Hybrid division cooperative transmission scheme for LTE enterprise femtocell networks

In this paper, we propose a hybrid division cooperative transmission (HDCT) scheme for system throughput enhancement in enterprise femtocell systems. In HDCT scheme, a cooperative transmission (CT) scheme is applied to user equipments (UEs) located at the edge of a serving femtocell base station (fBS), whereas conventional scheme is applied to UEs located near the fBS. In the zone where CT is applied, a UE is capable of receiving desired signal from serving fBS as well as from an adjacent fBS. Thus, the UE achieves an improved signal to interference plus noise ratio (SINR) by using two time synchronized signals from two adjacent fBSs. Performance of the proposed scheme is evaluated in terms of call level quality of service (QoS) (i.e., call blocking probability) and packet level QoS (i.e., outage probability). We first measure the resource utilization and call blocking probability for the downlink channel for various offered load. Based on that, we obtain the outage probability and effective throughput of the system by computer simulations. Finally, the results of the simulation yield the optimum hybrid zone for achieving the maximum system throughput.