TECHNICAL FIELD

The present invention is directed, in general, to communication systems and, in particular, to an apparatus, method and system configured to reduce interference for user equipment operable in disparate communication systems.

BACKGROUND

Long term evolution ("LTE") of the Third Generation Partnership Project ("3GPP"), also referred to as 3GPP LTE, refers to research and development involving the 3GPP LTE Release 8 and beyond as part of an ongoing effort across the industry aimed at identifying technologies and capabilities that can improve systems such as the universal mobile telecommunication system ("UMTS")- The notation "LTE-A" is generally used in the industry to refer to further advancements in LTE. The goals of this broadly based project include improving communication efficiency, lowering costs, improving services, making use of new spectrum opportunities, and achieving better integration with other open standards.

The evolved universal terrestrial radio access network ("E-UTRAN") in 3GPP includes base stations providing user plane (including packet data convergence protocol/radio link control/media access control/physical ("PDCP/RLC/MAC/PHY") sublayers) and control plane (including radio resource control ("RRC") sublayer) protocol terminations towards wireless communication devices such as cellular telephones. A wireless communication device or terminal is generally known as user equipment (also referred to as "UE"). A base station is an entity of a communication system or network often referred to as a Node B or an NB. Particularly in the E-UTRAN, an "evolved" base station is referred to as an eNodeB or an eNB. For details about the overall architecture of the E-UTRAN, see 3GPP Technical

Specification ("TS") 36.300 v8.7.0 (2008-12), which is incorporated herein by reference. For details of the radio resource control management, see 3GPP TS 25.331 v.9.1.0 (2009-12) and 3GPP TS 36.331 v.9.1.0 (2009-12), which are incorporated herein by reference.

As wireless communication systems such as cellular telephone, satellite, and microwave communication systems become widely deployed and continue to attract a growing number of users, there is a pressing need to accommodate a large and variable number of communication devices that transmit an increasing quantity of data within a fixed spectral allocation and limited transmit power. The increased quantity of data is a consequence of wireless communication devices transmitting video information and surfing the Internet, as well as performing ordinary voice communication. The aforementioned services are provided while accommodating substantially simultaneous operation of a large number of wireless communication devices.

A further continuing development is the introduction of communication systems such as wireless local area networks ("WLANs") (e.g. , WiMax communication systems) that provide alternative communication services for mobile and fixed-point equipment, and that use frequency bands or channels adjacent to those used by traditional cellular communication systems or networks such as 3GPP LTE communication systems (also referred to as LTE communication systems). Coexistence between the cellular communication systems and the WLAN communication systems sometimes introduces problematic interference

therebetween. The interference has been observed between the LTE communication system and the industrial, scientific and medical ("ISM") radio bands used by the WLAN communication systems, especially for communication by a device such as user equipment operable in both communication systems or networks.

The 3 GPP LTE and ISM technologies working on adjacent frequencies have been observed to exhibit several interference types. One interference type is an ISM device blocking an LTE user equipment, and vice versa. Another interference type is spurious emission from an ISM device producing a level of interference to LTE user equipment, and vice versa. It is generally recognized that a filter for a transceiver of the device or user equipment cannot provide sufficient rejection on an adjacent frequency to eliminate interference between two adjacent communication systems. Accordingly, a generic radio frequency ("RF") front-end design is not expected to resolve this interference problem.

One of the more problematic issues is how to manage the coexistence of two disparate communication systems such as a cellular communication system (e.g. , a LTE

communication system) and a WLAN communication system. In view of the growing deployment of communication systems such as cellular communication systems as well as WLAN communication systems operating within the same physical area and the introduction of user equipment that is operable with both communication systems, it would be beneficial to coordinate the communications to reduce or avoid interference between the disparate communication systems. SUMMARY

These and other problems are generally solved or circumvented, and technical advantages are generally achieved, by embodiments of the present invention, which include an apparatus, method and system configured to reduce interference for user equipment operable in disparate communication systems. In one embodiment, the apparatus includes a processor and memory including computer program code configured to, with the processor, cause the apparatus to provide an indication of wireless local area network (WLAN) communications over a WLAN channel during a measurement period, direct signal quality measurements of cellular communications over a cellular channel adjacent the WLAN channel for the measurement period, and provide a relative signal quality measurement report of the signal quality measurements of the cellular communications over the cellular channel corresponding to when the WLAN communications over the WLAN channel are active and not active.

