TECHNICAL FIELD

[0001] Embodiments pertain to wireless communications. Some embodiments relate to user equipment (UE)-Evolved Node-B (eNodeB) signaling information.

BACKGROUND

[0002] Wireless mobile devices or user equipments (UEs) may communicate with each other using radio access technologies such as the 3GPP Long-Term Evolution (LTE) standard, 3 GPP LTE Advanced Release 12 (March 2014) (the "LTE-A Standard"), the IEEE 802.16 standard, IEEE Std. 802.16- 2009, published May 29, 2009 ("WiMAX"), as well as any other wireless protocols that are designated as 3G, 4G, 5G, and beyond. Technologies such as device-to-device (D2D), sensor networks, or Internet of Things (IoT) (which describes interconnecting uniquely identifiable embedded computing devices within the internet infrastructure) can utilize UEs comprising limited power supplies. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] FIG. 1 illustrates an architecture of components of a cellular network system, in accordance with some embodiments of the disclosure.

[0004] FIG. 2 illustrates an architecture of components of a cellular network system, in accordance with some embodiments of the disclosure.

[0005] FIG. 3 a flow diagram of a method to manage mobility in a low power mode in accordance with some embodiments of the disclosure.

[0006] FIG. 4 a flow diagram of a method to manage mobility in a low power mode in accordance with some embodiments of the disclosure.

[0007] FIG. 5 illustrates a block diagram of components of a User Equipment (UE) device according to embodiments of the disclosure. [0008] FIG. 6 illustrates a block diagram of a machine in the example form of a computer system in accordance with some embodiments of the disclosure.

DETAILED DESCRIPTION

[0009] The following description and the drawings sufficiently illustrate specific embodiments to enable those skilled in the art to practice them. Other embodiments can incorporate structural, logical, electrical, process, and other changes. Portions and features of some embodiments can be included in, or substituted for, those of other embodiments. Embodiments set forth in the claims encompass all available equivalents of those claims.

[0010] In some embodiments, mobile devices or other devices described herein can be part of a portable wireless communication device, such as a personal digital assistant (PDA), a laptop or portable computer with wireless communication capability, a web tablet, a wireless telephone, a smartphone, a wireless headset, a pager, a wearable mobile computing device (e.g., a mobile computing device included in a wearable housing), an instant messaging device, a digital camera, an access point, a television, a medical device (e.g., a heart rate monitor, a blood pressure monitor, etc.), or other device that can receive and/or transmit information wirelessly. In some embodiments, the mobile device or other device can be a user equipment (UE) or an Evolved Node-B (eNodeB) configured to operate in accordance with 3GPP standards (e.g., the 3GPP Long Term Evolution ("LTE") Advanced Release 12 (March 2014) (the "LTE-A Standard")). In some embodiments, the mobile device or other device can be configured to operate according to other protocols or standards, including IEEE 802.11 or other IEEE and 3GPP standards. In some embodiments, the mobile device or other device can include one or more of a keyboard, a display, a non-volatile memory port, multiple antennas, a graphics processor, an application processor, speakers, and other mobile device elements. The display can be a liquid crystal display (LCD) screen including a touch screen.

[0011] FIG. 1 illustrates an architecture of components of a cellular network system 100, in accordance with some embodiments of the disclosure. In this example, the system 100 may include an Evolved Packet System (EPS) on an LTE network, and thus includes an Evolved Universal Terrestrial Access Network (E- UTRAN) core network 104 having a mobility management entity (MME) 106 to communicate with the evolved node Bs (eNodeBs) 110(1-12). In this illustration, only a portion of the components of the E-UTRAN core network 104 and the eNodeBs 110(1-12) are shown. Some of the elements described below may be referred to as "modules" or "logic." As referred to herein, "modules" or "logic" may describe hardware (such as a circuit), software (such as a program driver), or a combination thereof (such as a programmed micro-processing unit).

[0012] The E-UTRAN core network 104 includes a MME 106 to communicate with the eNodeBs 110(1-12). The MME 106 may serve as a key control -node for the system 100. For example, the MME 106 may be responsible for idle mode user equipment (UE) paging and tagging procedure, including retransmissions. The MME 106 may also be involved in the bearer activation/deactivation process and may also be responsible for intra-LTE handover operations. In some examples, the MME 106 may be capable of supporting a low power operation in the UE 120 when a UE 120 is capable of supporting such an operation.

[0013] The eNodeBs 110(1-12) may fall within one or more designated tracking areas 112(1-3). The eNodeBs 110(1-12) may include macro eNodeBs and/or low power (LP) eNodeBs. As used herein, the term "LP eNodeB" refers to any suitable relatively low power eNodeB for implementing a narrower cell (i.e., narrower than a macro cell) such as a femtocell, a picocell, or a micro cell at the edge of the network. Any of the eNodeBs 110(1-12) may be capable of terminating an air interface protocol and may be the first point of contact for the UE 120. In this example, the UE 120 is within the coverage area of the serving eNodeB 110(4). In some embodiments, any of the eNodeBs 110(1-12) may fulfill various logical functions for the system 100, including (but not limited to) radio network controller (RNC) functions (e.g., such as radio bearer management, uplink and downlink dynamic radio resource management and data packet scheduling) and mobility management. One or more of the eNodeBs 110(1-12) may be capable of supporting low power mode capability of the UE 120.

[0014] The UE 120 may include a modem, a low-power wake-up receiver (LP- WUR), an antenna, and a host subsystem. The UE 120 may also optionally include a location tracking circuit to track a location of the UE 120, such as via a global positioning system (GPS) receiver. The modem of the UE 120 may be configured to communicate using Orthogonal Frequency-Division Multiplexing (OFDM) communication signals with any of the eNodeBs 110(1-12) over a multicarrier communication channel in accordance various communication techniques, such as an Orthogonal Frequency-Division Multiple Access (OFDMA) communication technique or a Single Carrier Frequency Division Multiple Access (SC-FDMA) communication technique, although the scope of the embodiments is not limited in this respect. The OFDM signals can comprise a plurality of orthogonal subcarriers. In some embodiments, the UE 120 may be configured to determine a synchronization reference time based on reception of one or more signals from any of the eNodeBs 110(1-12). The UE 120 may also be configured to support device-to-device (D2D) communication with other UEs using OFDMA, SC- FDMA, or other multiple access schemes. The LP-WUR of the UE 120 may be configured to receive simply encoded (e.g., modulated) narrow band signals from the eNodeBs 110(1-12). The host subsystem may be configured to process data received from the eNodeBs 110(1-12) and to generate data to be provided to the eNodeBs 110(1-12).

