Estimation of Uplink WCDMA Load in a Single RBS

The measurement of uplink load is important for the scheduling of enhanced uplink channels in WCDMA systems. This measurement is particularly difficult since the thermal noise power floor is unobservable when using power measurements in a single base station. The problem is due to the neighbor cell interference. The paper proposes a work around, using a novel algorithm for soft Bayesian estimation of a conditional probability distribution of the minimum of filtered power samples, this minimum approximating the thermal noise power floor of the digital receiver. The load can then be estimated from the total wideband power of the cell and the estimated minimum. The discretized conditional pdf is one-dimensional - hence the algorithm has a low complexity. Details of the implementation are described in the paper, together with measured results.