The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter, which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures or processes for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

FIGURES 1 and 2 illustrate system level diagrams of embodiments of communication systems including a base station and wireless communication devices that provide an environment for application of the principles of the present invention;

FIGURES 3 to 5 illustrate system level diagrams of embodiments of communication systems including wireless communication systems that provide an environment for application of the principles of the present invention;

FIGURE 6 illustrates a system level diagram of an embodiment of a communication element of a communication system for application of the principles of the present invention;

FIGURE 7 illustrates a diagram illustrating exemplary operations and functionality within a user equipment and a base station associated with communications with disparate communication systems according to the principles of the present invention;

FIGURE 8 illustrates a flowchart demonstrating an exemplary method of operating a WLAN module of user equipment according to the principles of the present invention;

FIGURE 9 illustrates a flowchart demonstrating an exemplary method of operating a cellular module of user equipment according to the principles of the present invention; and

FIGURE 10 illustrates a diagram illustrating exemplary operations and functionality within a user equipment and a base station associated with communications with disparate communication systems according to the principles of the present invention.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The making and using of the presently preferred embodiments are discussed in detail below. It should be appreciated, however, that the present invention provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed are merely illustrative of specific ways to make and use the invention, and do not limit the scope of the invention. In view of the foregoing, the present invention will be described with respect to exemplary embodiments in a specific context of an apparatus, method and system to enable cellular and WLAN communications for user equipment to coordinate the respective operations to manage interference between the two communication systems. The apparatus, method and system are applicable, without limitation, to any communication system including existing and future cellular technologies including 3GPP technologies (i.e., UMTS, LTE, and its future variants such as 4th generation ("4G") communication systems) and a WLAN operable under IEEE Standard 802.11 (or WiMax operable under IEEE Standard 802.16), which are incorporated herein by reference.

Turning now to FIGURE 1, illustrated is a system level diagram of an embodiment of a communication system including a base station 115 and wireless communication devices (e.g. , user equipment) 135, 140, 145 that provides an environment for application of the principles of the present invention. The base station 115 is coupled to a public switched telephone network (not shown). The base station 115 is configured with a plurality of antennas to transmit and receive signals in a plurality of sectors including a first sector 120, a second sector 125, and a third sector 130, each of which typically spans 120 degrees.

Although FIGURE 1 illustrates one wireless communication device (e.g. , wireless communication device 140) in each sector (e.g. the first sector 120), a sector (e.g. the first sector 120) may generally contain a plurality of wireless communication devices. In an alternative embodiment, a base station 115 may be formed with only one sector (e.g. the first sector 120), and multiple base stations may be constructed to transmit according to cooperative multi-input/multi-output ("C-MIMO") operation, etc.

The sectors (e.g. the first sector 120) are formed by focusing and phasing radiated signals from the base station antennas, and separate antennas may be employed per sector (e.g. the first sector 120). The plurality of sectors 120, 125, 130 increases the number of subscriber stations (e.g. , the wireless communication devices 135, 140, 145) that can simultaneously communicate with the base station 115 without the need to increase the utilized bandwidth by reduction of interference that results from focusing and phasing base station antennas. While the wireless communication devices 135, 140, 145 are part of a primary communication system, the wireless communication devices 135, 140, 145 and other devices such as machines (not shown) may be a part of a secondary communication system to participate in, without limitation, device-to-device and machine-to-machine communications or other communications.

Turning now to FIGURE 2, illustrated is a system level diagram of an embodiment of a communication system including a base station 210 and wireless communication devices (e.g. , user equipment) 260, 270 that provides an environment for application of the principles of the present invention. The communication system includes the base station 210 coupled by communication path or link 220 (e.g. , by a fiber-optic communication path) to a core telecommunications network such as public switched telephone network ("PSTN") 230. The base station 210 is coupled by wireless communication paths or links 240, 250 to the wireless communication devices 260, 270, respectively, that lie within its cellular area 290.

In operation of the communication system illustrated in FIGURE 2, the base station

210 communicates with each wireless communication device 260, 270 through control and data communication resources allocated by the base station 210 over the communication paths 240, 250, respectively. The control and data communication resources may include frequency and time-slot communication resources in frequency division duplex ("FDD") and/or time division duplex ("TDD") communication modes. While the wireless communication devices 260, 270 are part of a primary communication system, the wireless communication devices 260, 270 and other devices such as machines (not shown) may be a part of a secondary communication system to participate in, without limitation, device-to- device and machine-to-machine communications or other communications.

Turning now to FIGURE 3, illustrated is a system level diagram of an embodiment of a communication system including a wireless communication system that provides an environment for the application of the principles of the present invention. The wireless communication system may be configured to provide evolved UMTS terrestrial radio access network ("E-UTRAN") universal mobile telecommunications services. A mobile management entity/system architecture evolution gateway ("MME/SAE GW," one of which is designated 310) provides control functionality for an E-UTRAN node B (designated "eNB," an "evolved node B," also referred to as a "base station," one of which is designated 320) via an S I communication link (ones of which are designated "S I link"). The base stations 320 communicate via X2 communication links (ones of which are designated "X2 link"). The various communication links are typically fiber, microwave, or other high- frequency metallic communication paths such as coaxial links, or combinations thereof.

The base stations 320 communicate with wireless communication devices such as user equipment ("UE," ones of which are designated 330), which is typically a mobile transceiver carried by a user. Thus, communication links (designated "Uu" communication links, ones of which are designated "Uu link") coupling the base stations 320 to the user equipment 330 are air links employing a wireless communication signal such as, for example, an orthogonal frequency division multiplex ("OFDM") signal. While the user equipment 330 are part of a primary communication system, the user equipment 330 and other devices such as machines (not shown) may be a part of a secondary communication system to participate in, without limitation, device-to-device and machine-to-machine communications or other communications.