[0015] In operation, the system 100 may user a cellular network to facilitate communication with the UE 120. By their very nature, cellular networks facilitate mobility of UEs from one area to another. To save power, some cellular standards allow the UE 120 to enter a power savings mode after a period of inactivity, and to "wake up" upon receiving an indication that new downlink data is available for the UE via a downlink channel (e.g., a physical downlink control channel (PDCCH)). For example, the 3GPP LTE and LTE-A standards define a paging operation by which a UE that has available downlink data is requested to "wake up" from a radio resource control (RRC) idle (RRC Idle) state that "wakes up" a UE in the RRC Idle state. However, in order to be responsive to a paging signal, the modem of the UE may have to at least periodically connect to the PDCCH channel to detect whether a paging signal is being transmitted. In some examples, LTE or LTE-A cellular modems may consume a large percentage of energy performing paging operations (e.g., some studies have indicated an average of 10% of total smart phone batter consumption) even when not connected to the cellular network. [0016] In accordance with some embodiments of this disclosure, the UE 120 may send a signal to the serving eNodeB 110(4) indicating a capability to support a low power mode (e.g., an indication that the UE 120 has the LP-WUR). The system 100 may then implement the low power mode by which the UE 120 may disable its modem and forego paging operations when in an RRC Idle state when in the coverage area of an eNodeB of the eNodeBs 110(1-12) capable of supporting the lower power mode. Instead, to support the low power mode, the LP-WUR of the UE 120 may receive "wake-up" messages on a downlink channel (e.g., via a narrow band signal) indicating new downlink data is available for the UE 120. In this example, when the UE 120 has downlink data available, the MME 106 may look up the UE 120 and determine the UE 120 is in the RRC Idle state. Responsive to determining that the UE 120 is in the RRC Idle state, the MME 106 may determine the tracking area covering the UE 120 and also determine whether it is capable of supporting the low power operation (e.g., has the LP- WUR). The MME 106 may provide a notification message (e.g., a modified Sl- AP message) to eNodeBs of the eNodeBs 110(1-12) that fall within the tracking area 112(1) associated with the UE 120 (e.g., the eNodeBs 110(1-8)) to inform the eNodeBs that the UE 120 has available downlink data. Responsive to receiving the notification message, the eNodeBs 110(1-8) may provide the 'wake-up" message via the downlink channel. The UE 120 may receive the "wake-up" message from the serving eNodeB 110(4) and initiate a wake-up operation to retrieve the downlink data from the PDCCH.

[0017] However, because of the anticipated mobility of the UE 120, the low power mode has to account for the possibility of a transition from a coverage area of the serving eNodeB 110(4) to a coverage area of another eNodeB of the eNodeBs 110(1-12). That is, the UE 120 may monitor when it has moved out of the coverage area of the serving eNodeB 110(4) while in the RRC Idle state (e.g., including the modem remaining disconnected).

[0018] In one example, the LP-WUR may determine when the UE 120 has left the coverage area of the serving eNodeB 110(4) by monitoring a wake-up receiver-specific sync signal (WURSSS) provided on a downlink channel by the serving eNodeB 110(4). In one example implementation, each of the eNodeBs 110(1-12) may provide (via a transceiver configured by processing circuitry) (e.g., broadcast) a WURSSS in a narrow-band signal on the downlink channel having a unique identifier. The broadcast of the respective WURSSSs by the eNodeBs 110(1-12) may vary by frequency, time, or a combination thereof, to, for example, prevent conflicts. In some examples, the adjacent eNodeBs may have different unique identifiers to avoid conflicts in the WURSSSs and allow the UE 120 to distinguish between WURSSSs. The WURSSS may include a preamble and the uniquely encoded identifier. In an example, the LTE or LTE-A Physical-layer Cell ID may be used as the unique identifier. The LTE or LTE-A specification defines a sequence of 504 unique Physical-layer Cell IDs (e.g., divided into 168 identity groups of three IDs) that are also unique Zadoff-Chu sequences. Each of the eNodeBs 110(1-12) is assigned a unique one of the Physical-layer Cell IDs. The eNodeBs 110(1-12) may encode and provide the Physical-layer Cell IDs or the ID of the Zadoff-Chu sequence in the WURSSS. The encoding may be performed using the following equation:

[0019] NIDc _ELL = 3 * NIDi + NID ₂

[0020] Where NIDCELL is a 9-bit encoded unique identifier, NIDi is a number in the range of 0 to 167 representing the identity group, and NID2 is a number in the range of 0 to 2 representing the specific ID within the identity group. Responsive to receiving the WURSSS from the serving eNodeB 110(4), the UE 120 may remain in the RRC Idle state when the unique identifier remains the same. Responsive to lack of receipt of the WURSSS signal for a predetermined of time (e.g., because an adjacent cell does not support the LP-WUR capability or provides the WURSSS signal at a different time/frequency) or responsive to detection that the unique identifier has changed, the LP-WUR triggers the wake- up of the main modem that is capable of reading the PDCCH channel to determine which of the above conditions has come to pass. After reading the PDCCH (or being unable to do so), the modem (e.g. an LTE modem) may trigger a cell reselection procedure or discover the eNodeB does not support LP-WUR capability or find that the UE is in an area where there is no LTE coverage available, etc. In case cell reselection is triggered, and the new eNodeB also supports LP-WUR capability, but sends the sync signal at a different time than what the LP-WUR is expecting, the modem acquires all such pertinent information and passes them to the LP-WUR so it can detect the new WURSSS, if available.

[0021] In another example, the WURSSSs provided by the eNodeBs 110(1-12) may lack the unique identifier, and the LP-WUR of the UE 120 may determine when it has left the serving eNodeB 110(4) by tracking signal strength (e.g., RSSI) transitions for received WURSSSs via the downlink channel at a certain predefined frequency and time period which are provided to the LP-WUR by the modem. That is, certain signal strength transitions may be indicative of receiving a different WURSSS from a different eNodeB than the previously received WURSSS from the serving eNodeB 110(4). For example, if the WURSSS is trending weaker and then starts trending stronger, the LP-WUR may determine that it is receiving a WURSSS from a different eNodeB. Further, if the LP-WUR determines that the signal strength falls below a minimum threshold, the LP-WUR may determine that the UE 120 is outside the coverage area of the serving eNodeB 110(4). Responsive to determining the LP-WUR has left the serving eNodeB 110(4) based on signal strength, the LP-WUR may trigger the cell reselection procedure, which may cause the modem of the UE 120 to "wake-up" (e.g., exit the RRC Idle state and enter a RRC Connected state) for a cell reselection procedure. In another example, rather than using separate WURSSSs, the signal strength transitions of the preambles of the "wake-up" signals sent to other UEs may be tracked to determine when the UE 120 has left the coverage area of the serving cell 110(4).

