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This paper provides a joint implementation of Fractional Frequency Reuse (FFR) and relays in the downlink of multi-cellular networks like Long Term Evolution (LTE) networks. The forecasted benefits concern inter-cell interference (ICI) mitigation in each cell. Based on this network architecture and related improvements, individual user throughputs and signal to interference plus noise ratio (SINR)...
In this paper, we have proposed secondary user (SU) resource assignment scheme for a multi-hop cognitive radio network. In Multi-hop networks, since each link has different SNR because of their different distance between the stations and some other circumstance, it degrades the end-to-end throughput. To overcome this problem, we have proposed to give a channel priority in each link based on the link...
Many burst construction algorithms for Orthogonal Frequency Division Multiple Access (OFDMA) were proposed. However, these algorithms do not meet the uplink burst characteristics specified in the IEEE 802.16 standard. This paper therefore proposes the Best Sub channel Oriented algorithm (BSO). BSO not only complies with uplink burst characteristics, but also obtains high throughput by considering...
Frequency-domain scheduling and rate adaptation have helped next generation orthogonal frequency division multiple access (OFDMA) based wireless cellular systems such as Long Term Evolution (LTE) achieve significantly higher spectral efficiencies. To overcome the severe uplink feedback bandwidth constraints, LTE uses several techniques to reduce the feedback required by a frequency-domain scheduler...
One of the most important challenges is how to manage inter-cell interference. Special care has to be taken regarding voice traffic which has more strict requirements on delay and packet loss. The goal of inter-cell interference coordination schemes is to decrease inter-cell interference and get higher cell throughput, so we evaluated the performance of inter-cell interference coordination schemes...
In this paper, we propose a complete radio resource management procedure for best-effort (BE) service in OFDMA systems, which improves the system fairness with graceful throughput degradation compared to the derived analytical upper bound of the system throughput. By the proposed bandwidth and power allocation algorithms, the user in the worst channel environment has almost the same probability of...
Multi-cell cooperative transmission schemes are considered as promising candidates in future 4G wireless networks (LTE-Advanced) to combat the inter-cell interference that degrades the cell-edge throughput performance. An efficient proportional fair (PF) scheduling algorithm for Orthogonal Frequency Division Multiple Access (OFDMA) based cooperative cellular networks is proposed. A PF metric maximization...
A unique frequency reuse scheme by means of cell sectorization is proposed in this paper that reuses effectively a given frequency resource in a cellular environment. The key concept is to find a scheme that controls interferences among neighboring cells in a systematic manner while achieving high frequency reuse factor. Based on, user distribution in a cell, two problems are investigated. First,...
In the heterogeneous networks, radio resource management (RRM) plays an important role to utilize the potential network diversity. In this paper, we study the RRM strategy in the heterogeneous networks involved with an orthogonal frequency division multiple access (OFDMA) network, with the aim of maximizing the minimum user throughput. An analytical model which reflects the feature of heterogeneous...
Inner cell interference (INCI) is avoided in common multicell orthogonal frequency division multiplex access (OFDMA) systems but inter cell interference (ICI) still exist. The system throughput is severely degraded by ICI, especially at cell edge. Several schemes have been proposed to handle this problem by coordinating the way to allocate spectrum resource to each cell. Since the allocation of spectrum...
Fourth generation (4G) mobile access is drawing particular attention as it promises to deliver high data rates and reliable coverage for broadband wireless access. In this paper, Orthogonal Frequency Division Multiplexing Access (OFDMA) and Multi-Carrier Code Division Multiplexing Access (MC-CDMA) are investigated to highlight their strengths and weaknesses as candidates for 4G wireless access. Using...
This paper presents a novel distributed framework to decide the spectrum assignment in a primary cellular radio access network. The distributed nature of the framework allows each cell to autonomously decide (by means of machine learning procedures) the best frequencies to use in order to maximize spectral efficiency, preserve quality-of-service, and generate spectrum gaps, so that secondary cognitive...
In conventional multicell OFDMA systems, generally there is no inner cell interference (INCI). The system throughput is severely degraded by inter-cell interference (ICI), especially at cell edge. To satisfy the performance requirement, ICI must be mitigated effectively. Several schemes have been proposed to handle this problem by coordinating the way to allocate spectrum resource to each cell. Since...
Channel-aware scheduling is one of the advanced features introduced in the uplink of long term evolution (LTE) in order to improve the system spectral efficiency. In the uplink of LTE channel-aware scheduling is possible thanks to the transmission of sounding reference signals. In this paper the performance of frequency and time domain scheduling in LTE uplink is investigated. In particular, we focus...
Soft frequency reuse is a strong tool for co-channel interference mitigation in cellular OFDMA/LTE networks. The performance of such networks significantly depends on the configuration of the power masks that implement the soft frequency reuse patterns. In this paper, we investigate the performance of different power mask configurations against the optimal case, in which a central entity optimally...
Fractional frequency reuse (FFR) is often used in interference-limited systems to improve coverage in cellular networks. Its cost is reducing the amount of available resources. In this paper, we intend to propose the FFR scheme by introducing the concept of normalized spectral efficiency (nSE). With the optimal frequency reuse factor (FRF), the FFR scheme can maximize the system SE with throughput...
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