A low-cost multi-user receiver for synchronous CDMA systems

The effect of noise enhancement of the linear decorrelating detector (LDD) is investigated by studying a low complexity receiver for synchronous code division multiple access (CDMA) systems. Using Gold codes as the spreading sequences a general formula of the decorrelating matrix is obtained, which leads to a simplified receiver structure and explicit expression of the bit error rate (BER). It is shown that even with multiple access interference (MAI) reduced, the BER of the system is still dependent on the bandwidth efficiency. For a given bandwidth efficiency the system performance improves when the processing gain is increased.