OFDMA Architectures, Protocols, and Applications

Welcome to this special issue of the EURASIP Journal on Wireless Communications and Networking (JWCN). This special issue is devoted to the topic of the latest research and development on Orthogonal Frequency-Division Multiple Access (OFDMA) from physical and network layers to practical applications. OFDMA technologies are currently attracting intensive attention in wireless communications to meet the ever-increasing demands arising from the explosive growth of Internet, multimedia, and broadband services. OFDMA-based systems are able to deliver high data rate, operate in the hostile multipath radio environment, and allow efficient sharing of limited resources such as spectrum and transmit power between multiple users. OFDMA has been used in the mobility mode of IEEE 802.16 WiMAX, is currently a working specification in 3GPP Long Term Evolution downlink, and is the candidate access method for the IEEE 802.22 “Wireless Regional Area Networks.” Clearly recent advances in wireless communication technology have led to significant innovations that enable OFDMA-based wireless access networks to provide better Quality-of-Service (QoS) than ever with convenient and inexpensive deployment and mobility. However, regardless of the technology used, OFDMA networks must not only be able to provide reliable and high-quality broadband services but also be implemented cost-effectively and be operated efficiently. OFDMA presents many of the advantages and challenges of OFDM systems for single users, and the extension to multiple users introduces many further challenges and opportunities, both on the physical layer and at higher layers. These requirements present many challenges in the design of network architectures and protocols, which have motivated a significant amount of research in the area. Also, many critical problems associated with the applications of OFDMA technologies in future wireless systems are still looking for efficient solutions. The aim of this special issue is to present a collection of high-quality research papers that report the latest research advances in OFDMA communications, networks, systems, and its application in future wireless systems. In this special issue, we selected 17 papers from 36 submissions. The selected papers may be classified into four categories: Channel Estimation, Coding and Modulation, QoS and resource allocation, and Systems and Implementation. In the first part, 4 papers were included. In the second part, there are 3 papers on the coding and modulation. There are 7 papers about QoS and resource allocation management, and 3 papers were selected for systems and implementation issues. A detailed overview of the selected works is given below.