Symbol-by-symbol rate adapting wireless communication systems: architecture

In this paper, we present a symbol-based (SB), dynamic spreading gain control (DSGC) loop for multi-user CDMA wireless systems. Our SB-DSGC loop provides two advantages over other design. First, the transmitter has the flexibility to adjust spreading gain virtually at any time to maintain the fidelity of symbol error rate (SER) or bit error rate (BER) in time-varying channels. Secondary, our DSGC can have very frequent feedback the channel's state information; e.g., at (CSI) every few symbols. Moreover, it allows the station to dynamically adjust spreading gain along with other adaptive transmission resource schemes with seamless effort. One usage of our DSGC is to maintain individual link's BER in the wireless CDMA system operating in time-varying fading channels.