WO2013123638A1

WO2013123638A1 - Methods and apparatus for interference management

Info

Publication number: WO2013123638A1
Application number: PCT/CN2012/071361
Authority: WO
Inventors: Haiming Wang; Tao Chen; Yuan QI; Tao Peng
Original assignee: Renesas Mobile Corporation
Priority date: 2012-02-20
Filing date: 2012-02-20
Publication date: 2013-08-29

Abstract

Methods and apparatus for managing inter-operator interference. A device experiencing interference conducts device to device communication with another device, associated with another operator, and receives from the other device information relating to inter-operator interference. The device experiencing interference performs analysis using the information received from the other device and determines if it is experiencing strong inter-operator interference. The device reports strong inter-operator interference to a base station and a base station receiving such a report delivers measurement requirements to its user equipments. User equipments conduct measurements according to measurement requirements, and the measurements are analyzed to identify user equipments that are victims of strong inter-operator interference. The base station performs resource allocation to reduce inter-operator interference.

Description

METHODS AND APPARATUS FOR INTERFERENCE MANAGEMENT

TECHNICAL FIELD:

[0001] The exemplary and non-limiting embodiments of this invention relate generally to wireless communication systems, methods, devices and computer programs, and more specifically relate to communication between devices belonging to different networks and use of the information communicated between devices to reduce interference between networks.

BACKGROUND:

[0002] The following abbreviations that may be found in the specification and/or the drawing figures are defined as follows:

3 GPP third generation partnership project

eNB node B/base station in an E-UTRAN system

E-UTRAN evolved UTRAN (LTE)

LTE long term evolution (E-UTRAN)

LTE-A long term evolution-advanced (of E-UTRAN)

MAC medium access control

PCC primary component carrier (also termed PCell)

PDCCH physical downlink control channel

PUCCH physical uplink control channel

PUSCH physical uplink shared channel

RAT radio access technology

RF radio frequency

RRC radio resource control

[0003] As wireless communication devices continue to proliferate, the likelihood increases that elements from different operators will be located in the same geographic area and will interfere with one another. Devices belonging to different operators may use different resources, such as different frequency bands, but the resources used by the different operators maybe close enough that elements, such as user devices, frequently referred to as user equipments (UEs) and base stations, such as eNBs, will interfere with one another. Because the interfering and interfered elements belong to different networks, it will often be difficult in such a case for an interfered element to obtain information about the nature of the interference, and it will also be difficult for an interfered UE to communicate with an interfering base station to alleviate the interference, if the interfering base station belongs to another operator.

SUMMARY OF THE INVENTION;

[0004] In an embodiment of the invention, an apparatus for use in a user equipment comprises at least one processor and at least one memory storing computer program code. The at least one memory and the computer program code are arranged to, with the at least one processor, cause the apparatus to perform at least engaging in device to device communications with another user equipment, wherein the other user equipment is operating in a network of an operator other than the operator of a network in which the user equipment is operating, determining, based on the information, if the user equipment is a victim of strong inter-operator interference, and, if the user equipment is a victim of strong inter-operator interference, reporting its status as a victim to a base station.

[0005] In another embodiment of the invention, an apparatus for use in a user equipment comprises at least one processor and at least one memory storing computer program code. The at least one memory and the computer program code are arranged to, with the at least one processor, cause the apparatus to perform at least receiving measurement requirements from a base station and causing the user equipment to perform measurements relating to inter-operator interference on an interfering band of a network in which the user equipment is not operating, wherein the interfering band is one identified based on device to device communications.

[0006] In another embodiment of the invention, an apparatus for use in a base station comprises at least one processor and at least one memory storing computer program code. The at least one memory and the computer program code are arranged to, with the at least one processor, cause the apparatus to perform at least receiving information from a user equipment identifying the user equipment as a victim of strong inter-operator interference, wherein the status of the user equipment is based at least in part on device to device communication carried out with a user equipment of an operator of a network in which the base station is not operating, performing control functions to cause the transmission of measurement requirements to at least one USER EQUIPMENT of the base station, processing measurement information received by the base station from the at least one user equipment to identify user equipments of the base station that are victims of strong inter-operator interference, and allocating resources so as to reduce inter-operator interference to the at least one user equipment.

[0007] In another embodiment of the invention, a method performed in a user equipment comprises engaging in device to device communications with another user equipment, wherein the other user equipment is operating in a network of an operator other than the operator of a network in which the user equipment is operating, determining, based on the information, if the user equipment is a victim of strong inter-operator interference, and, if the user equipment is a victim of strong inter-operator interference, reporting its status as a victim to a base station.

[0008] In another embodiment of the invention, a method performed by a user equipment comprises receiving measurement requirements from a base station and performing measurements relating to inter-operator interference on an interfering band of a network in which the user equipment is not operating, wherein the interfering band is one identified based on device to device communications.

[0009] In another embodiment of the invention, a method performed by a base station comprises receiving information from a user equipment identifying the user equipment as a victim of strong inter-operator interference, wherein the status of the user equipment is based at least in part on device to device communication carried out with a user equipment of an operator of a network in which the base station is not operating, performing control functions to cause the transmission of measurement requirements to at least one USER EQUIPMENT of the base station, processing measurement information received by the base station from the at least one user equipment to identify user equipments of the base station that are victims of strong inter-operator interference, and allocating resources so as to reduce inter-operator interference to the at least one user equipment.