Turning now to FIGURE 4, illustrated is a system level diagram of an embodiment of a communication system including a wireless communication system that provides an environment for the application of the principles of the present invention. The wireless communication system provides an E-UTRAN architecture including base stations (one of which is designated 410) providing E-UTRAN user plane (packet data convergence protocol/radio link control/media access control/physical) and control plane (radio resource control) protocol terminations towards wireless communication devices such as user equipment 420 and other devices such as machines 425 (e.g. , an appliance, television, meter, etc.). The base stations 410 are interconnected with X2 interfaces or communication links (designated "X2"). The base stations 410 are also connected by S I interfaces or

communication links (designated "SI") to an evolved packet core ("EPC") including a mobile management entity/system architecture evolution gateway ("MME/SAE GW," one of which is designated 430). The SI interface supports a multiple entity relationship between the mobile management entity/system architecture evolution gateway 430 and the base stations 410. For applications supporting inter-public land mobile handover, inter-eNB active mode mobility is supported by the mobile management entity/system architecture evolution gateway 430 relocation via the SI interface.

The base stations 410 may host functions such as radio resource management. For instance, the base stations 410 may perform functions such as internet protocol ("IP") header compression and encryption of user data streams, ciphering of user data streams, radio bearer control, radio admission control, connection mobility control, dynamic allocation of communication resources to user equipment in both the uplink and the downlink, selection of a mobility management entity at the user equipment attachment, routing of user plane data towards the user plane entity, scheduling and transmission of paging messages (originated from the mobility management entity), scheduling and transmission of broadcast information (originated from the mobility management entity or operations and maintenance), and measurement and reporting configuration for mobility and scheduling. The mobile management entity/system architecture evolution gateway 430 may host functions such as distribution of paging messages to the base stations 410, security control, termination of user plane packets for paging reasons, switching of the user plane for support of the user equipment mobility, idle state mobility control, and system architecture evolution bearer control. The user equipment 420 and machines 425 receive an allocation of a group of information blocks from the base stations 410.

Additionally, the ones of the base stations 410 are coupled to a home base station 440 (a device), which is coupled to devices such as user equipment 450 and/or machines (not shown) for a secondary communication system. The base station 410 can allocate secondary communication system resources directly to the user equipment 420 and machines 425, or to the home base station 440 for communications (e.g. , local communications) within the secondary communication system. For a better understanding of home base stations (designated "HeNB"), see 3 GPP TS 32.871 v.9.1.0 (2010-03), which is incorporated herein by reference. While the user equipment 420 and machines 425 are part of a primary communication system, the user equipment 420, machines 425 and home base station 440 (communicating with other user equipment 450 and machines (not shown)) may be a part of a secondary communication system to participate in, without limitation, device-to-device and machine-to-machine communications or other communications.

Turning now to FIGURE 5, illustrated is a system level diagram of an embodiment of a communication system including a wireless communication system that provides an environment for the application of the principles of the present invention. The illustrated embodiment provides a WLAN communication system such as a WiMax communication system typically configured according to IEEE Standard 802.16. The WiMax

communication system includes a core service network ("CSN") including a home access ("HA") server. The core service network provides authentication, authorization, and accounting ("AAA") functions via an AAA server, dynamic host configuration protocol ("DHCP") functions via a DHCP server, billing functions via a billing server, and a policy function ("PF") server. The AAA server validates user credentials, determines functions permissible under a given set of operating conditions and tracks network utilization for billing and other purposes. The DHCP server is used to retrieve network configuration information such as Internet protocol address assignments. The policy function server coordinates various network resources to provide requested services to authorized subscribers, and is responsible for identifying policy rules for a service that a subscriber may intend to use.

The WiMax communication system further includes access service networks ("ASNs") that include ASN gateways (ASN-GWs") and base stations ("BSs") that provide wireless communication with user equipment ("UE"). A home access server communicates with the access service networks over R3 interfaces, and the ASN-GWs communicate with other ASN-GWs over R4 interfaces. The ASN-GWs communicate with base stations over R6 interfaces. The base stations communicate with the user equipment over wireless Rl interfaces.

Turning now to FIGURE 6, illustrated is a system level diagram of an embodiment of a communication element 610 of a communication system for application of the principles of the present invention. The communication element or device 610 may represent, without limitation, a base station, a wireless communication device (e.g. , a subscriber station, terminal, mobile station, user equipment, machine), a network control element, a communication node, or the like. The communication element 610 includes, at least, a processor 620, memory 650 that stores programs and data of a temporary or more permanent nature, an antenna 660, and a radio frequency transceiver 670 coupled to the antenna 660 and the processor 620 for bidirectional wireless communication. The communication element 610 may provide point-to-point and/or point-to-multipoint communication services.

The communication element 610, such as a base station in a cellular network, may be coupled to a communication network element, such as a network control element 680 of a public switched telecommunication network ("PSTN"). The network control element 680 may, in turn, be formed with a processor, memory, and other electronic elements (not shown). The network control element 680 generally provides access to a telecommunication network such as a PSTN. Access may be provided using fiber optic, coaxial, twisted pair, microwave communication, or similar link coupled to an appropriate link-terminating element. A communication element 610 formed as a wireless communication device is generally a self-contained device intended to be carried by an end user.

