective second direction, and an array gain of the eNodeB in the respective first direction and the respective second direction; and identify a line of sight (LoS) state of the UE based on a comparison of an average or a median of the plurality of estimation errors to a predetermined threshold.

[00130] Example 28 is an apparatus, including the subject matter of examples 27, wherein the LoS state of the UE is identified when an average of the plurality of estimation errors or a median of the plurality of estimation errors is less than a predetermined threshold; and the plurality of estimation errors comprises at least a predetermined number of estimation errors.

[00131 ] Example 29 is an apparatus, including the subject matter of examples 27-28, including or omitting elements, wherein the one or more processors is further configured to determine a set of candidate points that approximates a location of an LoS ray of the uplink transmission, prior to determining the plurality of estimation errors, wherein each of the candidate points of the set comprises a zenith angle of arrival and an azimuth angle of arrival associated with the LoS ray of the uplink transmission and wherein determining the plurality of estimation errors comprises determining the plurality of estimation errors for one or more candidate points of the set.

[00132] Example 30 is an apparatus, including the subject matter of examples 27-29, including or omitting elements, wherein determining the plurality of estimation errors for one or more candidate points of the set comprises successively determining the plurality of estimation errors for each of the candidate points of the set, until the LoS state of the UE is identified based on the determined plurality of estimation errors for a candidate point of the set or until all the candidate points of the set are exhausted.

[00133] Example 31 is a method for use in a user equipment (UE) of a wireless communication network to determine a line of sight (LoS) state of the UE with respect to a serving eNodeB, comprising receiving, at one or more processors, a downlink transmission from the serving eNodeB in a plurality of beam directions with respect to the UE; determining, at the one or more processors, a plurality of estimation errors based on the received downlink transmission; and identifying, at the one or more processors, the LoS state of the UE based on the determined plurality of estimation errors. [00134] Example 32 is a method, including the subject matter of example 31 , wherein the plurality of estimation errors associated with the downlink transmission is

determined for a set of respective beam pair directions, each beam pair direction of the set comprising a first direction and a second, different direction of the plurality of beam directions and wherein the estimation error for a respective beam pair direction is determined based on a measured signal-to-noise ratio (SNR) of the downlink transmission at the UE in the respective first direction and the respective second direction, and an array gain of the UE in the respective first direction and the respective second direction.

[00135] Example 33 is a method, including the subject matter of examples 31 -32, including or omitting elements, wherein the first direction and the second direction of a respective beam pair direction are chosen such that a ratio of a measured signal-to- noise ratio (SNR) of the downlink transmission in the first direction and in the second direction is less than a predetermined value, and wherein the first direction is a maximum SNR achieving direction of the downlink transmission or a direction in which a measured SNR of the downlink transmission is greater than a predetermined SNR threshold.

[00136] Example 34 is a method, including the subject matter of examples 31 -33, including or omitting elements, wherein the LoS state of the UE is identified when an average of the plurality of estimation errors or a median of the plurality of estimation errors is less than a predetermined threshold; and the plurality of estimation errors comprises at least a predetermined number of estimation errors.

[00137] Example 35 is a method, including the subject matter of examples 31 -34, including or omitting elements, further comprising, determining at the one or more processors, a set of candidate points that approximates a location of an LoS ray of the downlink transmission, prior to determining the plurality of estimation errors, wherein each of the candidate points of the set comprises a zenith angle of arrival and an azimuth angle of arrival associated with the LoS ray of the downlink transmission and wherein determining the plurality of estimation errors comprises determining the plurality of estimation errors for one or more candidate points of the set. [00138] Example 36 is a method, including the subject matter of examples 31 -35, including or omitting elements, wherein determining the plurality of estimation errors for one or more candidate points of the set comprises successively determining the plurality of estimation errors for each of the candidate points of the set, until the LoS state of the UE is identified based on the determined plurality of estimation errors for a candidate point of the set or until all the candidate points of the set are exhausted.

[00139] Example 37 is a method, including the subject matter of examples 31 -36, including or omitting elements, wherein determining the set of candidate points comprises determining a grid comprising a plurality of LoS locations in a coverage area of a maximum SNR achieving beam direction of the downlink transmission, wherein each of the plurality of LoS locations of the grid is identified by a respective zenith angle of arrival and a respective azimuth angle of arrival.

