Efficient Contention Resolution in Highly Dense LTE Networks for Machine Type Communications

In this paper, we propose a solution to efficiently handle the initial access contention for highly dense LTE networks, which still represents a challenge in terms of the high number of devices associated to Machine Type Communications. The analysis is based on the fact that, as the radius of a LTE cell is larger, the number of available preambles generated from a single root sequence is reduced. The current access mechanism, based on frame-slotted ALOHA, does not operate efficiently under these conditions, negatively affecting the access delay and collision probability. We show how the access procedure can be improved by implementing tree-splitting algorithms in order to cope with high number of simultaneous arrivals in large cells, above 5 km in radius. The implementation achieves as much as 85% reduction on the access delay and 54% reduction on energy consumption for cells with radius larger than 39 km.