The processor 620 in the communication element 610, which may be implemented with one or a plurality of processing devices, performs functions associated with its operation including, without limitation, precoding of antenna gain/phase parameters (precoder 621), encoding and decoding (encoder/decoder 623) of individual bits forming a communication message, formatting of information, and overall control (controller 625) of the

communication element, including processes related to management of communication resources (resource manager 628). Exemplary functions related to management of communication resources include, without limitation, hardware installation, traffic management, performance data analysis, tracking of end users and equipment, configuration management, end user administration, management of wireless communication devices, management of tariffs, subscriptions, security, billing and the like. For instance, in accordance with the memory 650, the resource manager 628 is configured to allocate primary and secondary communication resources (e.g. , time and frequency communication resources) for transmission of voice communications and data to/from the communication element 610 and to format messages including the communication resources therefor in a primary and secondary communication system.

The execution of all or portions of particular functions or processes related to management of communication resources may be performed in equipment separate from and/or coupled to the communication element 610, with the results of such functions or processes communicated for execution to the communication element 610. The processor 620 of the communication element 610 may be of any type suitable to the local application environment, and may include one or more of general-purpose computers, special purpose computers, microprocessors, digital signal processors ("DSPs"), field-programmable gate arrays ("FPGAs"), application-specific integrated circuits ("ASICs"), and processors based on a multi-core processor architecture, as non-limiting examples.

The transceiver 670 of the communication element 610 modulates information on to a carrier waveform for transmission by the communication element 610 via the antenna(s) 660 to another communication element. The transceiver 670 demodulates information received via the antenna(s) 660 for further processing by other communication elements. The transceiver 670 is capable of supporting duplex operation for the communication element 610. The memory 650 of the communication element 610, as introduced above, may be one or more memories and of any type suitable to the local application environment, and may be implemented using any suitable volatile or nonvolatile data storage technology such as a semiconductor-based memory device, a magnetic memory device and system, an optical memory device and system, fixed memory, and removable memory. The programs stored in the memory 650 may include program instructions or computer program code that, when executed by an associated processor, enable the communication element 610 to perform tasks as described herein. Of course, the memory 650 may form a data buffer for data transmitted to and from the communication element 610. Exemplary embodiments of the system, subsystems, and modules as described herein may be implemented, at least in part, by computer software executable by processors of, for instance, the wireless communication device and the base station, or by hardware, or by combinations thereof. The systems, subsystems and modules may be embodied in the communication element 610 as illustrated and described herein.

As will become more apparent, when the communication element 610 represents user equipment, the user equipment may be configured to operate in a cellular communication mode (e.g. , a LTE communication mode) and/or a WLAN communication mode. If the user equipment is configured to operate in both the cellular (or LTE) and WLAN communication modes, the user equipment may include an internetworking subsystem 626 including a cellular (or LTE) module that coordinates selected cellular functionality and a WLAN module that coordinates selected WLAN functionality. As a result, the user equipment may reduce interference between cellular communications over a cellular channel and WLAN communications over a WLAN channel. A common time reference for the disparate modes of communication is maintained by a common clock 630. When the communication element represents a base station (e.g. , in accordance with a resource manager 628), the base station may be configured to provide corrective action for the user equipment to reduce the interference between the cellular communications over the cellular channel and the WLAN communications over the WLAN channel in accordance with reporting from the user equipment.

There has been discussion in the 3GPP LTE community of various features of the

3 GPP LTE standard that might be utilized to mitigate coexistence problems between a cellular and WLAN communication system. Messages, procedures and techniques are introduced herein to facilitate coexistence between the cellular and WLAN communication systems to ensure that user equipment transmission and reception behaviors are coordinated with a base station to reduce these problems.

The general problem of interference between a cellular communication system and another communication system is not restricted to WLAN communication systems. Similar interference can also be produced between a cellular communication system and a Bluetooth communication system. Accordingly, the processes and methods described hereinbelow are not restricted to interference with WLAN communication systems.

It has been proposed that a new network signaling value "NS_10" be introduced in 3GPP TS 36.101 v.9.2.0 (2009- 12), which is incorporated herein by reference, to indicate that a user equipment will meet an additional requirement for coexistence with a WLAN communication system in a deployment scenario as part of a cell handover/broadcast message. As proposed, the user equipment will work in a subband upon receipt of a network signal indicating a need to achieve a blocking requirement. Otherwise, the user equipment can work in the entire band.

Several other general solutions to the coexistence problem have been discussed. One solution includes enhanced reporting by a user equipment to make the cellular

communication system aware of a coexistence issue with a WLAN communication system, and a handover/radio link failure ("HO/RLF") mechanism to move a user equipment to a frequency or radio access technology ("RAT") that does not have a coexistence issue with the ISM radio band. When handover ("HO") is not possible, which may be the case if the user equipment is in an area with deployment of only one frequency, or if the user equipment does not have good channel quality in an alternate frequency, or even if the user equipment does not support multiple radio access technologies, allowing time sharing between the cellular and WLAN communication systems in a manner that is coordinated or controlled by, for instance, a base station could be considered. A further solution is to constrain assignment of a given user equipment to selected frequencies of a cellular communication system that avoids coexistence issues with a WLAN communication system.

