Method and apparatus for handling downlink reference signal interference to PDSCH in long term evolution coordinated multipoint transmission

摘要

A communications system employing CoMP transmission to suppress interference comprises: a CoMP user equipment; and a plurality of base stations, one of the base stations being an associated base station of the CoMP user equipment to transmit data to the CoMP user equipment, the plurality of base stations including multiple CoMP base stations for the CoMP user equipment. The CoMP base stations for the CoMP user equipment transmit CoMP downlink data, including subframes which comprise physical resource blocks having a plurality of resource elements (REs) and cell-specific reference signal (CRS) resource element (RE) locations. PDSCH bit-level muting or puncturing information is determined, based on radio resource management measurement and the subframes sent from the multiple CoMP base stations, to identify PDSCH REs that suffer strong CRS interference transmission from within the multiple CoMP base stations and are to be subjected to one of bit-level muting or bit-level puncturing.

主权项

1. A communications system employing coordinated multipoint (CoMP) transmission to suppress interference, the system comprising:
a CoMP user equipment; and a plurality of base stations, one of the base stations being an associated base station of the CoMP user equipment to transmit data to the CoMP user equipment, the plurality of base stations including multiple CoMP base stations for the CoMP user equipment; wherein the CoMP user equipment performs radio resource management (RRM) measurement on received reference signal (RS) strength for each base station of one or more other base stations in a surrounding area of the CoMP user equipment other than the associated base station; wherein the CoMP base stations for the CoMP user equipment transmit CoMP downlink data, including subframes which comprise physical resource blocks having a plurality of resource elements (REs) and cell-specific reference signal (CRS) resource element (RE) locations; wherein PDSCH (Physical Downlink Shared Channel) bit-level muting or puncturing information is determined, based on the RRM measurement and the subframes which comprise physical resource blocks having a plurality of REs and CRS RE locations sent from the multiple CoMP base stations, to identify PDSCH REs that suffer strong CRS interference transmission from within the multiple CoMP base stations and are to be subjected to one of (i) bit-level muting whereby the PDSCH REs are allocated a number of bits less than the number of bits allocated to normal REs which are not to be muted and data with the bit-level muting is transferred to the CoMP user equipment, or (ii) bit-level puncturing whereby bit Log-Likelihood ratios (LLRs) corresponding to some bits in the PDSCH REs are punctured or discarded from the data received by the CoMP user equipment from the associated base station; and wherein for the bit-level muting, the associated base station identifies the PDSCH REs to be subjected to the bit-level muting and decides muted bit positions of the PDSCH REs to be muted so as to have a number of bits less than the number of bits allocated to normal REs, and the multiple CoMP base stations embed dummy bits in the muted bit positions of the PDSCH REs and simultaneously transmit the CoMP downlink data with the bit-level muting to the CoMP user equipment.