The following abbreviations are utilized herein:
3Gthird generation of GSM-based mobile networks3GPPthird generation partnership projectBSbase stationCDMAcode division multiple accessCQIchannel quality indicatorDLdownlink (Node B to UE)E-UTRANevolved universal terrestrial radio access networkFDMAfrequency division multiple accessGIguard intervalGSMglobal system for mobile communicationsHARQhybrid automatic repeat-requestIMT-Ainternational mobile telephony-advancedLTElong term evolution of UTRANMBMSmultimedia broadcast/multicast service (3GPP)Node Bbase stationOFDMAorthogonal frequency division multiple accessPARpeak-to-average ratioPARRpeak-to-average ratio reductionRANradio access networkSFNsingle frequency networkTAtiming advanceTDDtime division duplexTDMAtime division multiple accessUEuser equipment, such as a mobile station or mobile terminalULuplink (UE to Node B)UTRANuniversal terrestrial radio access networkWANwide area networkWCDMAwideband code division multiple accessWiMAXworldwide interoperability for microwave access (IEEE 802.16 standard)WLANwireless local area network
The use of relays and co-operative diversity is being considered for the next generation of wireless communication systems, such as for E-UTRAN (also referred to as LTE or UTRAN-LTE) and in IMT-A research. While some investigations have focused on fixed relay stations (i.e., where the relay stations are considered a part of the RAN), the use of UEs as relay stations is also being considered, particularly for the UL. In the UL, one aspect of UE relaying is that a UE source may transmit data directly to a Node B destination in a conventional manner and also transmit to the Node B indirectly via a number of relays. At the Node B destination, joint decoding may be performed in order to combine the received signals
It is known in the art, for example, to use TA with a TDD system. Reference in this regard may be made to Section 6.5 of 3GPP (S1.24), V0.1.0, “TDD, Physical Layer Procedures Description,” TSG RAN WG1#2 (99)130, February 1999. As described in S1.24, the timing of transmissions from a UE are advanced with respect to the timing of signals received from the Node B to compensate for round trip propagation delay. The Node B determines the TA for the UE by measuring the timing of a transmission from the UE. The Node B subsequently signals the UE its TA.
In the development of E-UTRAN, it is presently assumed that the UL will contain both TDMA and FDMA aspects. Furthermore, and at least partially due to the TDMA aspects, the use of TA in the UL is similarly anticipated. Reference in this regard may be made to Sections 7.2 and 13.9 of 3GPP TR 25.912, V7.1.0, 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Feasibility study for evolved Universal Terrestrial Radio Access (UTRA) and Universal Terrestrial Radio Access Network (UTRAN) (Release 7),” September 2006.