[0010] In another embodiment of the invention, a computer readable medium for use in a user equipment, stores a program of instructions, execution of which by a processor arranges an apparatus of the user equipment to perform at least engaging in device to device communications with another user equipment, wherein the other user equipment is operating in a network of an operator other than the operator of a network in which the user equipment is operating, determining, based on the information, if the user equipment is a victim of strong inter-operator interference, and, if the user equipment is a victim of strong inter-operator interference, reporting its status as a victim to a base station.

[0011] In another embodiment of the invention, a computer readable medium for use in a user equipment stores a program of instructions, execution of which by a processor arranges an apparatus of the user equipment to perform at least receiving measurement requirements from a base station and causing the user equipment to perform measurements relating to inter- operator interference on an interfering band of a network to which the user equipment is not operating, wherein the interfering band is one identified based on device to device communications.

[0012] In another embodiment of the invention, a computer readable medium for use in a base station stores a program of instructions, execution of which by a processor arranges an apparatus of the base station to perform at least receiving information from a user equipment identifying the user equipment as a victim of strong inter-operator interference, wherein the status of the user equipment is based at least in part on device to device communication carried out with a user equipment of an operator of a network in which the base station is not operating, performing control functions to cause the transmission of measurement requirements to at least one USER EQUIPMENT of the base station, processing measurement information received by the base station from the at least one user equipment to identify user equipments of the base station that are victims of strong inter-operator interference, and allocating resources so as to reduce inter-operator interference to the at least one user equipment.

[0013] These and other embodiments of the invention are described below with particularity.

BRIEF DESCRIPTION OF THE DRAWINGS:

[0014] Fig. 1 illustrates a deployment of network cells according to an embodiment of the present invention;

[0015] Fig. 2 illustrates a deployment of network resources illustrating conditions leading to inter-operator interference;

[0016] Fig. 3 illustrates adjacent frequency bands whose interference can be detected and reduced using embodiments of the present invention;

[0017] Fig. 4 illustrates a deployment of network resources including device to device communication according to an embodiment of the present invention;

[0018] Figs. 5 A and 5B illustrate scenarios for device to device communication according to embodiments of the present invention;

[0019] Fig. 6 illustrates a process according to an embodiment of the present invention;

[0020] Fig. 7 illustrates periodic reporting of measurement results according to an embodiment of the present invention;

[0021] Fig. 8 illustrates event triggered reporting of measurement results according to an embodiment of the present invention;

[0022] Fig. 9 illustrates resource reallocation according to an embodiment of the present invention;

[0023] Fig. 10 illustrates a process according to an embodiment of the present invention;

[0024] Fig. 11 illustrates signaling between and operations performed by devices according to one or more embodiments of the present invention;

[0025] Fig. 12 illustrates a user equipment according to an embodiment of the present invention; and

[0026] Fig. 13 illustrates a base station according to an embodiment of the present invention.

DETAILED DESCRIPTION:

[0027] Embodiments of the present invention recognize that many different network deployments maybe implemented, with larger or smaller coverage areas depending on the specific types of base stations being used. A first network, for example, may deploy a variety of different base stations, and a second network may also deploy a variety of base stations. Each base station creates its own coverage area, and coverage areas created by base stations of the first network may overlap, or lie completely within, coverage areas created by base stations of the second network, and vice versa. [0028] Fig. 1 illustrates a combined deployment 100 of network cells 102A- 102E, with the cells 102A-102C being served by base stations 104A-104C operated by a first operator A, with the cells 102D and 102E being served by base stations 104D and 104E, operated by a second operator B, UEs 110A-110O operate in the various cells 102A-102E. Embodiments of the present invention recognize that it is a relatively simple matter to configure UEs to engage in direct communications with one another. Such communications may be referred to as device to device (D2D) communications. D2D communications permits devices to exchange directly, without routing the information through their serving base station. In the present example, the UEs 1 IOC and 11 OD, 11 OH and 1101, and 110M and 11 ON, are shown as being engaged in device to device communication.

[0029] Embodiments of the present invention recognize that because wireless networks must typically serve substantial demands imposed by large numbers of users, the resources allocated to different operators are often immediately adjacent to one another. For example, two different base stations operated by two different operators may operate in geographic areas in which the coverage of the two base stations overlaps. The base stations may operate using different frequency bands, but the frequency bands may be immediately adjacent. A frequency band used by an interfering base station may be close enough to a band used by an interfered user equipment (UE) that the interfering base station imposes substantial interference between the interfered UE and its own serving base station. Such interference is particularly likely to occur when a UE is at its own cell edge. Because cell coverage is not coordinated between different networks, the cell edge of an interfered UE may be well within the coverage area of an interfering base station. Therefore, the interfered UE may receive a lower signal power from its own base station, while being exposed to a higher signal power from the interfering base station.

