From humble beginnings in the 1980s with bulky 1G analog handsets, the wireless cellular communications industry now enjoys a major presence in most countries, with nearly 5 billion subscribers worldwide and revenues in the one trillion USD range. Consumer demand for services is expected to grow rapidly in the next few years, fuelled by new applications such as mobile web-browsing, video downloading/streaming, online gaming, and social networking. The commercial deployment of 3G networks began with 3GPP UMTS/WCDMA in 2001 and has evolved into current UMTS/HSPA networks. To maintain a competitive edge, 3GPP UMTS networks need to support higher bit rates, improved spectrum efficiencies, and lower delays, all at a reduced cost. A well-planned and natural evolution to 4G networks is considered essential. Long-term evolution (LTE) and LTE-Advanced are important steps in this transition. LTE technology demonstrations began as early as 2006 and commercial LTE networks are starting to be deployed by wireless carriers worldwide.This special issue consists of five papers. The first three papers focus on LTE: there is a survey paper on resource scheduling and interference mitigation techniques, a paper on resource scheduling for the provision of different services, and a paper on a method for improving the tradeoff between service quality and radio coverage for enhanced multimedia broadcast and multicast service (E-MBMS). The other two papers are focused on LTE-A: one paper discusses distributed algorithms for solving two self-configuration problems and the other examines the performance of decode-and-forward relaying.Resource scheduling and interference mitigation will be instrumental in the success of LTE. In the first paper, "A survey of scheduling and interference mitigation in LTE," Kwan and Leung present an overview of downlink and uplink resource scheduling techniques, including tradeoffs involved in selecting a channel quality indicator reporting scheme. A variety of methods which have been proposed for reducing intercell interference (ICI) in order to improve the link quality for cell-edge users are also described. The paper includes a brief discussion of the challenges for LTEAdvanced network designers.The issue of joint radio resource allocation for multiple services is challenging, as each service is associated with different characteristics and quality of service requirements. In the second paper, "Scheduling for improving system capacity in multiservice 3GPP LTE," Lima et al. address the issue of scheduling algorithms for multiple services in LTE, in which resources are jointly allocated. Their proposed scheme takes into account different traffic characteristics as well as current achieved satisfaction level of each service. Results show that the proposed scheme can provide significant capacity improvement over conventional approaches.Video broadcast and multicast services are expected to play a very important role in future mobile communications. One of the key techniques for improving performance is the use...
