Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
  • H04W16/14—Spectrum sharing arrangements between different networks
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L67/00—Network arrangements or protocols for supporting network services or applications
  • H04L67/01—Protocols
  • H04L67/10—Protocols in which an application is distributed across nodes in the network
  • H04L67/104—Peer-to-peer [P2P] networks
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
  • H04W4/06—Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services
  • H04W4/08—User group management
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W72/00—Local resource management
  • H04W72/04—Wireless resource allocation
  • H04W72/044—Wireless resource allocation based on the type of the allocated resource
  • H04W72/0453—Resources in frequency domain, e.g. a carrier in FDMA
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W72/00—Local resource management
  • H04W72/50—Allocation or scheduling criteria for wireless resources
  • H04W72/53—Allocation or scheduling criteria for wireless resources based on regulatory allocation policies

Definitions

• the present invention relates generally to a communication network, and more particularly, to a dynamic frequency reuse method and apparatus for UEs to carry out direct communication, like P2P communication.
• Fig.l illustrates this conventional communication mode used in TD-SCDMA systems, in which UEl and
• UE2 exchange information through UTRAN consisting of a base station transceiver (Node B) and a RNC (radio network controller). But in some cases where two UEs camping in a cell are very close to each other, it can be a more reasonable way for them to communicate directly, and this is the so-called peer-to-peer communication, abbreviated as P2P.
• P2P communication is applied to TDD radio systems where the same carrier frequency is adopted in both uplink and downlink.
• TD-SCDMA system will be taken as an example to describe two P2P communication modes.
• Fig.2 shows a P2P communication mode.
• P2P direct links can be established as represented by the solid line to transfer traffic data between UEl and UE2, whereas UTRAN monitors direct links through control links as represented by the dashed line between it and UEs.
• This P2P communication mode controlled by the base station is called as online P2P communication. Without the relaying of base stations, online P2P communication can save up to 50% radio resource, and meanwhile UTRAN still keeps control of the P2P communication. Descriptions as how to realize online P2P communication are disclosed in the patent applications filed by KONINKLIJKE PHILIPS
• a new communication mode can further be built for the UEs to carry out P2P communication in a self-organizing way without support of base stations, and this is called as offline P2P communication mode.
• Fig.3 shows a schematic diagram of the offline P2P communication mode.
• UEl and UE2 before starting offline P2P communication, UEl and UE2 first register offline P2P communication service at UTRAN in conventional communication mode and obtain the P2P communication identification of their peer.
• the detailed procedure in which a UE obtains the P2P communication identification is described in the patent application filed by KONINKLIJKE PHILIPS ELECTRONICS N.V., Attorney's Docket No. CN030003, along with the present application and incorporated herein as reference.
• two UEs establish P2P communication independently according to the P2P communication identification of their peer obtained during the registration procedure, without control and support of UTRAN.
• UEl and UE2 return to idle mode in conventional communication after the P2P communication is completed.
• the frequency for conventional communication is the radio frequency resource assigned to the cell when the network operator sets up the communication network. Therefore, in the cell, there may be two communications sharing the same frequency: P2P communication and conventional communication.
• interference occurs not only between P2P communication and conventional communication sharing the same frequency, but also between different pairs of P2P communicating UEs sharing the same frequency.
• the interference still lingers between different pairs of offline P2P communicating UEs in a certain area(namely the range that signals transmitted from P2P UEs can reach) outside the coverage area of the communication network.
• Some methods have been put forward to cancel or mitigate interference, such as uplink/downlink synchronization and scrambling code reuse, and so on, but they still fail to fully solve the interference between P2P communication and conventional communication and between pairs of P2P communicating UEs sharing the same frequency.
• An object of the present invention is to provide a dynamic frequency reuse method and apparatus for use in P2P communication, which can effectively cancel interference between P2P communication and conventional communication sharing the same frequency within the coverage area of the communication network.
• a dynamic frequency reuse method for use in P2P communication to be executed in a communication network system comprising: (a) determining a group of candidate frequencies for use in P2P communication in a cell according to the predefined radio resource management scheme of the communication network; (b) sending said group of candidate frequencies to a UE in the cell so that the UE can detect the strength of signals using said group of candidate frequencies, thus to determine the frequency for the UE to carry out P2P communication.
• a dynamic frequency reuse method for use in P2P communication to be executed in a UE comprising: receiving a group of candidate frequencies for the UE to carry out P2P communication sent from a communication network system, wherein said group of candidate frequencies is determined by the communication network system according to the frequency planning information and radio resource management policy information; detecting the strength of signals using said group of frequencies to determine the frequency for the UE to carry out P2P communication.