[0030] Fig. 2 illustrates an interference scenario 200, in which a cell 202 is served by a base station 204, with the base station 204 being operated by a first operator, and a cell 206 is operated by a base station 208, with the base station 206 being operated by a second operator. The base station 204 is serving a UE 210, and the UE 210 is experiencing interference from the base station 208. In the illustrated scenario 200, the base station 204 and the base station 208 use adjacent frequency bands, and the UE 210 is at the cell edge of the base 204, close to the base station 208. The downlink channel of the base station 208 is adjacent to the downlink channel of the base station 204 used by the UE 210, and in the scenario 200 shown, the downlink signal received by the UE 210 suffers interference from leakage of the downlink signal of the base station 208. The particular extent of this interference can be determined by the adjacent channel leakage power ratio (ACLR) and its own adjacent channel selectivity (ACS). Fig. 3 illustrates the adjacent frequency bands 302 and 304, including a downlink component 306 used by the UE 210, and the downlink component 308 used by the base station 208. The received power of the UE 210 is related to the transmitted signal power of the base stations 204 and 208, the pathloss from the base station 204 to the UE 210, the ACLR of the base station 208 and the UE 210's own ACS. If the transmitted signal power of the base station 204 is the same as that of the base station 210, and the pathloss from the base station 204 to the UE 210 is greater than the sum of the pathloss from the base station 208 to the UE 210 and the ACIR, the interference suffered by the UE 210 will be strong. In particular, interference will be very high if the base station 208 is serving a micro cell while the base station 204 is serving a macro cell. The reason for this is that in order to be within the coverage of a micro cell, the UE 210 must be relatively close to the base station, while (in the scenario shown) the UE 210 is at the cell edge of the cell 202, meaning that it is a substantial distance from the base station 204, because a macro cell typically encompasses an area that may be on the order of kilometers from its base station.

[0031] Embodiments of the present invention recognize that devices operating in one operator's network typically are not able to take measurements from elements of other operators' networks. The UE 210 will therefore be unable to receive information from the base station 204 about the base station's downlink transmissions. The UE 210 and the base station 204 will therefore be unable to carry out effective interference coordination.

[0032J Embodiments of the present invention recognize that many possibilities exist for direct communication between UEs, and that such communication need not use the same resources that are used for communication between UEs and their serving base stations. Embodiments of the present invention further recognize that direct device to device (D2D) communication carried out to gather information of the type needed for interference coordination will not require communication rates or reliability on the order of that needed to provide acceptable service to users. The information exchanged between devices for interference coordination typically need be performed only relatively infrequently and can therefore be performed using resources that need not meet rigorous service constraints.

[0033] Fig. 4 therefore illustrates the scenario 200, with the addition of a UE 212 being served by the base station 208. The UE 210 and the UE 212 can communicate directly with one another, suitably through D2D communication in a white space band. A white space band is a frequency band that lies within a range of frequency bands available to users without a need for licensing. The UE 210 and the UE 212 may use this D2D communication to exchange information related to inter-operator interference. The information thus exchanged helps the UEs to analyze inter-operator interference. A UE may thus be assisted in identifying another UE's operator, to obtain information identifying the frequencies or frequency bands being used by the operator and the received power of another UE, and similar information. The content of the information exchanged may, for example, include operator identity (ID) operating band information including bandwidth and center frequency, and received power, such as reference signal received power (RSRP) in evolved universal terrestrial radio access (E-UTRA).

[0034] For the exchange of information, the UEs may use an appropriate predetermined format. One exemplary format is defined below, with information being described in terms of three elements.

[0035]

[0036] B_W2, fc2 denotes bandwidth and center frequency of an interfering band of network 2. "DUE1" and "DUE2" indicate a D2D UEs, meaning that the information is received from a UE through direct communication. The references to "DUEs" and "D2D" UEs distinguish from references to "CUEs" and "cellular" UEs below, from which the information being discussed is received through network communication. For example, information may be reported by one D2D UE to another D2D UE, and information may be reported by a cellular UE to its serving base station [0037] When UEs exchange interference information using D2D, they may adopt any of a number of interaction modes. For example, the UE 210 may send to the UE 212 a request message comprising the information format to be used and the needed information elements, and the UE 212 may return information relevant to inter-operator interference in accordance with the specified requirements. Alternatively, after a D2D link is opened, the UE 212 may send predetermined information to the UE 210 in a specified format, such as the format defined above, with the format and nature of the information being defined in one or more protocols.

[0038] Fig. 5A thus illustrates a signaling diagram 500 according to an embodiment of the present invention. The signaling diagram 500 illustrates first and second UEs 502 and 504, belonging to first and second networks. The first UE 502 sends a request signal 506 to the second UE 504, and the second UE 504 returns an interference information signal 508 to the second UE 504.

[0039] Fig. 5B illustrates a signaling diagram 550, according to an alternative embodiment of the present invention. The first and second UEs 502 and 504 are shown, but in the scenario illustrated by the diagram 550, no request signal is sent. Instead, the second UE 504 simply sends predefined information 552 once it detects that D2D communications have been initiated. For simplicity information is shown as being illustrated as being requested by the UE 502 and delivered by the UE 504, but it will be recognized that either or both of the UEs 502 and 504 may request, or may automatically deliver, information.

