Methods for muting configuration optimization

An efficient way to tame inter-cell interference is by muting selected Base Stations (BSs) in some time-slots to allow users that get strong interference to be served. However finding good muting schemes is a challenge. In this paper we propose two novel methods for finding good BS muting schemes denoted as the complementing method and the sequential method. The methods focus on finding good combinations of muted and un-muted BSs, also referred to as muting configurations. The performance of these methods were compared to the performance of a simple macro muting scheme and to random selection of muting configurations. The comparisons were made for sets of up to 50 muting configurations. The complementing configuration method showed 19% and 9% higher geometrical mean user bitrate than the simple macro muting scheme and the best randomly selected set of muting configurations respectively. The sequential method achieved the best performance, albeit with a cost of higher complexity, which was 40% higher geometrical mean user rate than the simple macro muting scheme and 28% higher than the best randomly selected set of muting configurations. In addition to the performance comparison, the effect of adapting the optimization results to systems having finite muting pattern periods was also studied. It was found that for the complementing and sequential methods using a muting period of K timeslots gives roughly the same performance as that achieved by using K muting configurations and an infinitely long muting period.