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In this paper, a joint channel-and-queue-aware relay selection and resource allocation scheme at the scheduling phase in an OFDMA downlink cellular network is proposed. The scheme can choose the best relay to cooperate and allocate subchannels and power for the source and the relay for the selected packet which can maximize the proposed utility function waiting in the base station. Under the premise...
In order to overcome the indoor coverage problem for residential users, the deployment of home base stations (also referred as home-eNB) has been regarded as a promising solution. However, the unpredictable deployment pattern of home-eNBs makes centralized network planning impractical and requires distributed spectrum planning to achieve effective interference management. In this paper, by enabling...
Current cellular systems suffer from co-channel interference, when simultaneous transmissions in other cells use the same physical resources. Schemes involving cooperation between Base Stations (BS) are currently discussed for further releases of the 3GPP Long Term Evolution (LTE) system as a promising method to mitigate co-channel interference for users located at cell-edge. The BS cooperation approach...
In this paper, a new joint scheduling and hybrid resource allocation method is derived and investigated for a multi-user downlink Orthogonal Frequency Division Multiple Access (OFDMA) system that provides Time Delay-Sensitive services (TDS) and Time Delay-Insensitive services (TDI). A three sectored multi-cellular heterogeneous traffic environment is considered where users are randomly distributed...
In the multi-cell environment, the approaches that are suitable for the single cell scenario may cause excessive interference to other cells and become suboptimal. In this paper, we present a number of receiver-centric power allocation schemes that take into account the detrimental impact of allocated resources to the neighboring cells, and use it as a guideline in determining the appropriate power...
MIMO downlink with base station coordination in a cellular network is considered. In centralized coordinated transmission from a cluster of base stations, the channel state information (CSI) of users needs to be sent to a central processor for user scheduling and resource allocation. Real time CSI feedback from the users to their home base station and from the base stations to the central processor...
Future cellular mobile radio networks will exhibit a much more dense base station deployment than 2nd or 3rd generation communications systems, particularly with regard to traffic coverage. Hence, a significant increase in power consumption of cellular networks can be expected. In order to counter this trend, energy efficiency of such networks should be increased considerably. Concerning energy efficiency,...
In wireless cellular networks, indoor coverage is a problem from the perspective of the service provider. A femto Access Point, also known as femto AP, is utilized to solve the problem. Generally, the femto AP is deployed in a home to support indoor users. Since there might be a small number of users in the home, it could be expected that the traffic load of the femto AP is lower than its wireless...
The next generation of cellular networks (Long Term Evolution) uses SC-FDMA (Single Carrier Frequency Division Multiple Access) on the uplink. In SC-FDMA, the uplink resources assigned to a user are called Resource Blocks (RBs) each of which consists of a set of consecutive subcarriers spanning all symbols available for data. Since at most one User Equipment (UE) is assigned to each RB then uplink...
We consider a wireless system in which a base station allocates bandwidth to users, based on their bandwidth requests in time frames. We design a self-tuning mechanism for the case when users may cheat by requesting more bandwidth than what they truly need, in order to relieve congestion for themselves when the system is overloaded. Our self-tuning mechanism guarantees that the system will automatically...
Self-organization is a key factor for the future evolution of mobile networks, especially for introduction of the new radio standard LTE. Reasons are the increasing complexity, heterogeneity and management effort. Based on an overview about the current state of the art, the self-organization potential for enabling real plug and play functionality, automatic network optimization, improved end-to-end...
Generally, planning and configuring cellular radio networks lead to multi-objective optimization problems with conflicting objectives, e.g., coverage and cost. In this paper, we present an approach to combine those opponents in a closed-form objective for maximization of operator profit by means of joint base station and relay station placement in 4G multi-hop relay networks. The corresponding optimization...
The performance of cellular mobile telephone (LTE) networks is impaired by the amount of interference experienced within the network. In particular, LTE networks are susceptible to inter-cell interference which is experienced when two neighboring cells transmit on the same portion of the frequency spectrum. We propose an adaptive scheduler that can be adopted by LTE networks to minimize inter-cell...
In this paper we discuss some of the benefits and challenges of deploying femtocells in a cellular network. In particular, we focus on the tradeoff between energy efficiency and system performance. With realistic LTE system parameters, we have shown that femtocells can indeed improve energy efficiency of the network. However, this comes with a price - performance degradation due to interference, which...
Coordinated Multi-Point (CoMP) transmission/reception is a candidate technique for increasing cell-average and cell-edge throughputs in next-generation wireless systems. Joint Processing (JP) can enhance CoMP systems' performance, mainly employing precoding algorithms based on channel state information at the transmitter (CSIT). Currently, many research efforts focus on reducing feedback and optimizing...
Performance degradation of Cell Centre UEs (CCUs) and "Interference Flooding" phenomenon may happen in Single-Carrier Frequency Division Multiplexing Access (SC-FDMA) uplinks. To decrease the impact of Interference Flooding and improve the CCUs' throughputs, this paper proposes a UE-Interfering-Area (UIA) based Inter-Cell Interference Coordination (IOC) scheme. Using UIA scheme, the eNodeB...
In this contribution we present the solution of the utility greedy discrete bit loading for interference limited multicell OFDM networks. Setting the utility as the sum of consumed power proportions, the algorithm follows greedy way to achieve the maximum throughput of the system. Simulation has shown that the proposed algorithm has better performance and lower complexity than the traditional optimal...
To overcome the problem that the transmission rate of a multicast channel is limited by the user with the worst channel quality, which causes the total system throughput to be low, the use of both multicast and unicast channels for multicast service is considered in this paper. Unicast channels, in addition to a multicast channel, are allocated to users with signal-to-noise ratios (SNRs) lower than...
In this paper, we investigate the performance of a reuse partitioning (RUP) based cellular uplink system in a multicell environment. In a RUP scheme, a cell is divided into several concentric regions and each region has a different reuse factor. The model presented in this paper accounts for channel selection of a mobile station (MS) using a two-dimensional Markov, and co-channel interference (CCI)...
Femtocell is one of promising key technologies to increase the efficiency and coverage of next generation broadband wireless networks. However, there exists interference problem between femtocells and macrocell due to co-channel operation. In this paper, we propose an efficient frequency resource allocation scheme for newly deployed femtocells in the legacy OFDMA networks in order to maximize the...
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