Deng Tianle

Joint user association and ABS proportion optimization for load balancing in HetNet

In this paper, a user association scheme for load balancing in a downlink Heterogeneous cellular network (HetNet) incorporating almost blank subframe (ABS) for interference management is proposed. The joint user association and ABS optimization problem is formulated as maximizing a Logarithmic utility function. Since the joint optimization problem is non-convex and NP-hard, the block coordinate descent (BCD) method is employed to decouple the joint problem into two sub-problems (user association and ABS allocation) and solved in an iterative manner to obtain a suboptimal solution. Simulation results show the effectiveness of the proposed algorithm.

A dynamic spectrum re-allocation scheme in GSM and LTE co-existed networks

It is widely accepted that with the rollout of LTE (Long Term Evolution), multiple 3GPP (3rd Generation Partnership Project) networks including GSM (Global System for Mobile communications) and UMTS (Universal Mobile Telecommunications System) will co-exist with LTE for a long time. Fixed spectrum allocation among multi-RAT (Radio Access Technology) networks cannot make sufficient use of spectrum, since spectrum in each network must be conserved to satisfy peak load situations. This paper proposes a scheme called Dynamic Spectrum Re-allocation (DSR) to make spectrum sharing among different 3GPP networks possible. Detailed investigation in the scenario of GSM and LTE co-existed networks is conducted. System simulation shows with the information exchange and inter-RAT interference coordination between two RATs, LTE can efficiently coordinate the GSM interference and make use of GSM spectrum. Even when GSM load is not low, LTE still can achieve throughput gain when using the shared spectrum with DSR. With this mechanism, spectrum usage and system capacity can be improved significantly in the multi-RAT networks.