[0022] In another example, the UE 120 may include a location tracking circuit (e.g., a GPS receiver) that is capable of tracking the location of the UE 120 when in the RRC Idle state. Responsive to determining that the UE 120 has likely left the coverage area of the serving eNodeB 110(4), the host subsystem of the UE 120 may trigger a cell reselection, which may cause the modem of the UE 120 to "wake-up" (e.g., exit the RRC Idle state and enter a RRC Connected state) for a cell reselection procedure. In some examples, the location tracking may be used in conjunction with the LP-WUR to supplement the LP-WUR for eNodeBs of the eNodeBs 110(1-12) that to not support the LP-WUR for mobility management. The periodicity of the location tracking by the location tracking circuit may be similar to the periodicity that the modem is required to perform a cell selection/reselection procedure so as not to cause additional power consumption in the UE 120 for this function.

[0023] The ability of the UE 120 to monitor mobility while allowing the modem of the UE 120 to remain disconnected while in the RRC Idle state may reduce power consumption (e.g., and extend battery life) as compared with the modem periodically waking up and connecting to the serving eNodeB 110(4) to determine a location of the UE 120 and whether downlink data is available. It will be appreciated that, while the system 100 depicted in FIG. 1 includes twelve of the eNodeBs 110(1-12), the system 100 may include any number of eNodeBs. Further, while the UE 120 is depicted in the coverage area associated with the serving eNodeB 110(4), the UE 120 could be in the coverage area associated with any eNodeB of the system 100. Lastly, the functions performed by the LP-WUR, modem, location tracking circuitry, etc. of the UE 120 may be configured by processing circuitry of the UE 120.

[0024] FIG. 2 illustrates an architecture of components of a cellular network system 200, in accordance with some embodiments of the disclosure. In this example, the system 200 may operate using an LTE network, and may include a UE 220 to communicate with an eNodeB (not shown). In this illustration, only a portion of the components of the UE 220 are shown. Some of the elements described below may be referred to as "modules" or "logic." As referred to herein, "modules" or "logic" may describe hardware (such as a circuit), software (such as a program driver), or a combination thereof (such as a programmed microprocessing unit). The UE 220 may be implemented in the UE 120 of FIG. 1.

[0025] The UE 220 may include a host subsystem 222 communicatively coupled to a modem 224. The UE 220 may further include a LP-WUR 226 coupled to the modem 224. The modem 224 may be a LTE or LTE-A modem. The UE 220 may further include antennas 229 to provide communication between an eNodeB and the modem 224 and LP-WUR 226. The UE 220 may also optionally include a location tracking circuit 228 to track a location of the UE 220, such as a GPS receiver. The modem 224 may be configured to communicate using Orthogonal Frequency-Division Multiplexing (OFDM) communication signals with any of the eNodeBs over a multicarrier communication channel in accordance various communication techniques, such as an Orthogonal Frequency-Division Multiple Access (OFDMA) communication technique or a Single Carrier Frequency Division Multiple Access (SC-FDMA) communication technique, although the scope of the embodiments is not limited in this respect. The OFDM signals can comprise a plurality of orthogonal subcarriers. In some embodiments, the UE 120 may be configured to determine a synchronization reference time based on reception of one or more signals from the eNodeBs. The UE 220 may also be configured to support device-to-device (D2D) communication with other UEs using OFDMA, SC-FDMA, or other multiple access schemes. The LP-WUR 226 may be configured to receive narrow-band signals via a downlink channel from the eNodeBs. The host subsystem 222 may be configured to process data received from the eNodeBs and to generate data to be provided to the eNodeBs.

[0026] In operation, the system 200 may use a cellular network to facilitate communication with the UE 220. In accordance with some embodiments of this disclosure, the UE 220 may send a signal to the serving eNodeB indicating a capability to support the low power mode (e.g., that the UE 220 includes the LP- WUR 226). The system 200 may implement a low power mode by which the modem 224 may be disabled (e.g., disconnected from the serving eNodeB) and forego paging operations when in an RRC Idle state. Instead, to support the low power mode, the LP-WUR 226 may receive "wake-up" messages on a downlink channel (e.g., via a narrow band signal) indicating new downlink data is available for the UE 220. In this example, when the UE 220 has downlink data available, the LP-WUR 226 may receive the "wake-up" message from the serving eNodeB and initiate a wake-up operation to retrieve the downlink data from a PDCCH.

[0027] However, because of the anticipated mobility of the UE 220, the low power mode has to account for the possibility of a transition from a coverage area of the serving eNodeB to a coverage area of another eNodeB. That is, the UE 220 may monitor when it has moved out of the coverage area of the serving eNodeB while in the RRC Idle state (e.g., including the modem remaining disconnected). In one example, each of the eNodeBs provide (e.g., broadcast) a WURSSS in a narrow-band signal having a unique identifier. The WURSSSs may be encoded/decoded using on-off keying (OOK), phase-shift keying (PSK), or another simple modulation scheme. Adjacent eNodeBs may have different unique identifiers to avoid conflicts in the WURSSSs and allow the UE 120 to distinguish between WURSSSs. The WURSSS may include a preamble and the unique identifier. In an example, the LTE or LTE-A Physical-layer Cell ID may be used as the unique identifier. The LTE or LTE-A specification defines a sequence of 504 unique Physical-layer Cell IDs (e.g., divided into 168 identity groups of three IDs) that are also unique Zadoff-Chu sequences. Each of the eNodeBs 110(1-12) is assigned a unique one of the Physical-layer Cell IDs. The eNodeBs 110(1-12) may encode and provide the Physical-layer Cell IDs or the ID of the Zadoff-Chu sequence in the WURSSS. The encoding may be performed using the following equation:

[0028] NIDc _ELL = 3 * NID _X + NID ₂

[0029] Where NIDCELL is a 9-bit encoded unique identifier, NIDi is a number in the range of 0 to 167 representing the identity group, and NID2 is a number in the range of 0 to 2 representing the specific ID within the identity group. Responsive to receiving the WURSSS from the serving eNodeB, the LP-WUR 226 allow the UE 220 to remain in the RRC Idle state when the unique identifier remains the same. Responsive to lack of receipt of the WURSSS signal for a predetermined of time (e.g., because an adjacent cell does not support the LP-WUR 226 capability or transits the WURSSS signal at a different time/frequency) or responsive to detection that the unique identifier has changed, the LP-WUR 226 may trigger the cell reselection procedure, which may cause the modem of the UE 220 to "wake- up" (e.g., wake up the modem 224) for the cell reselection procedure (e.g., read the system information block (SIB) messages that are broadcast by the eNodeB to determine whether the eNodeB supports the LP-WUR signaling) and to adjust parameters for the LP-WUR 226 to detect the new WURSSS, if available.

