Interference management for heterogeneous networks with spectral efficiency improvement

SE is a key characteristic of cellular communication systems. With the explosive growth of mobile data traffic in future wireless networks, the improvement of SE is necessary and it has been the main target in the 3rd Generation Partner Project standard. Considering this, a small cell solution is put forward and widely regarded as a promising technique to enhance SE by deploying low power cells (micro/pico/femto cells) in macrocells. However, with this mechanism cell gains can be severely limited by high inter-cell interference due to the densely deployed small cells. To address this problem, we first browse the major interference management techniques such as interference cancellation, interference coordination, coordinated multipoint transmission and reception, and interference alignment. Then we analyze the challenges when processing interference in a small cell architecture, and we explore the corresponding solutions. Finally, we design a scheme for interference mitigation from both the signaling and data transmission point of views. For the former, power constraint is employed. For the latter, a joint cross-tier and intra-tier interference mitigation sub-scheme is utilized. With this method, cross-tier interference can be alleviated by hybrid spectrum sharing, while intra-tier interference is avoided with orthogonal spectrum allocation. Besides, two methods are employed for exchanging information required in interference mitigation: wireless broadcast channel and UE-assisted relay. Simulations show that our proposed scheme achieves considerable improvement in SE compared to traditional schemes.