Another consideration that has been discussed is introducing a mechanism to control the interaction between downlink and uplink communication resource allocations by communication resource schedulers (e.g. , in accordance with a resource manager of a base station) so that a scheduler can predict the frequency location of spurious emissions caused by an uplink signal transmission to reduce user equipment self-interference in a frequency- division duplex ("FDD") system via cooperation between downlink and uplink schedulers. Techniques to reduce possible self-interference in a user equipment with a WLAN communication system have been considered for an uplink scheduler to set lower and upper limits up to a precision of a physical resource block ("PRB") for a physical uplink shared channel ("PUSCH") communication resource allocation.

A mechanism has been discussed for cooperation between a cellular communication system such as a LTE communication system and video and data transmission technologies such as MediaFlo that broadcast one way signals to mobile devices such as user equipment. The user equipment may signal to the cellular communication system that it is currently in a MediaFlo television broadcast receiving mode, as well as identifying time slots in which a cellular uplink transmission could be scheduled without interrupting the MediaFlo broadcast stream. A mechanism has also been discussed to prevent interference with television broadcast reception produced by a cellular uplink transmission. The MobileTV receiver burst timing is signaled from a receiver to the user equipment, which forwards the information to a base station uplink scheduler. The uplink ("UL") scheduler configures the cellular communication system allocation for the user equipment so that interference with mobile television reception is reduced. For exemplary applications related to the cooperation between disparate communication systems, see PCT Application Nos. PCT/EP2009/053839 and PCT/IB2010/001180, which are incorporated herein by reference.

From the perspective of a WLAN communication system causing interference with the cellular communication system, an internetworking subsystem is introduced herein between the WLAN and cellular radio protocol stack to convey information known at the user equipment for the management of a WLAN communication and a cellular

communication in the user equipment. The internetworking subsystem may provide an indication of a WLAN communication after receiving a clear-to-send ("CTS") message, if a request-to-send/clear-to-send ("RTS/CTS") procedure is employed. Then the

internetworking subsystem directs or performs a signal quality measurement such as an intra- band (or -channel) reference signal received quality ("RSRQ") measurement when the user equipment is transmitting a WLAN communication and other signal strength and/or quality measurements when the user equipment is not transmitting a WLAN communication. The RSRQ measurement parameter is defined as a ratio (N) RSRP/RSSI, where N is the number of resource blocks of the cellular carrier or channel received signal strength indicator ("RSSI") measurement bandwidth. The RSSI measurement parameter is the total received wideband power by the user equipment from all sources including co-channel serving and non-serving cells, adjacent channel interference and thermal noise within the measurement bandwidth. A reference signal received power ("RSRP") is defined for a specific cell as a linear average over the power contributions of the communication resource elements that carry cell-specific reference signals within the considered measurement frequency bandwidth. While the RSRP measurement parameter is an indicator of the wanted signal strength, the RSRQ measurement parameter additionally takes the interference level into account due to the inclusion of the RSSI measurement parameter. Of course, other signal quality and strength measurements are well within the broad scope of the present invention.

A problem might arise if there is not enough time between a received CTS message and the start of a WLAN communication to process information about the transmission to coordinate activity with respect to the WLAN and cellular communications. In addition, the RTS/CTS mechanism is not always used prior to a WLAN transmission. To overcome the aforementioned problem, a new indication message is sent between a WLAN module and a cellular module (e.g. , an LTE module) within the internetworking subsystem via a new interface to indicate that there is data in a WLAN buffer to be transmitted (i.e. , a WLAN communication is to be transmitted). Then, the internetworking subsystem initiates RSRQ measurements and continues until another indication is received from the WLAN module to stop the measurements, or until a certain time period has elapsed. This procedure is followed by a message from the WLAN module to the cellular module or otherwise that shows transmission times on a time line, wherein the time is related to a common clock in the user equipment shared by both WLAN and cellular modules. Using the new indication message, the cellular module evaluates the RSRQ measurement samples by marking each sample either as "active" or "not active" based on the indication message received from WLAN module. Thus, the cellular module can construct a relative RSRQ measurement of samples for which WLAN transmission is active and not active. The relative measurement can be considered as the RSSI difference due to increased interference resulting from active WLAN transmission on an adjacent band or channel. The user equipment reports the relative RSRQ measurement parameter to a base station to evaluate and perform corrective actions for the user equipment.

In one corrective action, the base station institutes scheduler restrictions to prevent allocating communication resources at the edge of a cellular channel next to the WLAN band. In another corrective action, the base station hands the user equipment over, for example, to another frequency band or to another base station. In a further corrective action, the user equipment in an idle state can use the RSRQ measurements from different sample occasions to evaluate reselection criteria, possibly to change a base station or communication resources such as frequency or time slots for a cellular communication.

The user equipment can reduce the priority of the channel, frequency, or time slot impacted by WLAN usage by adding a negative offset into a priority received on broadcast information from a base station for that channel, frequency, or time slot for further reselection evaluation. Setting the priority of the impacted communication resource such as a frequency to zero would allow dismissing the particular communication resource for a while in further reselection evaluations.

