Error statistics of real-time power measurements in cellular channels with multipath and shadowing

Realtime power measurements performed by cellular receivers are essential for power control, handoff and dynamic channel allocation. For best results, the measurement filter bandwidth must be sufficiently narrow to average out multipath fluctuations, yet sufficiently wide to follow shadow fading fluctuations. Two measurement methods and two filter types are considered. It is shown, using standard models for the multipath and shadow fadings, that the decibel measurement error tends to be Gauss-distributed and zero mean. The performance metric then becomes the standard deviation (Δ) of the decibel error, which can be minimized by proper choice of the filter bandwidth. It is found that Δ can be kept to values of 3 dB or lower over a wide range of mobile velocities and shadow fading characteristics. The potential gains in measurement accuracy associated with diversity reception and broadband channels are discussed