[0030] In another example, the WURSSSs provided by the eNodeBs may lack the unique identifier, and the LP-WUR 226 may determine when it has left the serving eNodeB by tracking signal strength (e.g., RSSI) transitions for received WURSSSs via the downlink channel. Thus, the LP-WUR 226 may use tracked signal strength transitions of the WURSSSs to determine when it has left the serving cell. That is, certain signal strength transitions may be indicative of receiving a different WURSSS from a different eNodeB than the previously received WURSSS from the serving eNodeB. For example, if the WURSSS is trending weaker and then starts trending stronger, the LP-WUR 226 may determine that it is receiving a WURSSS from a different eNodeB. Further, if the LP-WUR 226 determines that the signal strength falls below a minimum threshold, the LP-WUR 226 may determine that the UE 220 is outside the coverage area of the serving eNodeB. Responsive to determining the UE 220 has left the coverage area of the serving eNodeB, the LP-WUR 226 may trigger the cell reselection procedure, which may cause the modem of the UE 120 to "wake- up" (e.g., exit the RRC Idle state and enter a RRC Connected state) for the cell reselection procedure. In another example, rather than having separate WURSSSs, the LP-WUR 226 may track the signal strength transitions of the preambles of the "wake-up" signals sent to other UEs to determine when the UE 220 has left the coverage area of the serving cell. In time-division duplex, the modem 224 may configure a timer in the LP-WUR 226 to allow the LP-WUR 226 to have a rough estimate of when a downlink transmission will occur.

[0031] In another example, the location tracking circuit 228 of the UE 220 may track a location of the UE 220 when in the RRC Idle state. The location tracking circuit 228 may compare a current location to a coverage area of the serving eNodeB (e.g., from eNodeB coverage area information stored in a database). Responsive to a determination by the location tracking circuit 228 that the UE 220 has left the coverage area of the serving eNodeB, the location tracking circuit 228 may provide a cell reselection signal to the host subsystem 222 to indicate a reselection process is necessary, and the host subsystem 222 may trigger the cell reselection procedure, which may cause the modem of the UE 120 to "wake-up" (e.g., exit the RRC Idle state and enter a RRC Connected state) for the cell reselection procedure. In some examples, the location tracking may be used in conjunction with the LP-WUR 226 to supplement the LP-WUR 226 for eNodeBs that to not support the LP-WUR 226 for mobility management. The periodicity of the location tracking by the location tracking circuit 228 may be similar to the periodicity that the modem 224 is required to perform a cell selection/reselection procedure so as not to cause additional power consumption in the UE 220 for this function.

[0032] The ability of the UE 220 to monitor mobility while allowing the modem of the UE 220 to remain disconnected while in the RRC Idle state may reduce power consumption (e.g., and extend battery life) as compared with the modem periodically waking up and connecting to the serving eNodeB to determine a location of the UE 220 and whether downlink data is available. The functions performed by the LP-WUR 226, the modem 224, location tracking circuitry 228, etc. of the UE 220 may be configured by processing circuitry of the UE 220.

[0033] FIG. 3 illustrates a flow diagram of a method 300 to manage mobility in a low power mode in accordance with some embodiments of the disclosure. The method 300 may be implemented in the UE 120 of FIG. 1, the UE 220 of FIG. 2, or combinations thereof.

[0034] The method 300 may include entering a low power mode that includes entry into a radio resource control idle (RRC Idle) state and to cease monitoring a physical control downlink control channel (PDCCH) of a serving evolved node B (eNodeB) in response to a period of inactivity, at 310. The eNodeB may include the serving eNodeB 110(4) of FIG. 1.

[0035] The method 300 may further include, in response to receipt of a cell reselection signal from a low-power wake-up receiver (LP-WUR), exiting the low power mode, and initiating a cell reselection procedure, at 320. The LP-WUR may include an LP-WUR of the UE 110 of FIG. 1 or the LP-WUR 226 of FIG. 2. In some examples, the method 300 may further include generating signal data to be transmitted to an eNodeB indicating the user equipment is capable of supporting the low power mode. The method 300 may further include, in response to triggering of the cell reselection procedure based on data from a location tracking circuit, exiting the low power mode, and initiating a cell reselection procedure. The location tracking circuit may include the location tracking circuit 228 of FIG. 2.

[0036] The method 300 may further include, in response to receipt of a wake-up signal from the LP-WUR, exiting the low power mode, and initiate a monitoring of a physical downlink control channel to retrieve downlink data.

[0037] FIG. 4 illustrates a flow diagram of a method 400 to manage mobility in a low power mode in accordance with some embodiments of the disclosure. The method 300 may be implemented in any of the eNodeBs 110(1-12) of FIG. 1.

[0038] The method 400 may include receiving an indication that a user equipment is capable of supporting a low power mode, at 410. The user equipment may include the UE 120 of FIG. 1, the UE 220 of FIG. 2, or combinations thereof. The indication may be received from the user equipment or from a mobility management entity (e.g., the MME 106 of FIG. 1).

[0039] The method 400 may further include receiving a signal from a user equipment that indicates the user equipment includes a low power wake-up receiver (LP-WUR) to support a low power mode that allows the user equipment to enter a radio resource control idle (RRC Idle) state and cease monitoring a physical control downlink control channel (PDCCH), at 420. Encoding the WURSSS may include encoding the WURSSS with a preamble. Encoding the WURSSS may further include encoding the WURSSS with a unique identifier. The unique identifier may include an LTE or LTE-A Physical -layer Cell ID or an identifier of a Zadoff-Chu sequence associated with an LTE/LTE-A Physical- layer Cell ID.

[0040] The method 400 may further include periodically providing the WURSSS in a narrow band signal on a downlink channel to the LP-WUR of the user equipment, at 430.

[0041] The method 400 may further include receiving a notification message from a mobility management entity to that downlink data is available for the user equipment, and providing a wake-up message to the LP-WUR of the user equipment in response to receiving the notification message. The mobility management entity may include the MME 106 of FIG. 1.

[0042] Embodiments described herein may be implemented into a system using any suitably configured hardware and/or software. FIG. 5 illustrates a block diagram of components of a User Equipment (UE) device 500 according to embodiments of the disclosure. The UE 500 may be implemented in the UE 120 of FIG. 1, the UE 220 of FIG. 2, or combinations thereof. The UE 500 may be configured to implement the method 300 of FIG. 3. In some embodiments, the UE device 500 may include application circuitry 502, baseband circuitry 504, Radio Frequency (RF) circuitry 506, front-end module (FEM) circuitry 508, a low-power wake-up receiver (LP-WUR) 550 and one or more antennas 510, coupled together at least as shown.

