An all digital packet DS-CDMA transceiver for HFC network upstream transmission

This paper presents the architectures, algorithms, and implementation considerations of an efficient all digital DS-CDMA transceiver used for upstream burst-mode packet transmission in an Hybrid Fiber Coax (HFC) Network, which aims to support integrated services. The transmitter is frequency agile and it supports fine adjustment of signal power and chip delay, which are reserved for MAC ranging in the initialization process. The receiver has corresponding Received Signal Strength Indicator (RSSI) unit as well as frequency offset and chip delay estimation module. To achieve fast acquisition, the receiver employs a parallel correlation FIR filter architecture, and the resultant hardware complexity of the correlator can be reduced by optimizing the structure. Field trials show it can work under a CNR as low as -12 db, and the acquisition can be achieved within 2 data bytes. The architecture is very suited for ASIC design.