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InterDigital develops wireless technologies for mobile devices, networks, and services worldwide. InterDigital has licenses and strategic relationships with many of the world's leading wireless companies. Founded in 1972, InterDigital is listed on NASDAQ and is included in the S&P MidCap 400 index.InterDigital has about 20,000 U.S. and foreign issued patents and patent applications. The company employs approximately 200 engineers, and conducts independent research and development in various areas of wireless, including spectrum usage, bandwidth management, video streaming and 5G. The company contributes technologies to various standards bodies, including the IEEE, ETSI and 3GPP.The company is a founding member of the Innovation Alliance - a coalition of entrepreneurial companies that claims to seek to improve the quality of patents granted. Wikipedia.

Wang S.,Nanjing University | Ge M.,Nanjing University | Wang C.,InterDigital Communications
IEEE Journal on Selected Areas in Communications | Year: 2013

Cognitive Radio (CR) is an attractive technology to deal with current spectrum scarcity problem, while cooperative relay can make distributed receivers benefit from spatial diversity and combat severe fading in wireless environment. CR with cooperative relay is potentially a promising paradigm for developing spectrum-efficient wireless systems. In this paper, we study the resource allocation in Orthogonal Frequency Division Multiplexing (OFDM)-based CR networks with cooperative relays. Since the formulated optimization task defines a mixed integer programming problem that is generally hard to solve, we propose a two-stage method to produce near optimal solutions. Particularly, by jointly considering the Signal-to-Noise Ratios (SNRs) of OFDM subchannels and the interferences introduced to primary users, we propose an efficient subchannel assignment scheme for the CR system, as well as transmission mode selection strategy. Furthermore, we develop a fast algorithm to distribute power among subchannels, which can always work out the optimal power allocation with a reasonable complexity by exploiting the structure of the problem. Numerical results show that our proposal can significantly increase the throughput of the CR system compared with other schemes, and the proposed algorithm converges quickly and stably. © 1983-2012 IEEE. Source

Wang S.,Nanjing University | Zhou Z.-H.,Nanjing University | Ge M.,Nanjing University | Wang C.,InterDigital Communications
IEEE Journal on Selected Areas in Communications | Year: 2013

In this paper we study the Resource Allocation (RA) in Orthogonal Frequency Division Multiplexing (OFDM)-based Cognitive Radio (CR) networks, under the consideration of many practical limitations such as imperfect spectrum sensing, limited transmission power, different traffic demands of secondary users, etc. The general RA optimization framework leads to a complex mixed integer programming task which is computationally intractable. We propose to address this hard task in two steps. For the first step, we perform subchannel allocation to satisfy heterogeneous users' rate requirements roughly and remove the intractable integer constraints of the optimization problem. For the second step, we perform power distribution among the OFDM subchannels. By exploiting the problem structure to speedup the Newton step, we propose a barrier-based method which is able to achieve the optimal power distribution with an almost linear complexity, significantly better than the complexity of standard techniques. Moreover, we propose a method which is able to approximate the optimal solution with a constant complexity. Numerical results validate that our proposal exploits the overall capacity of CR systems well subjected to different traffic demands of users and interference constraints with given power budget. © 1983-2012 IEEE. Source

Ye Y.,InterDigital Communications | Andrivon P.,Technicolor
IEEE Multimedia | Year: 2014

This article presents an overview of SHVC, the scalable extension of H.265/HEVC. SHVC adopts a scalable coding architecture with only high-level syntax changes relative to its base codec, which allows SHVC to be deployed with significantly reduced implementation cost. SHVC supports a rich set of scalability features. It also addresses the increasing market demand for higher quality and higher value video content delivery by providing a set of desired scalability features with high coding efficiency. © 2014 IEEE. Source

Xu T.,InterDigital Communications | Xia X.-G.,University of Delaware
IEEE Transactions on Information Theory | Year: 2014

Gomadam recently proposed two distributed interference alignment algorithms, namely the zero-forcing and the maximal signal to interference plus noise ratio (max-SINR) algorithms. Both of them only require local channel state information and no symbol extension is needed. Then, Ning showed that when only one stream of information symbols is sent by each user, interference alignment may achieve receive diversity using the max-SINR algorithm. This result was, however, derived only based on an assumption. In this paper, using a different approach, we prove that interference alignment using the max-SINR algorithm indeed achieves receive diversity without the assumption used by Ning The result in this paper not only completes the proof of the result by Ning , but also generalizes it by allowing more than one stream of information symbols to be sent by each user. © 1963-2012 IEEE. Source

Peng M.,Beijing University of Posts and Telecommunications | Li Y.,Beijing University of Posts and Telecommunications | Zhao Z.,Beijing University of Posts and Telecommunications | Wang C.,InterDigital Communications
IEEE Network | Year: 2015

Compared with fourth generation cellular systems, fifth generation wireless communication systems are anticipated to provide spectral and energy efficiency growth by a factor of at least 10, and the area throughput growth by a factor of at least 25. To achieve these goals, a H-CRAN is presented in this article as the advanced wireless access network paradigm, where cloud computing is used to fulfill the centralized large-scale cooperative processing for suppressing co-channel interferences. The state-of-the-art research achievements in the areas of system architecture and key technologies for H-CRANs are surveyed. Particularly, Node C as a new communication entity is defined to converge the existing ancestral base stations and act as the base band unit pool to manage all accessed remote radio heads. Also, the software-defined H-CRAN system architecture is presented to be compatible with software-defined networks. The principles, performance gains, and open issues of key technologies, including adaptive large-scale cooperative spatial signal processing, cooperative radio resource management, network function virtualization, and self-organization, are summarized. The major challenges in terms of fronthaul constrained resource allocation optimization and energy harvesting that may affect the promotion of H-CRANs are discussed as well. © 1986-2012 IEEE. Source

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