[0043] The application circuitry 502 may include one or more application processors. For example, the application circuitry 502 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.

[0044] The baseband circuitry 504 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The baseband circuitry 504 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 506 and to generate baseband signals for a transmit signal path of the RF circuitry 506. Baseband processing circuity 504 may interface with the application circuitry 502 for generation and processing of the baseband signals and for controlling operations of the RF circuitry 506. For example, in some embodiments, the baseband circuitry 504 may include a second generation (2G) baseband processor 504a, third generation (3G) baseband processor 504b, fourth generation (4G) baseband processor 504c, and/or other baseband processor(s) 504d for other existing generations, generations in development or to be developed in the future (e.g., fifth generation (5G), 6G, etc.). The baseband circuitry 504 (e.g., one or more of baseband processors 504a-d) may handle various radio control functions that enable communication with one or more radio networks via the RF circuitry 506. 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 504 may include Fast-Fourier Transform (FFT), precoding, and/or constellation mapping/demapping functionality. In some embodiments, encoding/decoding circuitry of the baseband circuitry 504 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.

[0045] In some embodiments, the baseband circuitry 504 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) 504e of the baseband circuitry 504 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) 504f. The audio DSP(s) 504f 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 504 and the application circuitry 502 may be implemented together such as, for example, on a system on a chip (SOC).

[0046] In some embodiments, the baseband circuitry 504 may provide for communication compatible with one or more radio technologies. For example, in some embodiments, the baseband circuitry 504 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 504 is configured to support radio communications of more than one wireless protocol may be referred to as multi-mode baseband circuitry.

[0047] RF circuitry 506 may enable communication with wireless networks using modulated electromagnetic radiation through a non-solid medium. In various embodiments, the RF circuitry 506 may include switches, filters, amplifiers, etc. to facilitate the communication with the wireless network. RF circuitry 506 may include a receive signal path which may include circuitry to down-convert RF signals received from the FEM circuitry 508 and provide baseband signals to the baseband circuitry 504. RF circuitry 506 may also include a transmit signal path which may include circuitry to up-convert baseband signals provided by the baseband circuitry 504 and provide RF output signals to the FEM circuitry 508 for transmission.

[0048] In some embodiments, the RF circuitry 506 may include a receive signal path and a transmit signal path. The receive signal path of the RF circuitry 506 may include mixer circuitry 506a, amplifier circuitry 506b and filter circuitry 506c. The transmit signal path of the RF circuitry 506 may include filter circuitry 506c and mixer circuitry 506a. RF circuitry 506 may also include synthesizer circuitry 506d for synthesizing a frequency for use by the mixer circuitry 506a of the receive signal path and the transmit signal path. In some embodiments, the mixer circuitry 506a of the receive signal path may be configured to down-convert RF signals received from the FEM circuitry 508 based on the synthesized frequency provided by synthesizer circuitry 506d. The amplifier circuitry 506b may be configured to amplify the down-converted signals and the filter circuitry 506c may be a low-pass filter (LPF) or band-pass 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 504 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 506a of the receive signal path may comprise passive mixers, although the scope of the embodiments is not limited in this respect.

[0049] In some embodiments, the mixer circuitry 506a of the transmit signal path may be configured to up-convert input baseband signals based on the synthesized frequency provided by the synthesizer circuitry 506d to generate RF output signals for the FEM circuitry 508. The baseband signals may be provided by the baseband circuitry 504 and may be filtered by filter circuitry 506c. The filter circuitry 506c may include a low-pass filter (LPF), although the scope of the embodiments is not limited in this respect.

[0050] In some embodiments, the mixer circuitry 506a of the receive signal path and the mixer circuitry 506a 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 506a of the receive signal path and the mixer circuitry 506a 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 506a of the receive signal path and the mixer circuitry 506a may be arranged for direct downconversion and/or direct upconversion, respectively. In some embodiments, the mixer circuitry 506a of the receive signal path and the mixer circuitry 506a of the transmit signal path may be configured for super-heterodyne operation.

[0051] 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 506 may include analog- to-digital converter (ADC) and digital-to-analog converter (DAC) circuitry and the baseband circuitry 504 may include a digital baseband interface to communicate with the RF circuitry 506.

[0052] 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.

[0053] In some embodiments, the synthesizer circuitry 506d may be a fractional- N synthesizer or a fractional N/N+l 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 506d may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer comprising a phase-locked loop with a frequency divider.

[0054] The synthesizer circuitry 506d may be configured to synthesize an output frequency for use by the mixer circuitry 506a of the RF circuitry 506 based on a frequency input and a divider control input. In some embodiments, the synthesizer circuitry 506d may be a fractional N/N+l synthesizer.

[0055] 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 504 or the applications processor 502 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 502.

[0056] Synthesizer circuitry 506d of the RF circuitry 506 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 (DP A). In some embodiments, the DMD may be configured to divide the input signal by either N or N+l (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.

[0057] In some embodiments, synthesizer circuitry 506d 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 506 may include an IQ/polar converter. In some embodiments, the RF circuitry 506 may include a ΜΊΜΟ transceiver.

[0058] FEM circuitry 508 may include a receive signal path which may include circuitry configured to operate on RF signals received from one or more antennas 510, amplify the received signals and provide the amplified versions of the received signals to the RF circuitry 506 for further processing. FEM circuitry 508 may also include a transmit signal path which may include circuitry configured to amplify signals for transmission provided by the RF circuitry 506 for transmission by one or more of the one or more antennas 510.

[0059] In some embodiments, the FEM circuitry 508 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 506). The transmit signal path of the FEM circuitry 508 may include a power amplifier (PA) to amplify input RF signals (e.g., provided by RF circuitry 506), and one or more filters to generate RF signals for subsequent transmission (e.g., by one or more of the one or more antennas 510). The FEM may be implemented in the modem 224 of FIG. 2

[0060] The LP-WUR 550 is a low-power radio separate from the FEM 508. The LP-WUR 550 may remain awake continuously (or at high-frequency intervals) and monitor for "wake-up" and WURSSSs via one or more of the one or more antennas 510, allowing the FEM 550 to remain powered down in the absence of downlink data. When the LP-WUR 550 detects the "wake-up" and WURSSSs, the LP-WUR 550 may be configured to wake up the FEM 508 to receive incoming downlink data. The LP-WUR 550 may be implemented in the LP-WUR 226 of FIG. 2.

