WCDMA continues to evolve to support high-bit-rate applications. Highspeed downlink packet access (HSDPA) technology, for example, substantially increases data rates in the downlink. As data rates increase, however, greater self-interference from the dispersive radio channel limits performance. As a consequence, Ericsson has developed advanced receivers for WCDMA terminal platforms and base stations. The authors describe an advanced receiver approach known as generalized Rake (G-Rake) reception. The G-Rake receiver functions like an equalizer, suppressing self-interference. To minimize cost and time-to-market, the receiver architecture builds on the traditional Rake receiver architecture. Tests show that the G-Rake receiver can significantly improve throughput and system capacity for high-bit-rate applications. Ericsson will include G-Rake for HSDPA services starting with its U350 and U360 WCDMA platforms. G-Rake reception is also being considered for other applications. For voice service, for instance, it can increase downlink capacity by 30. Data and voice applications improve when G-Rake reception is used in conjunction with the two-antenna terminal platforms that are part of EMP's technology roadmap. G-Rake will also significantly improve performance on the uplink when data rates exceed 2Mbps in later phases of the enhanced uplink (EUL).
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