UPLINK POWER-CONTROL FOR TDMA PORTABLE RADIO CHANNELS

Power control based on signal-to-interference ratio (SIR) has been pro posed as a technique for managing co-channel interference in frequency reuse radio systems. Recently, new autonomous power control methods w ere introduced to achieve near-optimum performance without difficult c entralized control proposed earlier. The achievable performance from p reliminary studies appears promising for providing significant increas e in spectrum efficiency. However, the implementation of the SIR-based power control algorithms remains challenging. In this paper, implemen tation of power control that indirectly depends on SIR is discussed. A s an example, a simple closed-loop power control algorithm for the por table transmitter is introduced for TDMA portable radio systems. While it may appear specific for the system considered, the underlying prin ciple and parameters required (i.e., error indicator, received power l evel, and signal quality indicator) are common to the implementation o f digital demodulation circuitry. Computer simulations indicate that S IR level is maintained at a level suitable for sustaining desirable pe rformance. Furthermore, when the power-control updating period is shor t, as in the specific system considered, moderate-rate short-term fadi ng can be tracked and mitigated.