[00140] Example 38 is a method, including the subject matter of examples 31 -37, including or omitting elements, wherein determining the set of candidate points further comprises determining a reference beam direction different from the maximum SNR achieving beam direction such that a measured SNR ratio comprising a ratio of a measured SNR of the downlink transmission in the maximum SNR achieving beam direction and the reference beam direction is lesser than or equal to a LoS threshold, and the coverage area of the maximum SNR achieving beam direction and a coverage area of the reference beam direction does not overlap.

[00141 ] Example 39 is a method, including the subject matter of examples 31 -38, including or omitting elements, wherein determining the set of candidate points further comprises determining a calculated array gain ratio comprising a ratio of a calculated array gain of the downlink transmission in the maximum SNR achieving beam direction and the reference beam direction for each of the plurality of LoS locations.

[00142] Example 40 is a method, including the subject matter of examples 31 -39, including or omitting elements, wherein determining the set of candidate points further comprises determining an error value comprising a difference between the calculated array gain ratio and the measured SNR ratio for each of the plurality of LoS locations, and identifying an LoS location as a candidate point based on a comparison of the error value with a predetermined candidate threshold. [00143] Example 41 is a method, including the subject matter of examples 31 -40, including or omitting elements, further comprising, providing by the one or more processors, a feedback message to the eNodeB, wherein the feedback message comprises an indicator that indicates whether the UE has an LoS state with the serving eNodeB or not.

[00144] Example 42 is a method for use in a user equipment (UE) of a wireless communication network to determine a line of sight (LoS) state of the UE with respect to a serving eNodeB, comprising receiving, at one or more processors, a downlink transmission from the serving eNodeB in a plurality of beam directions with respect to the UE; determining, by the one or more processors, a plurality of estimation errors associated with the downlink transmission for a set of respective beam pair directions, each beam pair direction of the set comprising a first direction and a second, different, direction of the plurality of beam directions, wherein the estimation error for a respective beam pair direction is determined based on a measured signal-to-noise ratio (SNR) of the downlink transmission at the UE in the respective first direction and the respective second direction, and an array gain of the UE in the respective first direction and the respective second direction; and identify, by the one or more processors, the LoS state of the UE based on a comparison of an average of the plurality of estimation errors to a predetermined threshold or based on a comparison of a median of the plurality of estimation errors to a predetermined threshold.

[00145] Example 43 is a method, including the subject matter of example 42, wherein the LoS state of the UE is identified when an average of the plurality of estimation errors or a median of the plurality of estimation errors is less than a predetermined threshold; and the plurality of estimation errors comprises at least a predetermined number of estimation errors.

[00146] Example 44 is a method, including the subject matter of examples 42-43, including or omitting elements, further comprising, determining by the one or more processors, a set of candidate points that approximates a location of an LoS ray of the downlink transmission, prior to determining the plurality of estimation errors, wherein each of the candidate points of the set comprises a zenith angle of arrival and an azimuth angle of arrival associated with the LoS ray of the downlink transmission and wherein determining the plurality of estimation errors comprises determining the plurality of estimation errors for one or more candidate points of the set.

[00147] Example 45 is a method, including the subject matter of examples 42-44, including or omitting elements, wherein determining the plurality of estimation errors for one or more candidate points of the set comprises successively determining the plurality of estimation errors for each of the candidate points of the set, until the LoS state of the UE is identified based on the determined plurality of estimation errors for a candidate point of the set or until all the candidate points of the set are exhausted.

[00148] Example 46 is a method for use in an eNodeB of a wireless communication network to determine a line of sight (LoS) state of a UE with respect to the eNodeB, comprising receiving, at one or more processors, an uplink transmission from the UE in a plurality of beam directions with respect to the eNodeB; determining, by the one or more processors, a plurality of estimation errors based on the received uplink transmission; and identifying, by the one or more processors, the LoS state of the UE based on the determined plurality of estimation errors.

[00149] Example 47 is a method including the subject matter of examples 46, wherein the plurality of estimation errors associated with the uplink transmission is determined for a set of respective beam pair directions, each beam pair direction of the set comprising a first direction and a second, different direction of the plurality of beam directions and wherein the estimation error for a respective beam pair direction is determined based on a measured signal-to-noise ratio (SNR) of the uplink transmission at the eNodeB in the respective first direction and the respective second direction, and an array gain of the eNodeB in the respective first direction and the respective second direction.

