New USF codes for RT-EGPRS systems

In standard GPRS/EGPRS, an RLC/MAC block is interleaved over four TDMA bursts over four consecutive time frames, and the uplink state flag (USF) field is consequently interleaved over four TDMA bursts. This leads to a 20ms USF field decoding delay due to the fact that the USF cannot be decoded until all four TDMA bursts have been received. To reduce this USF decoding delay, a method to transmit the USF with a short interleaving depth over an EDGE system using a new set of USF codes is proposed. These new USF codes compensate for the loss introduced by a reduced interleaving depth for the USF.