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With the increasing demand on higher data rates to enhance the user experience, one possible solution would be to extend the cellular technology such as LTE toward the unlicensed bands. Initially, LTE was designed based on the frequency re-use factor of one and which has lead to higher capacity in several deployment scenarios. This happens when LTE exclusively uses the licensed spectrum where interference...
Operating frequency bands of the third generation (3G) cellular system and the long-term evolution (LTE) are usually below 3GHz. However, due to the limitation on bandwidth available below 3GHz, the throughput or capacity of 3G and LTE systems cannot be increased easily. This research investigated the feasibility of the application of a wider spectrum in the higher frequency band, such as 6–15GHz...
Massive MIMO is an energy efficient technique which utilizes frequency spectrum efficiently and provides secure and sturdy system. Therefore it is going to be backbone of future broadband network. Multi-cell Massive MIMO system reused orthogonal pilot sequence which results in pilot contamination. Pilot contamination causes poor channel estimation at the BS and degrades the performance of the system...
In mobile satellite communication system, transmission power and frequency band are limited by the satellite inherent characteristic. And spot beam architecture is widely adopted with similar frequency reuse schemes in terrestrial cellular systems, in which the entire spectrum is orthogonally assigned to adjacent beams, resulting in a relatively lower system spectrum utilization. In addition, the...
Distributed antenna systems (DAS) have been shown to considerably outperform conventional cellular systems in terms of capacity improvement and interference resilience. However, the influence of frequency reuse planning on the performance of DAS remains relatively unknown. To partially fill this gap, this paper presents a comparative analysis of the down-link of DAS versus conventional cellular systems...
Distributed antenna systems (DAS) have been shown to considerably outperform conventional cellular systems in terms of capacity improvement and interference resilience. However, the influence of frequency reuse planning on the performance of DAS remains relatively unknown. To partially fill this gap, this paper presents a comparative analysis of the down-link of DAS versus conventional cellular systems...
Cellular networks operating with a frequency reuse factor of one are often interference-limited. For that reason, base station (BS) cooperation techniques aiming at mitigating the effects of interference caused by simultaneous transmissions on the same frequency resources in nearby sectors may considerably improve the system performance. However, for that purpose generally high-capacity backhaul links...
The ever growing demand for high bandwidth allowing broadband applications to be delivered to end-users forces the system operators to seek new ways to increase the bandwidth and capacity of telecommunication systems. It is expected that radio over fiber may be a solution to many problems associated with bandwidth issues. The combination of the two technologies enables use of both their merits: fiber...
We consider the downlink of an Orthogonal Frequency Division Multiple Access (OFDMA) network. OFDMA transmission technology will be used in the next generation of wireless networks such as the LTE (Long Term Evolution) and WiMAX wireless standards. In such a channel, multiple User Equipments (UE) may each be allocated multiple Resource Blocks (RBs) in each frame. A RB is a collection of subcarriers...
We consider the downlink of a multicell OFDM system where the frequency reuse factor is 1. Base-stations cooperate and precode the symbols intended for the mobile stations (terminals) located in different cells and operating on the same frequency, in order to precompensate the co-channel interferences (CCIs). To design the precoders, the CCI coefficients have to be estimated. We assume that the mobile...
A downlink radio resource allocation scheme based on ICI coordination for multi-cell OFDMA system is proposed. By dynamically determining frequency reuse factor, data rate of the users who have bad channel quality is increased. In order to reduce the packet delay of the users with high average packet arrival rate, the average packet arrival rate is used as a factor of the utility function in scheduling...
This paper proposed a joint adaptive soft frequency reuse and virtual cell power control (JAP) algorithm for relay enhanced cellular (REC) system in LTE-A. The JAP algorithm allocates bandwidth to base station and relay node adaptively according to user distribution and target data rate and achieves frequency reuse factor be one among sectors. Furthermore, the JAP algorithm controls transmit power...
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,...
Cooperative MIMO is a key technology for next generation mobile communications. This technique is used to improve cell edge throughput performance. In this paper, we propose a cooperative MIMO scheme with FFR, and evaluate downlink performance of the scheme. We use 3 sector structures per cell. The sector cell is divided into two regions, inner cell and outer cell. The frequency reuse factor (FRF)...
In this paper, we propose an efficient frequency reuse scheme for the downlink environment of multi-cell orthogonal frequency division multiplexing access (OFDMA) systems with 19-cell-structure, that provides an efficiency reduce of the co-channel interference (CCI) at the cell-edge region. It divides each cell into two regions: central region and edge region. The frequency reuse factor (FRF) is 1...
In this paper, a new four-antenna based structure (FAS) is introduced for capacity improvement in future cellular networks with frequency reuse factor of 1. In FAS, each cell consists of one omni-directional antenna located at the cell center and three 120-degree directional antennas located at the cell edge. In order to achieve effective system bandwidth allocation among four antennas, novel spectrum...
In this paper, we investigate the issue of power control and sub-carrier assignment in a downlink OFDMA system. We assume that a certain part of the available bandwidth is likely to be reused by the different base stations (and is thus subject to multicell interference) and that the other part of the bandwidth is shared in an orthogonal way between them (and is thus protected from multicell interference)...
This paper addresses the adaptive allocation of subcarrier, bit and power resources in the downlink of multicell OFDMA systems, where base stations allocate radio resources in a decentralized manner. Our algorithm uses discrete bit-loading values which is more applicable to the practical systems. Noncooperative game theoretic approach is adopted and we first only include the transmit power and throughput...
In this paper, we propose a GAS-CP-CDMA(cyclic-prefix code division multiple access system that uses Sequences with good autocorrelation property) and analyze the uplink signal-to-noise ratio performance of that system. Phase-shifted sequences are used for differentiating users. The signals of the GAS-CP-CDMA system experience no (or very little) interferences from co-cell signals because of the good...
Future mobile communications radio networks, e.g. 3GPP long term evolution (LTE), will typically use an orthogonal frequency division multiplexing (OFDM) based air interface in the downlink. Furthermore, in order to avoid frequency planning, a frequency reuse factor of one is desirable. In this case, system capacity is limited by interference, which is particularly crucial for mobile terminals with...
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