[00150] Example 48 is a method including the subject matter of examples 46-47, including or omitting elements, wherein the first direction and the second direction of a respective beam pair direction are chosen such that a ratio of a measured signal-to- noise ratio (SNR) of the uplink transmission in the first direction and in the second direction is less than a predetermined value, and wherein the first direction is a maximum SNR achieving direction of the uplink transmission or a direction in which a measured SNR of the uplink transmission is greater than a predetermined SNR threshold.

[00151 ] Example 49 is a method including the subject matter of examples 46-48, including or omitting elements, wherein the LoS state of the UE is identified when an average of the plurality of estimation errors or a median of the plurality of estimation errors is less than a predetermined threshold; and the plurality of estimation errors comprises at least a predetermined number of estimation errors.

[00152] Example 50 is a method including the subject matter of examples 46-49, including or omitting elements, further comprising, determining by the one or more processors, a set of candidate points that approximates a location of an LoS ray of the uplink transmission, prior to determining the plurality of estimation errors, wherein each of the candidate points of the set comprises a zenith angle of arrival and an azimuth angle of arrival associated with the LoS ray of the uplink transmission and wherein determining the plurality of estimation errors comprises determining the plurality of estimation errors for one or more candidate points of the set.

[00153] Example 51 is a method including the subject matter of examples 46-50, including or omitting elements, wherein determining the plurality of estimation errors for one or more candidate points of the set comprises successively determining the plurality of estimation errors for each of the candidate points of the set, until the LoS state of the UE is identified based on the determined plurality of estimation errors for a candidate point of the set or until all the candidate points of the set are exhausted.

[00154] Example 52 is a method for use in an eNodeB of a wireless communication network to determine a line of sight (LoS) state of a UE with respect to the eNodeB, comprising receiving, at one or more processors, a uplink transmission from the UE in a plurality of beam directions with respect to the eNodeB; determining, by the one or more processors, a plurality of estimation errors associated with the uplink transmission for a set of respective beam pair directions, each beam pair direction of the set comprising a first direction and a second, different, direction of the plurality of beam directions, wherein the estimation error for a respective beam pair direction is determined based on a measured signal-to-noise ratio (SNR) of the uplink transmission at the eNodeB in the respective first direction and the respective second direction, and an array gain of the eNodeB in the respective first direction and the respective second direction; and identifying, by the one or more processors, a line of sight (LoS) state of the UE based on a comparison of an average or a median of the plurality of estimation errors to a predetermined threshold.

[00155] Example 53 is a method including the subject matter of example 52, wherein the LoS state of the UE is identified when an average of the plurality of estimation errors or a median of the plurality of estimation errors is less than a predetermined threshold; and the plurality of estimation errors comprises at least a predetermined number of estimation errors.

[00156] Example 54 is a method including the subject matter of examples 52-53, including or omitting elements, further comprising, determining, by the one or more processors, a set of candidate points that approximates a location of an LoS ray of the uplink transmission, prior to determining the plurality of estimation errors, wherein each of the candidate points of the set comprises a zenith angle of arrival and an azimuth angle of arrival associated with the LoS ray of the uplink transmission and wherein determining the plurality of estimation errors comprises determining the plurality of estimation errors for one or more candidate points of the set.

[00157] Example 55 is a method including the subject matter of examples 52-54, including or omitting elements, wherein determining the plurality of estimation errors for one or more candidate points of the set comprises successively determining the plurality of estimation errors for each of the candidate points of the set, until the LoS state of the UE is identified based on the determined plurality of estimation errors for a candidate point of the set or until all the candidate points of the set are exhausted.

[00158] Various illustrative logics, logical blocks, modules, and circuits described in connection with aspects disclosed herein can be implemented or performed with a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other

programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform functions described herein. A general-purpose processor can be a microprocessor, but, in the alternative, processor can be any conventional processor, controller, microcontroller, or state machine.

[00159] The above description of illustrated embodiments of the subject disclosure, including what is described in the Abstract, is not intended to be exhaustive or to limit the disclosed embodiments to the precise forms disclosed. While specific embodiments and examples are described herein for illustrative purposes, various modifications are possible that are considered within the scope of such embodiments and examples, as those skilled in the relevant art can recognize.

[00160] In this regard, while the disclosed subject matter has been described in connection with various embodiments and corresponding Figures, where applicable, it is to be understood that other similar embodiments can be used or modifications and additions can be made to the described embodiments for performing the same, similar, alternative, or substitute function of the disclosed subject matter without deviating therefrom. Therefore, the disclosed subject matter should not be limited to any single embodiment described herein, but rather should be construed in breadth and scope in accordance with the appended claims below.