[0061] In some embodiments, a simple radio waveform (e.g., a narrow-band wake-up signal comprising an on-off key (OOK) modulated tone) may be used to signal pending downlink data for the UE 500, rather than a highly complex OFDM having the precise synchronization characteristics of a standard LTE channel. This simple waveform allows for the LP-WUR 550 to remain awake and still consume less power than the FEM 508, thereby significantly increasing the battery life of the UE 500.

[0062] In some embodiments, the UE device 500 may include additional elements such as, for example, memory/storage, display, camera, sensor, and/or input/output (I/O) interface.

[0063] FIG. 6 illustrates generally an example of a block diagram of a machine 600 upon which any one or more of the techniques (e.g., methodologies) discussed herein can perform in accordance with some embodiments. In alternative embodiments, the machine 600 can operate as a standalone device or can be connected (e.g., networked) to other machines. In a networked deployment, the machine 600 can operate in the capacity of a server machine, a client machine, or both in server-client network environments. In an example, the machine 600 can act as a peer machine in peer-to-peer (P2P) (or other distributed) network environment. The machine 600 can be a personal computer (PC), a tablet PC, a set-top box (STB), a personal digital assistant (PDA), a mobile telephone, a web appliance, a network router, switch or bridge, or any machine capable of executing instructions (sequential or otherwise) that specify actions to be taken by that machine. Further, while only a single machine is illustrated, the term "machine" shall also be taken to include any collection of machines that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein, such as cloud computing, software as a service (SaaS), other computer cluster configurations.

[0064] Examples, as described herein, can include, or can operate on, logic or a number of components, modules, or mechanisms. Modules are tangible entities (e.g., hardware) capable of performing specified operations when operating. A module includes hardware. In an example, the hardware can be specifically configured to carry out a specific operation (e.g., hardwired). In an example, the hardware can include configurable execution units (e.g., transistors, circuits, etc.) and a computer readable medium containing instructions, where the instructions configure the execution units to carry out a specific operation when in operation. The configuring can occur under the direction of the executions units or a loading mechanism. Accordingly, the execution units are communicatively coupled to the computer readable medium when the device is operating. In this example, the execution units can be a member of more than one module. For example, under operation, the execution units can be configured by a first set of instructions to implement a first module at one point in time and reconfigured by a second set of instructions to implement a second module.

[0065] Machine (e.g., computer system) 600 can include a hardware processor 602 (e.g., a central processing unit (CPU), a graphics processing unit (GPU), a hardware processor core, or any combination thereof), a main memory 604 and a static memory 606, some or all of which can communicate with each other via an interlink (e.g., bus) 608. The machine 600 can further include a display unit 610, an alphanumeric input device 612 (e.g., a keyboard), and a user interface (UI) navigation device 614 (e.g., a mouse). In an example, the display unit 610, alphanumeric input device 612 and UI navigation device 614 can be a touch screen display. The machine 600 can additionally include a storage device (e.g., drive unit) 616, a signal generation device 618 (e.g., a speaker), a network interface device 620, and one or more sensors 621, such as a global positioning system (GPS) sensor, compass, accelerometer, or other sensor. The machine 600 can include an output controller 628, such as a serial (e.g., universal serial bus (USB), parallel, or other wired or wireless (e.g., infrared (IR), near field communication (NFC), etc.) connection to communicate or control one or more peripheral devices (e.g., a printer, card reader, etc.).

[0066] The storage device 616 can include a machine readable medium 622 that is non-transitory on which is stored one or more sets of data structures or instructions 624 (e.g., software) embodying or utilized by any one or more of the techniques or functions described herein. The instructions 624 can also reside, completely or at least partially, within the main memory 604, within static memory 606, or within the hardware processor 602 during execution thereof by the machine 600. In an example, one or any combination of the hardware processor 602, the main memory 604, the static memory 606, or the storage device 616 can constitute machine readable media.

[0067] While the machine readable medium 622 is illustrated as a single medium, the term "machine readable medium" can include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) configured to store the one or more instructions 624.

[0068] The term "machine readable medium" can include any medium that is capable of storing, encoding, or carrying instructions for execution by the machine 600 and that cause the machine 600 to perform any one or more of the techniques of the present disclosure, or that is capable of storing, encoding or carrying data structures used by or associated with such instructions. Non-limiting machine readable medium examples can include solid-state memories, and optical and magnetic media. In an example, a massed machine readable medium comprises a machine readable medium with a plurality of particles having invariant (e.g., rest) mass. Accordingly, massed machine-readable media are not transitory propagating signals. Specific examples of massed machine readable media can include: non-volatile memory, such as semiconductor memory devices (e.g., Electrically Programmable Read-Only Memory (EPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM)) and flash memory devices; magnetic disks, such as internal hard disks and removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks.

[0069] The instructions 624 can further be transmitted or received over a communications network 626 using a transmission medium via the network interface device 620 utilizing any one of a number of transfer protocols (e.g., frame relay, internet protocol (IP), transmission control protocol (TCP), user datagram protocol (HDP), hypertext transfer protocol (HTTP), etc.). Example communication networks can include a local area network (LAN), a wide area network (WAN), a packet data network (e.g., the Internet), mobile telephone networks (e.g., cellular networks), Plain Old Telephone (POTS) networks, and wireless data networks (e.g., Institute of Electrical and Electronics Engineers (IEEE) 802.11 family of standards known as Wi-Fi®, IEEE 802.16 family of standards known as WiMax®), IEEE 802.15.4 family of standards, peer-to-peer (P2P) networks, among others. In an example, the network interface device 620 can include one or more physical jacks (e.g., Ethernet, coaxial, or phone jacks) or one or more antennas to connect to the communications network 626. In an example, the network interface device 620 can include a plurality of antennas to wirelessly communicate using at least one of single-input multiple-output (SIMO), multiple-input multiple-output (MTMO), or multiple-input single-output (MISO) techniques. The term "transmission medium" shall be taken to include any intangible medium that is capable of storing, encoding or carrying instructions for execution by the machine 600, and includes digital or analog communications signals or other intangible medium to facilitate communication of such software.

[0070] In some examples, FIGs. 5 and 6 may also illustrate components of an eNodeB, such as any of the eNodeBs 110(1-12) of FIG. 1. As used herein, the term "circuitry" may refer to, be part of, or include an Application Specific Integrated Circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group), and/or memory (shared, dedicated, or group) that execute one or more software or firmware programs, a combinational logic circuit, and/or other suitable hardware components that provide the described functionality. In some embodiments, the circuitry may be implemented in, or functions associated with the circuitry may be implemented by, one or more software or firmware modules. In some embodiments, circuitry may include logic, at least partially operable in hardware.