[0040] Once inter-operator interference information has been exchanged, or has been delivered from one UE to another, either UE, or both UEs, may evaluate the information to determine if strong inter-operator interference information exists. For simplicity, it is convenient to discuss the analysis of information in terms of the UE 502, with the understanding that any UE involved in a D2D exchange of information related to inter-operator interference may perform the operations of analysis and reporting discussed below.

[0041] After the UE 502 receives inter-operator interference information from the UE 504, it performs an evaluation to determine if strong inter-operator interference exists, and then reports such interference to a base station. Fig. 6 illustrates a process 600 of analysis and reporting according to an embodiment of the present invention. At step 602, a UE performing the analysis, suitably referred to as UEl extracts operator identification and adjacent band information from the received information. At step 604, UEl determines whether a UE from which the information was received, suitably referred to as UE2, has cellular communications with a base station of another operator. If not, the process proceeds to step 606 and the received information is ignored. If UE2 does operate with a base station of another operator, the process proceeds to step 608, and UEl determines whether UE2 is operating in an adjacent frequency band. If not, the process proceeds to step 606 and the received information is ignored. If UE2 is operating in an adjacent frequency band, the process proceeds to step 610.

[0042] At step 610, UEl compares the power that it is receiving with its own received power. The comparison may be performed through the application of a decision rule. The decision rule may comprise the comparing of the received signal power of UEl and

UE2. The comparison may take the form of the equation

where PRX_DUEI_NI and PRX_DUE2_N2 denote the received signal power of the UEl and the UE2. PRX_DUE2_NI denotes the interference suffered by the UE which is caused by adjacent channel leakage power and ACS of the receiver.

[0043] The UEl compares its received power with inter-operator interference as the ratio shown above. If the ratio is greater than a predetermined threshold, the UEl determines that it is encountering strong interference from the other operator's base station, that is, from the base station serving the UE2. The threshold denotes the inter-operator interference that can be tolerated by the UEl and other UEs associated with the same operator. The threshold value may be determined according to any suitable criteria, such as network performance as measured by throughput loss. The value of the threshold can be broadcast from the UEl 's base station, predefined in radio technology protocols, or determined in any other suitable way.

[0044] If the UEl has identified strong inter-operator interference, the process proceeds to step 614 and the interference information is reported to the UEl 's serving base station. The reporting may be performed according to a predetermined protocol defining the information to be delivered, which may comprise UE's operator ID, an operating band which is denoted by interfering bandwidth and center frequency, the received power of the UEl, inter-operator interference, and other relevant information. Such information could be transmitted in the format shown below, where PRX_DUEI_„NI denotes the received power of D2D UE1 measured in its own band, and PRXJJUE-JK the received power of D2D UE2 measured in interfering band. However, any suitable format may be used.

[0045] Upon receiving inter-operator interference information reported by UEs such as the UE1, a base station determines whether strong inter-interference information is present in an adjacent band, requiring further measurement. The base station extracts interfering band information such as network ID, bandwidth and center frequency of the interfering band, to classify the origin of inter-operator interference. A decision can be made for different interfering bands depending on several metrics: UE reporting frequency, the number of UEs reporting the same strong interference, the ratio of received power to interference, and similar information. In one embodiment, the base station maintains a list to count these metrics. To establish the decision rule, a base station might also weigh the expense of measurement at each UE under its control.

[0046] One exemplary format that may be used to organize inter-operator interference information is as follows:

[0047] After a base station has determined that strong inter-operator interference is present in an adjacent band, it sends a measurement requirement to its connected UEs. In order to identify victim UEs, the measurement information may comprise identification of the interfering band which should be measured, measurement items such as received power, measurement period, valid time for measurement period, reporting mode of measurement results, and other suitable parameters.

[0048] The interfering band which should be measured is the operating band of another operator reported from a D2D UE. Measurement items identify the parameters and conditions to be measured by a UE, and the measurements of these items are used by the base station to identify victim UEs effectively. For example, received power might by defined as a measurement item, with the identification of measurement items being defined in protocols or sent by BS.

[0049] To ensure that measurement results are reliable, BS could require UEs to measure such interfering band periodically. Thus a measurement period may be set. In one or more embodiments of the invention, measurements and adjustments may be made in an initial stage of network deployment so that it is not necessary for cellular UEs to keep measurement perpetually. In such a case, an active time for such a measurement period may also be configured. Such an active time might be defined in terms of total time for measurement or the number of measurements to be made. The active time for the measurement period may indicate the time that the inter-operator interfering band measurement is to be terminated.

[0050] A reporting mode may indicate possible ways that cellular UEs reports measurement results to the base stations. In one or more embodiments of the invention, UEs report measurement results in two ways: a periodic mode in which a cellular UE reports measurement results to a base station periodically according to a predefined reporting period, and an event-trigger mode in which cellular UEs report measurement results to a base station upon the occurrence of a triggering event,

[0051] In periodic mode, a reporting period may be defined in measurement information. The reporting period may be configured to be the same as the measurement period or may be set to a different value.

