PACKET DATA TRANSMISSION IN CODE-DIVISION MULTIPLE ACCESS COMMUNICATION SYSTEMS

摘要

The present system is split into a physical layer (20), a data link layer, and a network layer (24). The data link layer is further split into three parts, namely, data link control (23), and two medium access control parts (DLC) (21 and 22). The DLC layer (23) is concerned with link establishment, release and maintenance. The lower MAC part (21) may exist in multiple instances, whereas the upper MAC part (22) is unique. Physically, the two MAC parts (21 and 22) are separated on the network side because the upper MAC part resides in a RNC while the lower part exists in each base station. The connectionless packet service (CLPS) entity (25.1) provides the packet radio service to the mobile user and the CLPS entity (25.2) on the netowrk side provides all facilities required for registration and authentication of mobile users, assigning and administrating their VCIs, and interfacing to a packet data network. The CLPS entities (25.1 and 25.2) use the logical link administrators (LLA) (26.x) to initially route messages via a regular dedicated control channel (DCCH) (27.x) to their peer entities. After the MS is attached to the PRCH, all messages exchanged between the CLPS entities (25.x) as well as user data packets are always directed via the respective PRCH (28.x). In this case, the control packets and user data packets are passed through the DLC (29.x) to the packet radio (PR) control entity (30.x). The packets are fragmented and protected with an error control code, e.g. a block code (BC), by a respective unit (31.x) for detecting transmission errors on the receiving side. Then they are convolutionally encoded, interleaved (IL) by the entity (32.x), and transmitted over the PDCH (33). On the receiving side the fragments are reconstructed from the received samples, reassembled to packets, and forwarded to the target CLPS entity (25.2). When the decoder (31.2) detects the receipt of an erroneous packet fragment, an automatic request for repetition (ARQ) scheme provided in the PR control requests its retransmission.