• a communication network system comprising: a determining unit, for determining a group of candidate frequencies for use in
• P2P communication in a cell according to the frequency planning information and the predefined radio resource management policy information of the communication network; a sending unit, for sending said group of candidate frequencies to a UE in the cell so that the UE can detect the strength of signals using said group of candidate frequencies, thus to determine the frequency for the UE to carry out P2P communication.
• a UE comprising: a receiving unit, for receiving a group of candidate frequencies for the UE to carry out P2P communication sent from a communication network system, wherein said group of candidate frequencies is determined by the communication network system according to the frequency planning information and radio resource management policy information; detecting the strength of signals using said group of frequencies to determine the frequency for the UE to carry out P2P communication
• FIG. 1 is a schematic diagram of the conventional communication mode in the communication system
• Fig. 2 is a schematic diagram showing a TD-SCDMA system adopting P2P communication mode
• Fig.3 is a schematic diagram showing a TD-SCDMA system adopting offline P2P communication mode
• Fig.4 is a schematic diagram illustrating the frequency allocation in a cell in accordance with an embodiment of the present invention.
• Fig.5 is the flowchart diagram showing the dynamic frequency reuse method for use in P2P communication in accordance with an embodiment of the present invention
• Fig.6 is the block diagram illustrating architecture of the UE and network system implementing the dynamic frequency reuse method for use in P2P communication in accordance with an embodiment of the present invention.
• RNC determines the candidate frequencies in each cell to be used for P2P communication according to the frequency planning and radio resource management policy of the current communication network, and broadcasts the candidate frequencies of each cell via base stations to each UE in the cell.
• a UE in the cell detects the strength of signals using the candidate frequencies to communicate, and notifies RNC of the detection result.
• RNC selects a frequency suitable for the UE to carry out P2P communication from the candidate frequencies and sends it to the UE.
• the UE performs P2P communication with this frequency, or namely dynamically reusing frequency resource.
• TD-SCDMA system will be taken as an example below to describe the dynamic frequency reuse method for use in P2P communication as proposed in this invention, in conjunction with accompanying drawings.
• Fig.4 is a schematic diagram showing frequency allocation of a cell in a communication network, and it's supposed that the network operator has 10 frequencies available: Fl, F2, F3,F4, F5, F6, F7, F8, F9 and FlO.
• the frequency reuse factor adopted by the frequency planning of the current network is 7
• Fl is the primary frequency of the serving cell Al of the UE
• adjacent cells of Al are A2, A3, A4, A5 and A6, with primary frequency as F2, F3, F4, F5, F6 and F7 respectively.
• the network operator reserves frequencies F8, F9 and FlO, not yet allocated as primary frequency of any current cell.
• Fig.5 illustrates the procedure of acquiring P2P communication frequency using signaling link between UEl and UTRAN, taking UEl in cell Al as an example.
• UTRAN determines the UE's candidate frequencies for use in P2P communication in cell Al according to the frequency planning information and frequency resource management policy information (step SlO).
• UTRAN When determining the UE's candidate frequencies for use in P2P communication in cell Al, UTRAN first excludes primary frequency Fl for conventional communication in cell Al from the 10 available frequencies Fl to FlO owned by the network operator. Then, according to the frequency planning information and frequency resource management policy, UTRAN further excludes those frequencies that have been defined not to be used for P2P communication. For instance, F 8 is defined as the frequency to be used in emergency, so it's forbidden to be used for P2P communication in cases not urgent; the adjacent cell A2 is a hot-spot cell with extraordinarily high overload of conventional communication traffic and its primary frequency F2 is forbidden to be used as the candidate frequency for P2P communication in other cells. Accordingly, UTRAN can determine that in cell Al the UE can use candidate frequencies F3, F4, F5, F6, F7, F9 and FlO for P2P communication.
• UTRAN After determining the candidate frequencies for the UE to carry out P2P communication in the cell Al, UTRAN encapsulates a list of these candidate frequencies into a system information message, and broadcasts the system information message via a common control channel such as BCCH (step S20).
• BCCH common control channel
• the information entity including these candidate frequencies can alone form a system information message and be broadcasted to the UEs in the cell, or as a part of other system information message, be broadcasted to the UEs in the cell along with other system information messages.
• UTRAN can regularly update and broadcast the system information message including the candidate frequencies according to the management policy information and the operation status of the network (idle or busy).
• UEl reads the system information message over BCCH and extracts the candidate frequencies from the system information message (step S30). According to the extracted candidate frequencies, UEl detects the strength of signals using these candidate frequencies to communicate (step S40).