[0052] In event-trigger mode, the triggering event may be defined in protocols or broadcast by a base station. An example of a triggering event might be that the received power of a cellular UE measured in the interfering band is larger than a threshold. If this condition is present, a cellular UE begins start to report measurement results to its base station. The threshold might represent the maximum inter-operator interference that can be tolerated by cellular UEs attached to the base station, so that cellular UEs that are more likely to be suffering interference would be the ones reporting. Thus the threshold of the event may be sent to cellular UEs.

[0053] The following is an example of a measurement information format that may be used for periodic mode:

[0054] The following is an example of a measurement format that may be used for event-trigger mode:

[0055] Such measurement information may be sent through a broadcast channel or a dedicated channel. Receiving the measurement requirement from a cellular base station, the cellular UEs will measure the interfering band and report measurement results to the base station.

[0056] For interfering band measurement, cellular UEs connected to the base station receive measurement requirement which contains measurement items, interfering band, information related to report mode, and etc. It extracts interfering band and measurement items, and adds them into its measurement list.

[0057] For example, a cellular UE may obtain ( {B_w,f_c) , received power) as an interfering band and measurement item. (B_w,f_c) denotes an interfering band of another operator. The cellular TJE then switches its frequency to f_c and measures received power.

[0058] In order to perform measurement results reporting, then after a UE obtains measurement results such as received power in the interfering band, it organizes information for reporting information to help the base station identify victim UEs.

[0059] The measurement results transmitted by a UE may typically coincide with measurement items sent by the base station in a downlink or defined in protocols.

Measurement results describing conditions on the UE's own band may also be included, to allow the base station to identify victim UEs. For example, the received power for an interfering band and a victim band could be involved in the measurement results, but it need not be limited to only those bands. If more than one band is to be measured, measurement results may be combined with information related to the interfering band. An example of a format in which such measurements may be organized is as follows:

[0060] A cellular UE may determine the circumstances under which it reports information based on the specifications given in the reporting requirement specified by the base station or in protocols. If periodic reporting is required, that is, if the reporting mode is periodic mode, the UE sends its measurement results to the base station according the reporting schedule. Fig. 7 illustrates a diagram 700 showing reporting in periodic mode, with reporting events 702, 704, and 706 conducted over reporting intervals 708 and 710, and an overall active measurement period 712. A reporting event occurs at each interval, so that a base station receives reports at predetermined times.

[0061] In periodic mode, measurement results may be sent periodically from all of the UEs of the base station. The base station can thus obtain a general view of the interference conditions, assisting the base station in identifying victim UEs, but at a cost of reporting overhead.

[0062] Fig. 8 illustrates a diagram 800 showing reporting in event trigger mode, with report times 802, 804, 806, 808, and 810, separated by reporting intervals 812, 814, 816, and 818, and an overall active measurement period 820. No reports are actually made at the reporting times because no triggering event has occurred. Once a triggering event 822 occurs, reports are made at the reporting times 808 and 810.

[0063] In the event trigger mode, measurement results are not reported unless a triggering event occurs. In this case, the base station may not receive complete information, but saves reporting overhead.

[0064] Receiving measurement results from UEs allows a base station to identify victim UEs suffering strong inter-operator interference and to implement interference avoidance through resource allocation.

[0065] For all UEs which report measurement results, the base station may organize the information to distinguish victim UEs from UEs which are suffering interference. The information may comprise network ID, interfering band, measurement results, UE ID, and other relevant information. [0066] A list might take the following format:

[0067] For each reporting UE, the base station may determine whether the UE is suffering strong interference from the inter-operator interfering band, and records decisions in the last column in the table above. The number of reporting intervals from a UE can be counted by examining table information and recorded by the base station. In periodic mode, at the end of each period, UEs send measurement results to the base station and the number of reports equals the number of reporting periods.

[0068] In event trigger mode, this item records the number of occurrences of the defined triggering event. The number of reporting times can be introduced in decision rules.

[0069] The base station identifies victim cellular UEs depending on measurement results as evaluated using decision rules. For example, the BS receives received power from cellular UEs in the inter-operator interfering band. If the ratio of the received power of one UE in its own band to that in an interfering band is larger than a certain threshold, the BS may determine that the UE suffers strong inter-operator interference as shown in the following inequality:

[0070]

[0071] , where denotes the received power of UEI measured in its own band

and the received power measured in interfering band. It should be noted that

the ACIR in the computation presented here, performed for cellular UEs, may be different from the ACIR in the computation presented above for D2D UEs, because the ACS of the receivers need not be the same.

[0072] If the UE reports a large received power in an interfering band on several occasions, it will reveal the severity of interference being encountered by the UE. After the base station identifies victim cellular UEs, it may, for example, rearrange information related to severity of interference suffered by victim cellular UEs, in order to establish priorities, for example, by arranging the UEs in a rank ordering based on severity of interference. The following is an example of such a rank ordering:

[0073] Once a base station has received information identifying victim cellular UEs and any available details of the interference suffered by the victim UEs, it may then take steps to avoid interference through resource allocation. For example, victim UEs may be assigned frequency resources that are away from an interfering band. Such assignment may be accomplished through dynamic resource allocation. Alternatively or in addition, a base station may schedule victim UEs to other carriers or channels away from (not adjacent to) an interfering band, provided that the operator has multiple carriers or channels available for scheduling.

