Design of carrier frequency offset-spread spectrum (CFO-SS) system using 2.4 GHz ISM band
Design of wireless communications systems with a transmission rate of 6 and 10 Mbit/s is presented for the 2.4 GHz Japanese ISM band, in which a spread spectrum technique named "CFO-SS (Carrier Frequency Offset-Spread Spectrum)" scheme [1]-[3] is employed. In the CFO-SS system, a single PN code is commonly assigned to all the synchronized multiplexed carriers, and the frequency separation between carriers is determined by the transmission rate of each carrier. To realize the CFO-SS system, a timing acquisition and tracking scheme, an important part of the design, is presented first. Next, bit anti packet error performance is investigated under severe multipath environments with/without a RAKE receiver. Degradation by channel bandwidth limitations, frequency inaccuracy of the hardware and co-channel interference (CCI) is also investigated by computer simulation. Simulation results presented confirmed sufficient performance of the CFO-SS system for wireless LAN systems using the 2.4 GHz ISM band.
cfo-ss 2.4 ghz ism band wireless lan