James Paul Seymour

Algorithms for Enhanced Inter-Cell Interference Coordination (eICIC) in LTE HetNets

The success of LTE heterogeneous networks (HetNets) with macrocells and picocells critically depends on efficient spectrum sharing between high-power macros and low-power picos. Two important challenges in this context are: 1) determining the amount of radio resources that macrocells should offer to picocells, and 2) determining the association rules that decide which user equipments (UEs) should associate with picos. In this paper, we develop a novel algorithm to solve these two coupled problems in a joint manner. Our algorithm has provable guarantee, and furthermore, it accounts for network topology, traffic load, and macro-pico interference map. Our solution is standard compliant and can be implemented using the notion of Almost Blank Subframes (ABS) and Cell Selection Bias (CSB) proposed by LTE standards. We also show extensive evaluations using RF plan from a real network and discuss self-optimized networking (SON)-based enhanced inter-cell interference coordination (eICIC) implementation.

Design and analysis of an IEEE 802.16e-based OFDMA communication system

IEEE 802.16e has emerged as a strong candidate standard for future wireless systems primarily because it offers the potential for high spectral efficiency, flexible spectrum options (e.g., 2–6 GHz), scalable carrier bandwidth options (e.g., from 1.25 MHz to 20 MHz), multiple duplexing options (time and frequency division duplex), various subchannelization options, and, unlike its IEEE 802.16 predecessors, mobility. Because of the recent emergence of IEEE 802.16e and the complexity it poses in system analysis, there is little published work in the literature regarding the actual system capacity/throughput performance of IEEE 802.16e for high data rate services. In this paper, we investigate the link and system level performance on the downlink of an IEEE 802.16e-based orthogonal frequency division multiple access (OFDMA) communication system and provide recommendations on high performance IEEE 802.16e system design and deployment configurations. We also propose dynamic resource allocation methods that may be used in OFDMA systems and investigate their performance.

Deprioritization of heavy users in wireless networks

The explosive demand for wireless data services that followed the introduction of application phones continues to create significant challenges for mobile operators. Measurement campaigns indicate that the consumption of wireless network capacity follows a power law where 20 percent of the users consume more than 80 percent of capacity. This creates unfairness among users in terms of the data volume they are allowed to consume and, more important, during congested periods of time it degrades the quality of experience of all the users. As a response, many operators are attempting to control demand by gradually moving away from unlimited data plans with the introduction of volume caps and tiered charging. Many operators throttle the heavy users after they have exceeded their cap, and consider doing the same during times of congestion. This article evaluates the concept of deprioritization of heavy users in wireless networks for congestion management, the difference between deprioritization and throttling, and the enabling technologies to implement the feature in real-world networks.

Self-organizing interference management for LTE

In orthogonal frequency division multiple access (OFDMA) systems such as Long Term Evolution (LTE), it is extremely important to reduce interference between neighboring cells, especially for cell edge users, since the only interference in LTE is inter-cell interference due to the orthogonality of the sub-carriers used in the transmissions. This paper describes a few self-organizing and self-optimizing techniques to manage and reduce this inter-cell interference. These self-optimizing network (SON)-based techniques are inter-cell interference coordination (ICIC) and uplink (UL) interference over thermal (IoT) control. Simulation results are presented showing the improvements that can be obtained with the use of such techniques in interference limited operating scenarios.

The future evolution of wireless mobile communications

At the start of the 21st century, wireless mobile communications has witnessed an unprecedented growth fueled by information explosion and technology revolution. After much fierce technology competitions and uncertainties, two third-generation (3G) wideband standards have emerged to dominate the wireless mobile communications for years to come. They are the CDMA2000 [1] and the universal mobile terrestrial system (UMTS) [2] standards, both of which are based on code-division multiple-access (CDMA) technology. In this paper, we shall indicate how current 2G digital wireless systems might evolve into these 3G systems. We shall examine the likely innovative techniques to be adopted for further evolution of the two systems and the possible capacity gains obtainable by utilizing these techniques. Copyright