[0071] Additional Notes & Examples:

[0072] Example 1 is an apparatus of User Equipment (UE), the apparatus comprising: memory; and processing circuitry, the processing circuitry to: configure a low power wake-up receiver (LP-WUR) to monitor a downlink channel for a wake-up receiver-specific sync signal (WURSSS) from a serving evolved node B (eNodeB), the WURSSS transmitted in a narrow-band signal; in response to a period of inactivity, configure a modem, to enter a low power mode that includes entry into a radio resource control idle (RRC Idle) state and to cease monitoring a physical downlink control channel (PDCCH) of the serving eNodeB; configure the LP -WUR to trigger a cell reselection in response to a determination that the apparatus is no longer covered by the serving eNodeB based on the WURSSS; and in response to the trigger of the cell reselection by the LP -WUR, configure the modem to exit the RRC Idle state and trigger a cell reselection procedure.

[0073] In Example 2, the subject matter of Example 1 optionally includes wherein the processing circuitry is further to configure the modem to provide a signal that indicates the user equipment includes the LP -WUR to support the low power mode.

[0074] In Example 3, the subject matter of any one or more of Examples 1-2 optionally include wherein the processing circuitry is further to configure the LP- WUR to decode the WURSSS to retrieve a retrieved unique identifier and to compare the retrieved unique identifier to a unique identifier associated with the serving eNodeB, wherein the cell reselection triggered in response to the retrieved unique identifier being different than the unique identifier associated with the serving eNodeB.

[0075] In Example 4, the subject matter of Example 3 optionally includes wherein the retrieved unique identifier includes an LTE or LTE-A Physical -layer Cell ID.

[0076] In Example 5, the subject matter of any one or more of Examples 3-4 optionally include wherein the retrieved unique identifier includes an identifier of a Zadoff-Chu sequence associated with an LTE or LTE-A Physical-layer Cell ID.

[0077] In Example 6, the subject matter of any one or more of Examples 1-5 optionally include wherein the processing circuitry to configure the LP -WUR to trigger the cell reselection in response to lack of receipt of the WURSSS for a predetermined period of time.

[0078] In Example 7, the subject matter of any one or more of Examples 1-6 optionally include wherein the processing circuitry to configure the LP -WUR to track transitions of a signal strength of the WURSSS and to trigger the cell reselection in response to the transitions of the tracked signal strength indicating the apparatus is no longer covered by the serving eNodeB.

[0079] In Example 8, the subject matter of Example 7 optionally includes wherein the processing circuitry to configure the LP-WUR to trigger the cell reselection in response to the transitions of the signal strength of the WURSSS indicating an increase in strength after a period where the transitions of the signal strength of the WURSSS indicate a decrease in strength.

[0080] In Example 9, the subject matter of any one or more of Examples 7-8 optionally include wherein the processing circuitry to configure the LP-WUR to trigger the cell reselection in response to the signal strength of the WURSSS transitioning below a minimum threshold.

[0081] In Example 10, the subject matter of any one or more of Examples 7-9 optionally include wherein the tracked signal strength is a received signal strength indicator.

[0082] In Example 11, the subject matter of any one or more of Examples 1-10 optionally include a location tracking circuit to track a location, the location tracking circuit further to provide an indication that the apparatus is no longer covered by the serving eNodeB based on a tracked location; and a host subsystem to receive the indication that the apparatus is no longer covered by the serving eNodeB from the location tracking circuit and to trigger the cell reselection in response to the indication that the apparatus is no longer covered by the serving eNodeB from the location tracking circuit.

[0083] In Example 12, the subject matter of Example 11 optionally includes wherein the location tracking circuit includes a global positioning system receiver.

[0084] In Example 13, the subject matter of any one or more of Examples 1-12 optionally include wherein the LP-WUR decodes the WURSSS using an on-off keying decoder or a phase shift keying decoder.

[0085] In Example 14, the subject matter of any one or more of Examples 1-13 optionally include the LP-WUR; and the modem separate from the LP-WUR.

[0086] Example 15 is an apparatus of evolved Node B (eNodeB), the apparatus comprising: memory; and processing circuitry, the processing circuitry to configure a transceiver to: receive a signal from a user equipment that indicates the user equipment includes a low power wake-up receiver (LP-WUR) to support a low power mode that allows the user equipment to enter a radio resource control idle (RRC Idle) state and cease monitoring a physical downlink control channel (PDCCH); encode a wake-up receiver-specific sync signal (WURSSS), the WURSSS indicative of support for the low power mode by the eNodeB; and periodically provide theWURSSS in a narrow band signal on a downlink channel to the LP-WUR of the user equipment.

[0087] In Example 16, the subject matter of Example 15 optionally includes wherein to configure a transceiver to encode the WURSSS includes the processing circuitry to encode the WURSSS with a preamble.

[0088] In Example 17, the subject matter of any one or more of Examples 15-16 optionally include wherein to configure a transceiver to encode the WURSSS includes the processing circuitry to encode the WURSSS with a unique identifier.

[0089] In Example 18, the subject matter of Example 17 optionally includes wherein the unique identifier includes an LTE or LTE-A Physical-layer Cell ID.

[0090] In Example 19, the subject matter of any one or more of Examples 17-18 optionally include wherein the retrieved unique identifier includes an identifier of a Zadoff-Chu sequence associated with an LTE or LTE-A Physical-layer Cell ID.

[0091] In Example 20, the subject matter of any one or more of Examples 15-19 optionally include wherein the processing circuitry further to configure a transceiver to: receive a notification message from a mobility management entity to that downlink data is available for the user equipment; and provide a wake-up message to the LP-WUR of the user equipment in response to receiving the notification message.

[0092] Example 21 is a non-transitory computer-readable storage medium that stores instructions for execution by processing circuitry of a wireless communication device to configure the device to perform operations to: enter a low power mode that includes entry into a radio resource control idle (RRC Idle) state and to cease monitoring a physical downlink control channel (PDCCH) of a serving evolved node B (eNodeB) in response to a period of inactivity; and in response to a trigger of a cell reselection by a low-power wake-up receiver (LP- WUR): exit the low power mode; and initiate a cell reselection procedure. [0093] In Example 22, the subject matter of Example 21 optionally includes instructions, which when executed by the processing circuitry, cause the processing circuitry to perform operations to generate signal data to be transmitted to an eNodeB indicating a capability to support the low power mode.

[0094] In Example 23, the subject matter of any one or more of Examples 21-22 optionally include instructions, which when executed by the processing circuitry, cause the processing circuitry to perform operations to, in response to receipt of a wake-up signal from the LP-WUR: exit the low power mode; and initiate a monitoring of the PDDCH to retrieve downlink data.

