Date Added: Nov 2012
Many technologies ranging from advanced physical layer antenna transmission schemes to efficient air-interface resource management schemes have been developed for spectrum efficiency improvement for the future wireless networks. However, most of these technologies quickly reach their theoretical limits without much room for further improvement. In order to meet capacity demands from the explosive data traffic growth, heterogeneous networks with base stations of diverse coverage and transmission powers are expected to achieve a high spectral and energy efficiency. Compared to the traditional homogeneous networks, issues such as mobile association, load balancing and interference coordination need to be studied carefully in order to realize the performance gain in a wireless heterogeneous network.