• signals using these candidate frequencies to communicate can be signals for conventional communication in adjacent cells or signals for ongoing P2P communication including signals for P2P communication in the current cell and signals for P2P communication in adjacent cells as well. So, in addition to detect the pilot signals in adjacent cells to get the strength of signals for conventional communication using the candidate frequencies, UEl also needs to detect the strength of signals for P2P communication using these candidate frequencies in the current cell.
• UEl ranks these candidate frequencies (step S50).
• UEl sends the ranked candidate frequencies as the detection result to UTKAN (step S60). Admittedly, UEl can also send the strength of the signals detected using these candidate frequencies as the detection result to UTRAN directly. Furthermore, UEl can also send its location information to UTRAN if possible, to be taken as a reference when UTRAN determines the P2P communication frequency suitable for UEl.
• UTRAN Upon receipt of the above detection result provided by UEl, UTRAN checks the current operation status of the communication network, that is, current usage of all candidate frequencies. According to the detection result provided by UEl in conjunction with the current operation status of the communication network, UTRAN selects a suitable frequency as UEl 's frequency for P2P communication (step S70). For example, from the current usage of candidate frequencies it can be known that F3 should be excluded from being UEl 's P2P communication frequency among the candidate frequencies for UEs to carry out P2P communication in Al if the number of UEs selecting F3 as P2P communication frequency in Al is above the predefined threshold.
• UTRAN can also refer to UEl 's notified location information such as UEl 's location information obtained by UEl through GPS, to determine P2P communication frequency for UEl.
• UEl 's location information such as UEl 's location information obtained by UEl through GPS
• F4 should be excluded from being UEl 's P2P communication frequency as much as possible if other UEs are using F4 to perform P2P communication around UEl .
• UTRAN After a suitable P2P communication frequency (usually the candidate frequency whose signal strength is the weakest) is selected for UEl according to the detection result notified by UEl in conjunction with the current usage of candidate frequencies and UEl 's location information likely obtained, UTRAN sends the selected frequency to UEl and updates the present frequency usage information of the communication network (step S80).
• UTRAN should choose the frequency whose signal strength is the weakest as UEl 's P2P communication frequency from F5, F6, F7, F9 and FlO as possible as it can on the premise that Fl, F2 and F8 have been excluded and F3 and F4 have been excluded as possible as it can.
• UEl Upon receipt of the suitable frequency sent from UTRAN, UEl establishes P2P communication link with another UE using this frequency (step S90).
• UEl After UEl completes P2P communication using this P2P communication frequency, UEl sends a request for releasing the P2P communication frequency it uses to UTRAN (step SlOO). After receiving the release request, UTRAN reclaims the P2P communication frequency and updates the current frequency usage information of the communication network (step SI lO).
• UEl in Al is taken as an example to describe the procedure as how UEl in online P2P communication mode obtains P2P communication frequency, which is also applicable to the case where a UE to adopt offline P2P communication mode in a cell obtains P2P communication frequency via UTRAN first and then performs offline P2P communication.
• UEl in Al When UEl in Al attempts to perform offline P2P communication, it can choose offline P2P communication frequency independently besides obtaining P2P communication frequency via UTRAN.
• UEl first obtains candidate frequencies that are broadcasted by UTRAN and can be used for the UEs in Al to carry out P2P communication. But different from the above steps, after UEl searches signals according to the candidate frequencies and ranks the signal strength corresponding to the candidate frequencies, the process doesn't go to step S60 afterwards,. : but goes to a step where the candidate frequency corresponding to the signal with the weakest strength detected from the ranked candidate frequencies is determined as the suitable frequency for P2P communication and P2P communication is initiated with another UE using the suitable frequency.
• UEl IfUEl falls outside the network coverage area of Al, UEl itself can decide the frequency for offline P2P communication. In this case, UEl can take advantage of the candidate frequencies obtained via BCCH before leaving the network coverage area or those obtained when registering offline P2P communication service and stored in UEl 's SIM card, to detect the strength of the pilot signals corresponding to the candidate frequencies and that of the signals of the ongoing P2P communication, and choose the candidate frequency corresponding to the weakest signal strength detected (the candidate frequency corresponding to the weakest signal strength is also likely to be the candidate frequency whose signal has not been not found) as the offline P2P communication frequency, thus to mitigate and avoid interference with other UEs in offline P2P communication during P2P communication.
• the above dynamic frequency reuse method for P2P communication is applicable to the case where the planned frequency reuse factor is above 1, and also applicable to the case where the frequency reuse factor is equal to 1 but different frequencies are used in different sectors within the same cell. In the latter case, a different frequency can be selected for the UE in a sector to perform P2P communication dynamically from the frequencies allocated in the adjacent sectors, which is similar to the above method.
