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Recent years have witnessed the unprecedented surge of mobile traffic and base stations (BSs) deployment, which poses severe requirement for future communications systems. