| 摘要 |
<p>In order to address the problem of RLC layer relaying in the prior art that downlink user data of a user equipment with an access through a relay station may be lost due to a handover, the invention proposes solutions of a method and apparatus for controlling downlink data transmission in a multi-hop relay communication system so that when a next-hop network device of a base station is a relay station, an RLC entity of the base station transmits an indication message to a PDCP entity of the base station, to trigger the PDCP entity of the base station to discard a PDCP SDU corresponding to at least one PDCP PDU, upon reception of a user equipment delivery acknowledgement message from the access relay station to acknowledge delivery of the at least one PDCP PDU to the user equipment. The access relay generates the user equipment delivery acknowledgement message upon reception from the user equipment of positive acknowledgement messages for all the RLC PDUs corresponding to the at least one PDCP PDU. Preferably status information on whether an RLC SDU has been acknowledged, which is buffered between the access relay station and the base station, can be synchronized implicitly.</p> |
