Evolution of the reverse link of CDMA-based systems to support high-speed data

Development of an upcoming release of the CDMA2000 ∗ family of standards is expected to focus on enhancing the reverse link (RL) operation to support high-speed packet data applications. The challenge is to design a system that yields substantial throughput gain while causing only minimal perturbations to the existing standard. We are proposing a system that evolves features already present in the CDMA2000 Release B and IS-856 (1xEV-DO) standards and reuses concepts and capabilities that have been introduced for high-speed packet data support on the forward link (FL) in Release C of the CDMA2000 standard. The RL of Release C of the CDMA2000 standard supports a relatively slow scheduled operation of this link using signaling messages. Scheduling with shorter latencies can be achieved by moving this functionality to the physical layer. Concurrently, both the FL and RL channel conditions may be tracked, and users may be scheduled based on this knowledge. To further manage the power and bandwidth cost on the FL, that is, of scheduling users' transmissions on the RL, the mobile station (MS) is permitted to operate in either a scheduled mode or an autonomous mode. A capability is provided for the MS station to switch the mode of operation. Performance impact of, and gain from, some of the system features is characterized through simulation results.