Shared channels for packet data transmission in W-CDMA

One of the targets for a wideband CDMA (W-CDMA) system is to provide an efficient transfer of low bit rate to very high bit rate packet data services. A shared channel concept has been proposed for both the downlink and uplink channels that is better suited for bursty packet data traffic. The shared channels allows UEs to transmit and receive data bursts at high rates by using short leases on the radio resource thereby lowering the overall delay by taking the greatest advantage of statistical multiplexing. The high rate bursts require the network tightly manage its resources to insure that the appropriate OVSF codes are assigned on the downlink and the aggregate interference does not exceed the noise rise on the uplink. In both cases, the network must convey the new assignments on a frame by frame basis. In this paper, packet data transmission using both downlink shared channel (DSCH) and uplink shared channel (USCH) is discussed for a W-CDMA system