[0095] In Example 24, the subject matter of any one or more of Examples 21-23 optionally include instructions, which when executed by the processing circuitry, cause the processing circuitry to perform operations to, in response to triggering of the cell reselection procedure based on data from a location tracking circuit: exit the low power mode; and initiate a cell reselection procedure.

[0096] Example 25 is a non-transitory computer-readable storage medium that stores instructions for execution by processing circuitry of a wireless communication device to configure the device to perform operations to: receive a signal from a user equipment that indicates the user equipment includes a low power wake-up receiver (LP-WUR) to support a low power mode that allows the user equipment to enter a radio resource control idle (RRC Idle) state and cease monitoring a physical downlink control channel (PDCCH); encode a wake-up receiver-specific sync signal (WURSSS), the WURSSS indicative of support for the low power mode by the eNodeB; and periodically provide the WURSSS in a narrow band signal on a downlink channel to the LP-WUR of the user equipment.

[0097] In Example 26, the subject matter of Example 25 optionally includes wherein to encode the WURSSS includes instructions, which when executed by the processing circuitry, cause the processing circuitry to perform operations to encode the WURSSS with a preamble.

[0098] In Example 27, the subject matter of any one or more of Examples 25-26 optionally include wherein to encode the WURSSS includes instructions, which when executed by the processing circuitry, cause the processing circuitry to perform operations encoding the WURSSS with a unique identifier. [0099] In Example 28, the subject matter of Example 27 optionally includes wherein the unique identifier includes an LTE or LTE-A Physical-layer Cell ID.

[00100] In Example 29, the subject matter of any one or more of Examples 27-28 optionally include wherein the retrieved unique identifier includes an identifier of a Zadoff-Chu sequence associated with an LTE or LTE-A Physical-layer Cell ID.

[00101] In Example 30, the subject matter of any one or more of Examples 25-29 optionally include instructions, which when executed by the processing circuitry, cause the processing circuitry to perform operations to: receive a notification message from a mobility management entity to that downlink data is available for the user equipment; and provide a wake-up message to the LP-WUR of the user equipment in response to receiving the notification message.

[00102] Example 31 is an apparatus comprising: means for entering a low power mode that includes entry into a radio resource control idle (RRC Idle) state and to cease monitoring a physical downlink control channel (PDCCH) of a serving evolved node B (eNodeB) in response to a period of inactivity; means for exiting the low power mode in response to a trigger of a cell reselection by a low-power wake-up receiver (LP-WUR); and means for initiating a cell reselection procedure in response to the trigger of the cell reselection by the LP-WUR and after exit of the low power mode.

[00103] In Example 32, the subject matter of Example 31 optionally includes means for generating signal data to be transmitted to an eNodeB indicating a capability to support the low power mode.

[00104] In Example 33, the subject matter of any one or more of Examples 31-32 optionally include means for exiting the low power mode in response to receipt of a wake-up signal from the LP-WUR; and means for initiating a monitoring of the PDDCH to retrieve downlink data in response to receipt of a wake-up signal from the LP-WUR after exit of the low power mode.

[00105] In Example 34, the subject matter of any one or more of Examples 31-33 optionally include means for exiting the low power mode in response to triggering of the cell reselection procedure based on data from a location tracking circuit; and means for initiating a cell reselection procedure in response to receipt of a wake-up signal from the LP-WUR after exit of the low power mode. [00106] Example 35 is an apparatus comprising: means for receiving a signal from a user equipment that indicates the user equipment includes a low power wake-up receiver (LP-WUR) to support a low power mode that allows the user equipment to enter a radio resource control idle (RRC Idle) state and cease monitoring a physical downlink control channel (PDCCH); means for encoding a WURSSS, the WURSSS indicative of support for the low power mode by an eNodeB; and means for periodically providing a WURSSS in a narrow band signal on a downlink channel to the LP-WUR of the user equipment.

[00107] In Example 36, the subject matter of Example 35 optionally includes wherein means for encoding the WURSSS includes means for encoding the WURSSS with a preamble.

[00108] In Example 37, the subject matter of any one or more of Examples 35-36 optionally include wherein means for encoding the WURSSS includes means for encoding the WURSSS with a unique identifier.

[00109] In Example 38, the subject matter of Example 37 optionally includes wherein the unique identifier includes an LTE or LTE-A Physical-layer Cell ID.

[00110] In Example 39, the subject matter of any one or more of Examples 37-38 optionally include wherein the retrieved unique identifier includes an identifier of a Zadoff-Chu sequence associated with an LTE or LTE-A Physical-layer Cell ID.

[00111] In Example 40, the subject matter of any one or more of Examples 35-39 optionally include means for receiving a notification message from a mobility management entity to that downlink data is available for the user equipment; and means for providing a wake-up message to the LP-WUR of the user equipment in response to receiving the notification message.

[00112] The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments that may be practiced. These embodiments are also referred to herein as "examples." Such examples may include elements in addition to those shown or described. However, also contemplated are examples that include the elements shown or described. Moreover, also contemplate are examples using any combination or permutation of those elements shown or described (or one or more aspects thereof), either with respect to a particular example (or one or more aspects thereof), or with respect to other examples (or one or more aspects thereof) shown or described herein.

[00113] Publications, patents, and patent documents referred to in this document are incorporated by reference herein in their entirety, as though individually incorporated by reference. In the event of inconsistent usages between this document and those documents so incorporated by reference, the usage in the incorporated reference(s) are supplementary to that of this document; for irreconcilable inconsistencies, the usage in this document controls.

[00114] In this document, the terms "a" or "an" are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of "at least one" or "one or more." In this document, the term "or" is used to refer to a nonexclusive or, such that "A or B" includes "A but not B," "B but not A," and "A and B," unless otherwise indicated. In the appended claims, the terms "including" and "in which" are used as the plain-English equivalents of the respective terms "comprising" and "wherein." Also, in the following claims, the terms "including" and "comprising" are open-ended, that is, a system, device, article, or process that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms "first," "second," and "third," etc. are used merely as labels, and are not intended to suggest a numerical order for their objects.

[00115] The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more aspects thereof) may be used in combination with others. Other embodiments may be used, such as by one of ordinary skill in the art upon reviewing the above description. The Abstract is to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. However, the claims may not set forth features disclosed herein because embodiments may include a subset of said features. Further, embodiments may include fewer features than those disclosed in a particular example. Thus, the following claims are hereby incorporated into the Detailed Description, with a claim standing on its own as a separate embodiment. The scope of the embodiments disclosed herein is to be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.