[0074] Fig. 9 illustrates a diagram 900 showing resource reallocation conducted upon identification of a victim UE. A frequency resource 902 allocated to a victim UE is adjacent to an operating band of another operator. Upon identification of the UE as a victim UE, the base station may reallocate resources so as to allocate the frequency resource 906 to the UE or may, if additional bands are available, allocate to the UE the frequency resource 908 in the frequency band 910.

[0075] Fig. 10 illustrates a process 1000 according to an embodiment of the present invention. At step 1002, inter-operator information is exchanged between UEs through device to device communication, suitably in a white space band. At step 1004, upon detection that it is a victim of strong inter-operator interference, the victim UE reports this condition to a base station. At step 1006, upon being informed that a UE is a victim of strong inter-operator interference, the base station sends measurement requirements to its served UEs to allow the performance of inter-operator interfering band measurement. At step 1008, measurement results are reported by one or more associated UEs of the base station. At step 1010, the base station identifies victim UEs, and at 1012, the base station performs resource allocation to avoid or alleviate interference.

[0076] Embodiments of the present invention may also be used to reduce interference in cases of non-contiguous carrier aggregation. In such cases, the D2D information exchanged at step 1002, may comprise jammer carrier information and the resource allocation performed at step 1012 may include directing one or more UEs to retune the radio frequency being used based on the jammer carrier information. Through such radio frequency tuning, a UE can fully exploit a lRx chain typically used for carrier aggregation gain in the non-contiguous carrier aggregation case. Such an approach can provide a good balance between implementation cost and carrier aggregation performance.

[0077] The processes of Figs. 6 and 10 may be considered to illustrate the operation of one or more methods, and a result of execution of a computer program stored in a computer readable memory, and a specific manner in which components of an electronic device are configured to cause that electronic device to operate.

[0078] The process steps shown in Figs. 6 and 10 may also be considered as blocks of a logic flow comprising plurality of coupled logic circuit elements constructed to carry out the associated function(s), or specific result of strings of computer program code stored in a memory.

[0079] Such blocks and the functions they represent are non-limiting examples, and may be practiced in various components such as integrated circuit chips and modules, and that the exemplary embodiments of this invention may be realized in an apparatus that is embodied as an integrated circuit. The integrated circuit, or circuits, may comprise circuitry (as well as possibly firmware) for embodying at least one or more of a data processor or data processors, a digital signal processor or processors, baseband circuitry and radio frequency circuitry that are configurable so as to operate in accordance with the exemplary embodiments of this invention.

[0080] Such circuit/circuitry embodiments include any of the following: (a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and (b) combinations of circuits and software (and/or firmware), such as: (i) a combination of processor(s) or (ii) portions of processor(s)/software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone/UE, to perform the various functions summarized at Figs. 6 and 10 and (c) circuits, such as a microprocessor(s) or a portion of a microprocessor(s), that require software or firmware for operation, even if the software or firmware is not physically present. This definition of 'circuitry' applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term "circuitry" would also cover an implementation of merely a processor (or multiple processors) or portion of a processor and its (or their) accompanying software and/or firmware. The term "circuitry" also covers, for example, a baseband integrated circuit or applications processor integrated circuit for a mobile phone/UE or a similar integrated circuit in a server, a cellular network device, or other network device.

[0081] Fig. 11 illustrates a diagram 1 100, showing information exchanged between and operations performed by D2D UEs 1102 and 1104, a base station 1106, and cellular UEs 1108 and 1110. The D2D UEs perform exchange 1111 of inter-operator interference information, and identification 1112 of strong inter-operator interference is performed by the D2D UE 1104. The D2D UE 1104 reports strong inter-operator interference information 1114 to the base station 1108. The base station makes a decision 1116 that strong interference is present, and performs the sending 1118 of measurement requirements to its cellular UE 1108 and the sending 1120 of measurement requirements to its cellular UE 1110. The UEs 1108 and 1110 respond with performance 1 122 of inter-operator interfering band measurements and reporting 1124 and 1126 of measurement results. The base station 1106 performs victim UE identification Π28 and upon the decision 1130 that the UE 1108 is a victim UE, performs the sending 1132 of resource allocation information.

[0082] Figs. 12 and 13 illustrate additional details of a UE and an eNB that may be configured according to, and employed in, embodiments of the present invention. Fig. 12 illustrates a UE 1200, suitably comprising a transmitter 1202, receiver 1204, radiocontroller 1206, and antenna 1208. The UE 1200 may also suitably comprise a processor 1210, memory 1212, and storage 1214, suitably communicating with one another and with the radiocontroller 1206 over a bus 1216. The UE 1200 may also suitably employ data 1218 and programs 1220, suitably residing in storage 1214 and transferred to memory 1212 as needed for use by the processor 1210.

[0083] Fig. 13 illustrates an eNB 1300, suitably comprising a transmitter 1302, receiver 1304, radiocontroller 1306, and antenna 1308. The eNB 1300 may also suitably comprise a processor 1310, memory 1312, and storage 1314, suitably communicating with one another and with the radiocontroller 1306 over a bus 1316. The eNB 1300 may also suitably employ data 1318 and programs 1320, suitably residing in storage 1314 and transferred to memory 1312 as needed for use by the processor 1310.