• the above dynamic frequency reuse method for P2P communication can be applied in P2P communication between two UEs, and equally can be applied in multi-cast communication between a sending terminal and multiple receiving terminals and direct communication between two UEs in any hop of a multi-hop communication.
• Fig.6 is the block diagram illustrating architecture of the UE and network system in a procedure where the UE performs P2P communication based on the P2P communication frequency acquired from the network system in accordance with an embodiment of the present invention, wherein components same as those in conventional network system and UE are not shown in Fig. 6.
• the communication network system UTRAN 100 comprises: a determining unit 120, for determining candidate frequencies useable for P2P communication of each cell according to the frequency planning information and radio resource management policy of the communication network.
• excluding unit 122 for excluding the frequencies for conventional communication in a cell from the frequencies allocated to the communication network according to the frequency planning information, and excluding those frequencies that can't be used for UEs in the cell to perform P2P communication according to the radio resource management policy information so as to determine the remained frequencies allocated to the communication network as said candidate frequencies that can be used for the UEs in the cell to perform P2P communication.
• Sending unit 130 in UTRAN sends the candidate frequencies decided by determining unit 120 to UE 1 via BCCH.
• detecting unit 20 After receiving unit 10 in UEl receives the candidate frequencies, detecting unit 20 detects the strength of the signals using the candidate frequencies, wherein, the signals of the candidate frequencies include: pilot signals in adjacent cells and P2P communication signals in the cell where UEl camps. Through sending unit 30, UEl notifies UTRAN of the detection result.
• receiving unit 150 in UTRAN After receiving the detection report from UEl, receiving unit 150 in UTRAN provides the detection report to selecting unit 124. According to the detection report, selecting unit 124 selects a suitable frequency from the candidate frequencies in conjunction with the current usage of the candidate frequencies checked by checking unit 140, and sends the suitable frequency to UEl via sending unit 130, so that UEl can perform P2P communication using the suitable frequency.
• receiving unit 10 in UEl Upon receipt of the suitable frequency from UTRAN, receiving unit 10 in UEl provides it to P2P communicating unit 40 so as to carry out P2P communication with another UE. Furthermore, UEl also comprises a determining unit 50, for determining the candidate frequency corresponding to the weakest signal strength as the suitable frequency for P2P communication according to the detection result of detecting unit 20, and providing the P2P communication frequency to P2P communicating unit 40, which then performs P2P communication with another UE using the suitable frequency UEl provides.
• a determining unit 50 for determining the candidate frequency corresponding to the weakest signal strength as the suitable frequency for P2P communication according to the detection result of detecting unit 20, and providing the P2P communication frequency to P2P communicating unit 40, which then performs P2P communication with another UE using the suitable frequency UEl provides.
• the communication network system can dynamically choose a suitable frequency for the UE in the cell to perform P2P communication according to the management policy information, strength of pilot signals of adjacent cells the UE detects, strength of P2P communication signals in the serving cell of the UE and frequency usage of the communication network, so that P2P communication and conventional UPLINK-DOWNLINK communication use different frequencies in the coverage of the serving cell of the UE.
• P2P communication and conventional UPLINK-DOWNLINK communication use different frequencies in the coverage of the serving cell of the UE.
• P2P interference between pairs of P2P communicating UEs caused by reusing frequency is also taken into consideration when selecting P2P communication frequency for the UE. Therefore, using the P2P communication frequency as provided in the method of the present invention, interference between pairs of P2P communicating UEs within the radio range of P2P communication can be avoided and lowered as much as possible no matter inside or outside the coverage area of the communication network and no matter in online or offline P2P communication mode.
• a UE can establish P2P communication link using the dynamically obtained reused frequency and it's not necessary for the network system to allocate new frequency resource for it, thus the capacity of the communication network can be further improved with the dynamic frequency reuse method provided in the present invention.
• the proposed dynamic frequency reuse method and apparatus for P2P communication can be applied in the P2P communication between two UEs, and equally applicable to multi-cast communication between a sending terminal and multiple receiving terminals and direct communication between two UEs in any hop of the multi-hop communication.

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• Mobile Radio Communication Systems (AREA)
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• 2004
  • 2004-08-10 CN CN200410056538.0A patent/CN1735256A/zh active Pending
• 2005
  • 2005-08-03 WO PCT/IB2005/052593 patent/WO2006016330A1/en not_active Application Discontinuation
  • 2005-08-03 JP JP2007525415A patent/JP2008510343A/ja active Pending
  • 2005-08-03 EP EP05780615A patent/EP1779602A1/de not_active Withdrawn
  • 2005-08-03 KR KR1020077003017A patent/KR20070046845A/ko not_active Application Discontinuation
  • 2005-08-10 TW TW094127183A patent/TW200708145A/zh unknown

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