Alternatively, the user equipment may assume some level and range of WLAN activity, required WLAN transmission power, and some roll-off factor to estimate expected interference on the cellular communication resource, and do a reselection of the

communication resource if the interference is expected to be too high. Also, the user equipment may suggest via the radio resource control layer that a particular carrier frequency of a base station be entered into a "black cell list" from the point of view of the user equipment. If the base station receives similar information from any user equipment in its cell, the base station may enter the particular carrier frequency into a black cell list for all the user equipment in the cell or only user equipment in a certain physical area if the location information of the user equipment is available at the base station. From the perspective of the cellular communication system causing interference to the WLAN communication system, the cellular communication system may indicate that the used band or channel while on the cellular communication system is adjacent to known ISM bands. The indication fields may be conveyed in the radio resource control layer to the user equipment, and the indication can trigger several actions.

A cellular (e.g. , an LTE module) module within the user equipment could request interference measurements from a WLAN module in the user equipment related to communication resources that are used by the WLAN module in the user equipment to sense whether or not a WLAN channel(s) is busy. The WLAN module may respond to the cellular module that there is not a problem accessing the channels, and thus further actions may be relaxed for a period of time. If the WLAN module observes that the channels are quite busy, it may include interference values with timestamps tied to a common clock in the user equipment, and provide this information to the cellular module in the user equipment. The cellular module in the user equipment can then analyze the interference measurement values against its uplink transmission history to form a quantitative or qualitative estimation about the cellular communication impacting operation of the WLAN communication. If the cellular module observes that the cellular communication is causing a level of interference on the WLAN communication, the cellular module could then inform the WLAN module within the user equipment about used uplink/downlink division of communication resources in the cell (such as an allocation of channels, frequencies, or time slots), so that the WLAN module can avoid trying to access the WLAN communication system during the uplink portion of a cellular communication, which is a suitable arrangement in a cellular time-division duplex ("TDD") communication system, particularly if the uplink communication resources are partitioned in time slots.

An alternative would be that the cellular module informs the WLAN module in the beginning of the used uplink/downlink division of communication resources so that uplink time slots associated with a cellular communication may be avoided. In another alternative employable when a WLAN access point is in control of the operator controlling the cellular communication radio, the user equipment may convey information about interference by the cellular communications to the WLAN communications, and the operator may then change parameters of the WLAN access point. The descriptions of the procedures that follow provide exemplary methods of coordinating communications in accordance with user equipment to disparate communication systems that address potential interference associated therewith.

Turning now to FIGURE 7, illustrated is a diagram illustrating exemplary operations and functionality within a user equipment 710 and a base station 790 associated with communications with disparate communication systems according to the principles of the present invention. The user equipment 710 includes a WLAN module 720 that coordinates activities related to WLAN functionality and a cellular module 730 that coordinates activities related to cellular functionality. The user equipment is constructed with a common clock 740 that identifies time both to the WLAN module 720 and the cellular module 730. The common clock 740 provides a common time reference for both the WLAN and cellular communications in the user equipment.

Beginning with steps or modules 750, 755, the WLAN module 720 is synchronized with the cellular module 730 via the common clock 740. A step or module 760 identifies and coordinates measurement parameters such as signal quality measurement parameters (e.g. , RSRQ, RSSI and RSRP measurement parameters) and informs both the WLAN and cellular modules 720, 730 of a measurement period for acquiring the measurement parameters. At some point in time after coordination of the measurement parameters, the user equipment produces data to transmit, such as voice or video data, on a WLAN channel of the WLAN communication system. The WLAN module 720 provides an indication to the cellular module 730 about new/upcoming WLAN transmissions (i.e. , a WLAN communication). The cellular module 730 coordinates signal quality measurements (e.g. , RSRQ measurements) on a cellular channel of the cellular communication system adjacent to the WLAN channel as represented by a step or module 765. These RSRQ measurements are made over the measurement period. A measurement period is indicated in FIGURE 7 with a timeout to receive an indication of the WLAN transmission.

The cellular module 730 then sends an inquiry to the WLAN module 720 related to the indication by the WLAN module 720 about a new/upcoming WLAN transmission. The WLAN module 720 then coordinates the related transmission on the WLAN channel as represented by a step or module 770. The WLAN module 720 provides an indication of timestamps of the WLAN transmissions within a measurement period (or window) to the cellular module 730. In a step or module 780, the cellular module 730 produces a relative RSRQ measurement report that is transmitted over an uplink channel of a cellular communication system to the base station 790 corresponding to when the WLAN transmissions (or communications) are active and not active. Based on the relative RSRQ measurement report, the base station may take corrective action as described above to reduce or avoid interference between the WLAN communication on the WLAN channel and a cellular communication on the cellular channel.