[0084] At least one of the programs 1220 in storage of the UE 1214 includes a set of program instructions that, when executed by the processor 1210, enable the device to operate in accordance with the exemplary embodiments of this invention, as detailed above. The eNB 1300 also has software 1320 stored in its storage 1314 to implement aspects of these teachings as detailed above. In these regards the exemplary embodiments of this invention may be implemented at least in part by computer software stored in storage 1214 or memory 1212 which is executable by the processor 1210 of the UE 1200, or by computer software stored in storage 1314 or memory 1312 executable by the processor 1310 of the eNB 1300, or by hardware, or by a combination of tangibly stored software and hardware (and tangibly stored firmware). Electronic devices implementing these aspects of the invention need not be the entire devices as depicted at Figs. 12 and 13, or may be one or more components of same such as the above described tangibly stored software, hardware, firmware and DP, or a system on a chip SOC or an application specific integrated circuit ASIC.

[0085] In general, the various embodiments of the UE 1310 can include, but are not limited to personal portable digital devices having wireless communication capabilities, including but not limited to cellular telephones, navigation devices, laptop/palmtop/tablet computers, digital cameras and music devices, and Internet appliances, as well as the machine-to -machine type devices mentioned above.

[0086] Various embodiments of the computer readable memories 1212 and 1312, and storage 1214 and 1314 include any data storage technology type which is suitable to the local technical environment, including but not limited to semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, removable memory, disc memory, flash memory, DRAM, SRAM, EEPROM and the like. Various embodiments of the processors 1210 and 1310 include but are not limited to general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and multi-core processors.

[0037] Various modifications and adaptations to the foregoing exemplary embodiments of this invention may become apparent to those skilled in the relevant arts in view of the foregoing description. While the exemplary embodiments have been described above in the context of the LTE and LTE-A system, and with systems involving the use of unlicensed frequencies such as frequencies defined under the 802.11 standard, as noted above the exemplary embodiments of this invention may be used with various other types of wireless communication systems.

[0088] Further, some of the various features of the above non-limiting embodiments may be used to advantage without the corresponding use of other described features. The foregoing description should therefore be considered as merely illustrative of the principles, teachings and exemplary embodiments of this invention, and not in limitation thereof.

Claims

What is Claimed is:

1. An apparatus for use in a user equipment comprising:

at least one processor;

at least one memory storing computer program code;

wherein the at least one memory and the computer program code are arranged to, with the at least one processor, cause the apparatus to perform at least:

engaging in device to device communications with another user equipment, wherein the other user equipment belongs to a network of an operator other than the operator of a network in which the user equipment is operating;

determining, based on the information, if the user equipment is a victim of strong inter-operator interference; and

if the user equipment is a victim of strong inter-operator interference, reporting its status as a victim to a base station.

2. The apparatus of claim 1, wherein the device to device communication is conducted over a white space band.

3. The apparatus of claim 1 or 2, wherein the information relating to inter-operator interference comprises identification of an operating band of the network of the other operator.

4. The apparatus of any preceding claim, wherein the information relating to inter-operator interference comprises information relating to received power of the other user equipment.

5. The apparatus of any preceding claim, wherein the inter-operator interference information is requested by the user equipment and the information is received in response to the request.

6. The apparatus of any of claims 1-4, wherein the inter-operator interference information is received by the user equipment upon establishment of device to device communication with the other user equipment.

7. The apparatus of any preceding claim, wherein the apparatus determines if the user equipment is suffering from strong inter-operator interference by evaluating the received power of the user equipment against received power of the other user equipment.

8. The apparatus of any preceding claims, wherein the information relating to inter-operator interference comprises information relating to a jammer carrier.

9. An apparatus for use in a user equipment comprising:

at least one processor;

at least one memory storing computer program code;

receiving measurement requirements from a base station; and

causing the user equipment to perform measurements relating to inter-operator interference on an interfering band of a network in which the user equipment is not operating, wherein the interfering band is one identified based on device to device communications.

10. The apparatus of claim 9, wherein measurements include measurements of received power in a frequency band of the base station's own network.

11. The apparatus of claim 9 or 10, wherein measurements include measurements of received power in an interfering frequency band.

12. The apparatus of any of claims 9-1 1, wherein measurements are performed periodically.

13. The apparatus of any of claims 9-12, wherein measurements are performed upon the occurrence of a triggering event.

14. An apparatus for use in a base station comprising:

at least one processor;

at least one memory storing computer program code;

receiving information from a user equipment identifying the user equipment as a victim of strong inter-operator interference, wherein the status of the user equipment is based at least in part on device to device communication carried out with a user equipment of an operator of a network in which the base station is not operating;

performing control functions to cause the transmission of measurement requirements to at least one user equipment of the base station;

processing measurement information received by the base station from the at least one user equipment to identify user equipments of the base station that are victims of strong inter-operator interference; and

allocating resources so as to reduce inter-operator interference to the at least one user equipment.

15. The apparatus of claim 14, wherein allocating resources comprises scheduling at least one user equipment to use a different frequency resource than currently being used.

16. The apparatus of claim 14 or 15, wherein allocating resources comprises scheduling at least one user equipment to use an operating band different than currently being used.

