Microcellular mobile radio spectrum efficiency

The spectrum efficiency of proposed microcellular mobile radio systems using the fast frequency-hopped (FFH) spread-spectrum technique is evaluated. The analysis assumes randomly chosen address vectors, a perfect synchronization at the receiver, and noncoherent detection. The effect of Ricean fading on spectrum efficiency is evaluated. The probability of bit error rate for a noncoherent on-off-keying (OOK) modulation operating in a Ricean fading channel is derived as a closed-form expression. With perfect transmission, where the only degradation is due to mutual interference, the spectrum efficiency is found to be 33.44% at an average bit error rate of 10^-3. In microcellular environments, modeled as white Gaussian noise and Ricean fading with a random-to-specular ratio (K) of -7 dB and a normalized signal-to-noise ratio of 20 dB, the system spectrum efficiency is found to be 27.2% at the same error rate