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In this paper, we propose a distributed adaptive interference coordination algorithm for a practical orthogonal frequency division multiple access (OFDMA)-based mobile cellular systems. The designed algorithm can achieve an efficient frequency reuse for any user distribution and traffic load. Since no a priori frequency planning is required, the minimal coordination between base stations is also achieved...
We consider a coordinated multicell multiple-antenna downlink transmission in a cellular network also known as \textit{network MIMO}, which is expected to play a key role in future broadband cellular systems. While clustered network MIMO is a practical scheme to benefit from multicell cooperation, it still suffers from inter-cluster (uncoordinated) interference especially for the cell-edge users....
In multi-hop wireless networks, the way the network topology is defined has a strong impact on routing. This paper deals with topology control in cellular networks with relays. Several topology control algorithms taken from ad-hoc networks are adapted to cellular networks. Most of the algorithms considered here are based on proximity graphs. Performance analysis is carried out in a realistic scenario...
In modern cellular systems, base station cooperation multiple-input multiple-output (MIMO) in which multiple base stations transmit desired signals to one user is anticipated to alleviate interference at the cell-edge. Cell-edge user is influenced a great deal by interference between different base stations. Inter-cell interference degrades system performance substantially. An interference alignment...
Multiple Input Multiple Output (MIMO) system provides lot of advantages when introduced in a wireless communication system. It helps in increasing system throughput and reducing error rates. Moreover, designing a MIMO system to support both multi-user and multi-cell provides larger increase in system throughput and allows an increase in number of users. This comes at the cost of how to design that...
In this paper, we propose a framework for analyzing downlink performance of cellular CDMA network without considering retransmission protocol in MAC layer. More specifically, we develop a simulation testbed for analyzing broadcast performance of WCDMA network in presence of both PHY layer and application layer forward error correction (FEC) codes only. In physical layer, low density parity check (LDPC)...
This paper is concerned with the game-theory approach in designing the multiuser downlink beamformers in multicell systems. Sharing the same physical resource, the base station of each cell wishes to minimize its transmit power subject to a set of target signal-to-interference-plus-noise ratios (SINRs) at the multiple users in the cell. In that process, each base station determines its optimal downlink...
This paper studies the effects of heterogeneity in DO networks and proposes measures for reducing or removing them. In particular, two types of imbalance, i.e., f-Imbalance and OH-Imbalance are identified and methods for compensating them, i.e., RL padding and AT overhead (OH) channel boost, are proposed. The effectiveness of the proposed methods is demonstrated through both, developing an analytic...
This paper presents system level downlink performance evaluation results for the TDD based LTE-Advanced networks utilizing some of the most recent technologies for mobile systems. The main enhanced technology components used in the systems include multi-user (MU)-MIMO, intra-site coordinated multipoint (CoMP) transmission and space-time-frequency proportional fair scheduling. Performance comparison...
Uplink scheduling in a multicell OFDMA system is considered. A non-collaborative intercell interference avoidance method is proposed, where base stations shut down certain subcarriers in a probabilistic manner based on the received interference level. Proportional fair scheduling is implemented in order to ensure fairness for cell edge users. A low complexity scheduling algorithm is proposed for this...
This paper focuses on two-cell multiple-input multiple-output (MIMO) Gaussian interfering broadcast channels (MIMO-IFBC) with K cooperating users on the cell-boundary of each BS. It corresponds to a downlink scenario for cellular networks with two base stations (BSs), and K users equipped with Wi-Fi interfaces enabling to cooperate among users on a peer-to-peer basis. In this scenario, we propose...
A novel coordinated scheduling algorithm for OFDM-based systems in multi-cell scenario is proposed in this paper. The studied algorithm based on the utility function is general for the downlink of networks. The algorithm coordinates the subcarrier assignment over the BS cluster. We first establish the framework for this inter-cell coordinated optimization problem through utility-based method. The...
We apply constrained optimization techniques to optimally allocate the bandwidth and power to the users in a cellular network. We investigate partial frequency reuse with multiple users in the full and partial frequency regions for inter-cell interference mitigation. We show that the non-convex sum-rate maximization problem becomes convex under certain simplifying assumptions. Moreover, an efficient...
Optimizing the network performance is a key objective for cellular operators as over-provisioning a network is definitely not a cost-effective solution. However the trend for the upcoming 4G networks is to simplify the planning procedure and to improve the spectral efficiency by using agressive frequency reuse schemes, e.g reuse-1, in the downlink. In this paper, we show that this is not a suitable...
Offset QAM orthogonal frequency division multiplexing (OFDM/OQAM) is a promising technique for high data rate next generation cellular systems, operating on highly time-frequency dispersive channels. To combat dispersive channel interference, OFDM/OQAM systems allow very well time and frequency localized prototype functions. The good localization of the prototype function results from the separation...
Multi-cell processing (MCP) is regarded as an effective way for interference mitigation in cellular networks. We propose a joint Base Station (BS) selection and linear precoding design algorithm for the downlink transmission in MCP enabled networks. The algorithm solves a regularized utility maximization problem to find a sparse solution for the precoding matrix. The BS selection is thus based on...
Admission and power control schemes play important roles in deploying cognitive radio technology to cellular networks. In this paper, we propose a method to calculate the power scale factor, introduce two pre-admission control schemes, and reformulate the problem as a multidimensional knapsack problem. In addition, we propose a novel admission and power control scheme called JAPC-MKP. Simulation results...
This paper investigates the uplink throughput of network MIMO cellular systems at low signal-to-noise ratio (SNR). The network is modeled according to Wyner's extended cellular model, with intracell orthogonal medium access control. We derive analytical expressions for the two key low SNR parameters; namely, the minimum required Eb/N0 for reliable communications and the wideband slope, assuming noncooperative...
In this paper we present a novel multi-cell TDD CSI sounding concept for terminals employing multiple antennas. The objective is to support decentralized downlink beam coordination with minimal or no backhaul traffic between the base stations (BS). Each BS makes its own scheduling and precoding decisions independently, based on the locally available CSI and knowledge of the prior scheduling decisions...
In recent years, the problem of designing efficient relaying schemes has attracted much effort within the research community. However, from a practical deployment point of view, many aspects remain unclear. In this paper we endeavour to provide an industrial perspective on this problem. First, we describe the main characteristics and deployment-related aspects of relays. Second, we give an overview...
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