17. The apparatus of claim 14 or 15, wherein allocating resources comprises retuning a radio frequency being used by at least one user equipment based on jammer carrier information.

18. A method performed in a user equipment comprising:

engaging in device to device communications with another user equipment, wherein the other uses equipment is operating in a network of an operator other than the operator of a network in which the user equipment is operating;

19. The method of claim 18, wherein the device to device communication is conducted over a white space band.

20. The method of claim 18 or 19, wherein the information relating to inter-operator interference comprises identification of an operating band of the network of the other operator.

21. The method of any of claims 16-20, wherein the information relating to inter-operator interference comprises information relating to received power of the other user equipment.

22. The method of any of claims 16-21, wherein the inter-operator interference information is requested by the user equipment and the information is received in response to the request.

23. The method of any of claims 16-22, wherein the inter-operator interference information is received by the user equipment upon establishment of device to device communication with the other user equipment.

24. The method of any of claims 16-23, wherein the determination if the user equipment is suffering from strong inter-operator interference is performed by evaluating the received power of the user equipment against received power of the other user equipment.

25. The method of any of claims 16-24, wherein the information relating to inter-operator interference comprises information relating to a jammer carrier.

26. A method performed by a user equipment comprising:

receiving measurement requirements from a base station; and

27. The method of claim 26, wherein measurements include measurements of received power in a frequency band of the base station's own network.

28. The method of claim 26 or 27, wherein measurements include measurements of received power in an interfering frequency band,

29. The method of any of claims 26-28, wherein measurements are performed periodically.

30. The method of any of claims 26-28, wherein measurements are performed upon the occurrence of a triggering event.

31. A method performed by a base station comprising:

receiving information from a user equipment identifying the user equipment as a victim of strong inter-operator interference, wherein the status of the user equipment is based at least in part on device to device communication carried out with a user equipment of an operator of a network in which the base station is not operating; performing control functions to cause the transmission of measurement requirements to at least one user equipment of the base station;

32. The method of claim 31, wherein allocating resources comprises scheduling at least one user equipment to use a different frequency resource than currently being used.

33. The method of claim 31 or 32, wherein allocating resources comprises scheduling at least one user equipment to use an operating band different than currently being used.

34. The method of claim 31 or 32, wherein allocating resources comprises retaining a radio frequency being used by at least one user equipment based on jammer carrier information.

35. A computer readable medium for use in a user equipment, storing a program of instructions, execution of which by a processor arranges an apparatus of the user equipment to perform at least:

engaging in device to device communications with another user equipment, wherein the other user equipment is operating in a network of an operator other than the operator of a network in which the user equipment is operating;

36. The computer readable medium of claim 35, wherein the device to device communication is conducted over a white space band.

37. The computer readable medium of claim 35 or 36, wherein the information relating to inter-operator interference comprises identification of an operating band of the network of the other operator.

38. The computer readable medium of any of claims 35-37, wherein the information relating to inter-operator interference comprises information relating to received power of the other user equipment.

39. The computer readable medium of any of claims 35-38, wherein the inter-operator interference information is requested by the user equipment and received the information in response to the request.

40. The computer readable medium of any of claims 35-39, wherein the inter-operator interference information is received by the user equipment upon establishment of device to device communication with the other user equipment.

41. The computer readable medium of any of claims 35-40, wherein the apparatus determines if the user equipment is suffering from strong inter-operator interference by evaluating the received power of the user equipment against received power of the other user equipment.

42. The computer readable medium of any of claims 35-41, wherein the information relating to inter-operator interference comprises information relating to a jammer carrier.

43. A computer readable medium for use in a user equipment, storing a program of instructions, execution of which by a processor arranges an apparatus of the user equipment to perform at least:

receiving measurement requirements from a base station; and

causing the user equipment to perform measurements relating to inter-operator interference on an interfering band of a network in which the user equipment is not operating, wherein the interfering band is one identified based on device to device communications,

44. The computer readable medium of claim 45, wherein measurements include measurements of received power in a frequency band of the base station's own network.

45. The computer readable medium of claim 43 or 44, wherein measurements include measurements of received power in an interfering frequency band.

46. The computer readable medium of any of claims 43-45, wherein measurements are performed periodically.

47. The method of any of claims 43-45, wherein measurements are performed upon the occurrence of a triggering event.

48. A computer readable medium for use in a base station, storing a pro gram of instructions, execution of which by a processor arranges an apparatus of the base station to perform at least: receiving information from a user equipment identifying the user equipment as a victim of strong inter-operator interference, wherein the status of the user equipment is based at least in part on device to device communication carried out with a user equipment of an operator of a network in which the base station is not operating; performing control functions to cause the transmission of measurement requirements to at least one user equipment of the base station;

49. The computer readable medium of claim 48, wherein allocating resources comprises scheduling at least one user equipment to use a different frequency resource than currently being used.

50. The computer readable medium of claim 48 or 59, wherein allocating resources comprises scheduling at least one user equipment to use an operating band different than currently being used.

51. The computer readable medium of claim 48 or 49, wherein allocating resources comprises retiming a radio frequency being used by at least one user equipment based on jammer carrier information.