Turning now to FIGURE 8, illustrated is a flowchart demonstrating an exemplary method of operating a WLAN module of user equipment according to the principles of the present invention. The method starts at step or module 810. At a step of module 820, measurement parameters such as a measurement period are identified and coordinated with a cellular module in the user equipment. At a step or module 830, the WLAN module receives acknowledgment of the measurement parameters from the cellular module. The cellular module may propose different parameters to be measured from those identified by the WLAN module. In a decisional step or module 840, the WLAN module repeatedly checks for new data in a buffer new/upcoming WLAN transmissions. When new data is found, in a step or module 850 an indication about new/upcoming WLAN transmissions is sent to the cellular module. In a decisional a step or module 860, the WLAN module repeatedly checks for an expiration of the measurement period or if the data buffer is empty. In a step or module 870, when the measurement period expires or the data buffer is empty, an indication of past WLAN transmissions within the measurement period (or window) and their timestamps is sent to the cellular module. The method ends at a step or module 880.

Turning now to FIGURE 9, illustrated is a flowchart demonstrating an exemplary method of operating a cellular module of user equipment according to the principles of the present invention. The method starts at a step or module 910. In a step or module 920, the cellular module receives proposed measurement parameters such as a measurement period from a WLAN module. In a step or module 930, coordination of the measurement parameters with the WLAN module of the user equipment is performed. In a step or module 940, the cellular module receives an indication about new/upcoming WLAN transmissions from the WLAN module. In a step or module 950, signal quality measurements (e.g. , RSRQ measurements) are performed on a cellular channel adjacent a WLAN channel for a WLAN transmission (or communication). In a step or module 960, the cellular module accumulates past WLAN transmissions within a measurement period with their timestamps. In a step or module 970, relative RSRQ measurements are generated from RSRQ samples with identification of whether WLAN transmissions occurred (active) or not (not active). In a step or module 980, the cellular module sends a relative RSRQ measurement report to a base station. The method ends at a step or module 990.

Turning now to FIGURE 10, illustrated is a diagram illustrating exemplary operations and functionality within a user equipment 1010 and a base station 1090 associated with communications with disparate communication systems according to the principles of the present invention. The user equipment 1010 includes a WLAN module 1020 that coordinates activities related to WLAN functionality and a cellular module 1030 that coordinates activities related to cellular functionality. The user equipment 1010 is constructed with a common clock 1040 that identifies time both to the WLAN module 1020 and the cellular module 1030. The common clock 1040 provides a common time reference for both the WLAN and cellular communications in the user equipment.

Beginning with steps or modules 1050, 1055, the WLAN module 1020 is synchronized with the cellular module 1030 via the common clock 1040. The base station 1090 transmits in a downlink communication resource an indication of an adjacent WLAN band or channel to the cellular module 1030, which makes an inquiry to the WLAN module 1020 for information about WLAN activity and interference. The WLAN module 1020 responds with an indication of WLAN activity. In a step or module 1060, the cellular module 1030 keeps a history of information of the uplink transmissions including timestamps and power levels (i. e. , when transmissions occurred (active) or not (not active)). In a step or module 1065, the WLAN module 1020 directs or obtains interference measurements associated with WLAN communications or activity over the WLAN channel from cellular communications over an adjacent cellular channel during measurement periods. The WLAN module 1020 provides the interference measurements with timestamps to the cellular module 1030. In a step or module 1070, the cellular module 1030 provides quantitatively or qualitatively an estimate of an impact on a WLAN band or channel using received interference measurements and its own history information. The cellular module 1030 then provides a cellular downlink/uplink division of communication resources (such as an allocation of channels, frequencies, or time slots) to the WLAN module 1020 for the benefit of employing other communication resources for the WLAN communications. Alternatively, the cellular module 1030 transmits a suggestion to change channels at an access point ("AP") to the WLAN module 1020. The cellular module 1030 then transmits on an uplink to the base station 1090 an indication of interference caused on the WLAN communication including WLAN configuration information. If base station 1090 determines that interference exists between the cellular communication system and the WLAN

communication system, the base station transmits a suggestion to change channels to a WLAN access point 1080. In accordance with the foregoing, the WLAN module 1020 may select another communication resource (e.g. , a WLAN channel) for the WLAN

communications to reduce interference with the cellular communications over the adjacent cellular channel.

Thus, apparatus, methods and systems have been introduced to alleviate interference in a user equipment between a cellular communication system and another wireless communication system such as a WLAN communication system. A WLAN module indicates when a WLAN communication occurs and, in response, the cellular module coordinates RSRQ measurements until a timer expires or the WLAN module signals the cellular module to stop. The cellular module can obtain signal quality or strength (such as a RSSI measurement parameter) from relative RSRQ measurements. The cellular module provides relative signal strength measurements to a base station for evaluation and corrective action. One corrective action is to make scheduler restrictions for uplink or downlink communication resources. Another corrective action is to initiate a handover for the user equipment to another base station or another frequency band or channel. The user equipment evaluates the measurements and may alter reselection criteria in anticipation of a handover. The user equipment may suggest a communication resource such as a channel, frequency, or a time slot to the base station that should be added to a black list of frequencies. If base station receives a number of such black-list suggestions, it may selectively add certain communication resources to its black list.

