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EP-3437371-B1 - METHOD AND APPARATUS FOR PERFORMING PHYSICAL LAYER MOBILITY PROCEDURES

EP3437371B1EP 3437371 B1EP3437371 B1EP 3437371B1EP-3437371-B1

Inventors

  • TOOHER, J. PATRICK
  • PELLETIER, GHYSLAIN
  • PELLETIER, BENOIT
  • MARINIER, PAUL
  • DEENOO, Yugeswar
  • FREDA, MARTINO M.

Dates

Publication Date
20260513
Application Date
20170330

Claims (12)

  1. A method performed by a wireless transmit/receive unit, WTRU, for handover among a set of a plurality of coordinated transmission-reception points, TRPs, the method comprising: measuring a first reference signal, RS, of a first set of the plurality of coordinated TRPs to obtain a first measurement and a second RS of a second set of the plurality of coordinated TRPs to obtain a second measurement; determining that the second measurement is an offset greater than the first measurement; reporting the first measurement of the first RS to the first set of TRPs and the second measurement of the second RS to the second set of TRPs; performing random access by transmitting a preamble using physical random access channel, PRACH, resources of the plurality of coordinated TRPs based on the determination that the second measurement is an offset greater than the first measurement; receiving a random access response, RAR, the RAR comprising a grant to transmit to the coordinated TRPs and scheduling information for an uplink transmission; transmitting the uplink transmission to the first set of the plurality of coordinated TRPs in accordance with the scheduling information; and performing an autonomous handover to transmit to the second set of the plurality of coordinated TRPs rather than the first set of the plurality of coordinated TRPs, based on the first RS, the second RS, and the determination that the second measurement is an offset greater than the first measurement.
  2. The method of claim 1, wherein transmitting the uplink transmission comprises transmitting a radio network temporary identifier associated with the WTRU.
  3. The method of claim 1, wherein performing the measuring includes determining, for a signal received from at least one set of the plurality of TRPs, at least one of: received power, received signal strength, received signal quality, interference, or interference to noise ratio, SNIR.
  4. The method of claim 1, comprising creating and transmitting a TRP list.
  5. The method of claim 1, comprising receiving an indication of a master TRP.
  6. The method of claim 1, comprising indicating to a first TRP of the first set of the plurality of coordinated TRPs that a transmission was made to the second set of the plurality of TRPs.
  7. A wireless transmit/receive unit, WTRU, configured to handover among a plurality of coordinated transmission-reception points, TRPs, the WTRU comprising a processor, the processor configured to: measure a first reference signal, RS, of a first set of the plurality of coordinated TRPs to obtain a first measurement and a second RS of a second set of the plurality of coordinated TRPs to obtain a second measurement; determine that the second measurement is an offset greater than the first measurement; report the first measurement of the first RS to the first set of TRPs and the second measurement of the second RS to the second set of TRPs; transmit a preamble using physical random access channel PRACH resources of the plurality of coordinated TRPs based on the determination that the second measurement is an offset greater than the first measurement; receive a random access response, RAR, the RAR comprising a grant to transmit to the coordinated TRPs and scheduling information for an uplink transmission; transmit the uplink transmission to the first set of the plurality of coordinated TRPs in accordance with the scheduling information; and perform an autonomous handover to transmit to the second set of the plurality of coordinated TRPs rather than the first set of the plurality of coordinated TRPs, based on the first RS, the second RS, and the determination that the second measurement is an offset greater than the first measurement.
  8. The WTRU of claim 7, wherein the processor configured to transmit the uplink transmission comprises the processor being configured to transmit the uplink transmission comprising a radio network temporary identifier associated with the WTRU.
  9. The WTRU of claim 7, wherein the processor configured to measure the first reference signal and the second reference signal comprises the processor being configured to determine, for a signal received from at least one set of the plurality of TRPs, at least one of: received power, received signal strength, received signal quality, interference, or interference to noise ratio, SNIR.
  10. The WTRU of claim 7, wherein the processor is configured to create and transmit a TRP list.
  11. The WTRU of claim 7, wherein the processor is configured to receive an indication of a master TRP.
  12. The WTRU of claim 7, wherein the processor is configured to indicate to a first TRP of the first set of the plurality of coordinated TRPs that a transmission was made to the second set of the plurality of TRPs.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 62/315,080, filed March 30, 2016, and U.S. Provisional Application No. 62/334,630, filed May 11, 2016. BACKGROUND Mobile communications are in continuous evolution and are already at the doorstep of its fifth incarnation - 5G. As with previous generations, new use cases largely contributed in setting the requirements for the new system. It is expected that the 5G air interface will at least enable the following use cases: (1) improved broadband performance (IBB); (2) industrial control and communications (ICC) and vehicular applications (V2X); and (3) Massive Machine-Type Communications (mMTC). The above uses cases are thus translated into many requirements for the 5G interface that should be balanced and optimized. SUMMARY The objectives of the present invention are achieved through the subject-matter of the independent claims 1 and 7, respectively claiming a method performed by a wireless transmit/receive unit, WTRU, for handover among a set of a plurality of coordinated transmission-reception points, TRPs and a corresponding WTRU.Preferred embodiments are set out in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings wherein: FIG. 1A is a system diagram of an example communications system in which one or more disclosed embodiments may be implemented;FIG. 1B is a system diagram of an example wireless transmit/receive unit (WTRU) that may be used within the communications system illustrated in FIG. 1A;FIG. 1C is a system diagram of an example radio access network and an example core network that may be used within the communications system illustrated in FIG. 1A;FIG. 2 is a block diagram of an example of different transmission bandwidths;FIG. 3 is a block diagram of a system bandwidth utilizing a flexible spectrum allocation;FIG. 4 is a block diagram of a frame structure and timing relationships for TDD duplexing;FIG. 5 is a block diagram of a frame structure and timing relationships for TDD duplexing;FIG. 6 shows a flow diagram of a mobility process; andFIG. 7A through FIG. 7D are diagrams of an architecture of TRP mobility in different steps in a mobility process. DETAILED DESCRIPTION FIG. 1A is a diagram of an example communications system 100 in which one or more disclosed embodiments may be implemented. The communications system 100 may be a multiple access system that provides content, such as voice, data, video, messaging, broadcast, etc., to multiple wireless users. The communications system 100 may enable multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth. For example, the communications systems 100 may employ one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), and the like. As shown in FIG. 1A, the communications system 100 may include wireless transmit/receive units (WTRUs) 102a, 102b, 102c, 102d, a radio access network (RAN) 104, a core network 106, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, though it will be appreciated that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and/or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and/or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d may be configured to transmit and/or receive wireless signals and may include user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a pager, a cellular telephone, a personal digital assistant (PDA), a smartphone, a laptop, a netbook, a personal computer, a wireless sensor, consumer electronics, and the like. The communications systems 100 may also include a base station 114a and a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the core network 106, the Internet 110, and/or the other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node-B, an eNode B, a Home Node B, a Home eNode B, a site controller, an access point (AP), a wireless router, and the like. While the base stations 114a, 114b are each depicted as a single element, it will be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and/or network elements. The base station 114a may be part of the RAN 104, which may also include other base stations and/or network elements (not shown), suc