The cellular module may request the WLAN module to make signal strength measurements, from which the cellular module may judge the impact on a WLAN communication. The cellular module may inform the WLAN module which communication resources are suitable for the WLAN communication. Another alternative may be employed in the case when the WLAN access point is in control of the operator controlling the cellular communications radio. The user equipment may convey information about caused interference from the cellular module to the WLAN module, and the operator controlling the cellular communications radio may then change parameters of the WLAN access point.

Thus, an apparatus, method and system are introduced herein for reducing interference for user equipment operable in disparate communication systems. In one embodiment, an apparatus (e.g. , embodied in a user equipment) includes a processor and memory including computer program code. The memory and the computer program code are configured, with the processor, to cause the apparatus to provide an indication (e.g. , with timestamps) of WLAN communications over a WLAN channel during a measurement period, direct or obtain signal quality measurements (e.g. , a RSRQ measurement, a RSSI

measurement, a RSRP measurement) of cellular communications over a cellular channel adjacent the WLAN channel for the measurement period, and provide a relative signal quality measurement report of the signal quality measurements of the cellular communications over the cellular channel corresponding to when the WLAN communications over the WLAN channel are active and not active. Additionally, the memory and the computer program code are further configured, with the processor, to cause the apparatus to employ other

communication resources or select another cellular channel for the cellular communications to reduce interference with the WLAN communications. The memory and the computer program code are further configured, with the processor, to cause the apparatus to synchronize the WLAN and cellular communications with a common time reference. In another embodiment, an apparatus (e.g. , embodied in a user equipment) includes a processor and memory including computer program code. The memory and the computer program code are configured, with the processor, to cause the apparatus to provide an indication of cellular communications over a cellular channel during a measurement period, provide interference measurements (with timestamps) associated with the WLAN communications over the WLAN channel adjacent the cellular channel during the measurement period, and form an estimate of interference on the WLAN communications over the WLAN channel from the cellular communications over the cellular channel as a function of the interference measurements and corresponding to when the cellular communications over the cellular channel are active and not active. Additionally, the memory and the computer program code are further configured, with the processor, to cause the apparatus to receive an indication of the WLAN channel for the WLAN communications. The memory and the computer program code are further configured, with the processor, to cause the apparatus to employ other communication resources or select another WLAN channel for the WLAN communications to reduce interference with the cellular

communications. The memory and the computer program code are further configured, with the processor, to cause the apparatus to synchronize the WLAN and cellular communications with a common time reference.

In another embodiment, an apparatus (e.g. , embodied in a base station) includes a processor and memory including computer program code. The memory and the computer program code are configured, with the processor, to cause the apparatus to receive a relative signal quality measurement report from user equipment of signal quality measurements (e.g. , a RSRQ measurement, a RSSI measurement, a RSRP measurement) of cellular

communications over a cellular channel adjacent a WLAN channel for WLAN

communications corresponding to when the WLAN communications over the WLAN channel are active and not active, and provide corrective action for the user equipment to reduce interference between the cellular communications over the cellular channel and the WLAN communications over the WLAN channel. Additionally, the memory and the computer program code are further configured, with the processor, to cause the apparatus to receive the relative signal quality measurement report from a plurality of user equipment and provide the corrective action for the plurality of user equipment. As mentioned above, the corrective action may include scheduler restrictions for one of the cellular communications over the cellular channel and the WLAN communications over the WLAN channel. The corrective action may include selecting communication resources for one of the cellular communications over the cellular channel and the WLAN communications over the WLAN channel. The corrective action may include a handover of the user equipment to another base station, or altering a priority of one of the cellular communications over the cellular channel and the WLAN communications over the WLAN channel.

Program or code segments making up the various embodiments of the present invention may be stored in a computer readable medium (e.g. , non-transitory computer readable medium) or transmitted by a computer data signal embodied in a carrier wave, or a signal modulated by a carrier, over a transmission medium. For instance, a computer program product including a program code stored in a computer readable medium may form various embodiments of the present invention. The "computer readable medium" may include any medium that can store or transfer information. Examples of the computer readable medium include an electronic circuit, a semiconductor memory device, a read only memory ("ROM"), a flash memory, an erasable ROM ("EROM"), a floppy diskette, a compact disk ("CD")-ROM, an optical disk, a hard disk, a fiber optic medium, a radio frequency ("RF") link, and the like. The computer data signal may include any signal that can propagate over a transmission medium such as electronic communication network communication channels, optical fibers, air, electromagnetic links, RF links, and the like. The code segments may be downloaded via computer networks such as the Internet, Intranet, and the like.

As described above, the exemplary embodiment provides both a method and corresponding apparatus consisting of various modules providing functionality for performing the steps of the method. The modules may be implemented as hardware (embodied in one or more chips including an integrated circuit such as an application specific integrated circuit), or may be implemented as software or firmware for execution by a computer processor. In particular, in the case of firmware or software, the exemplary embodiment can be provided as a computer program product including a computer readable storage structure embodying computer program code (i.e., software or firmware) thereon for execution by the computer processor.

Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. For example, many of the features and functions discussed above can be implemented in software, hardware, or firmware, or a combination thereof. Also, many of the features, functions and steps of operating the same may be reordered, omitted, added, etc. , and still fall within the broad scope of the present invention.

Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed, that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.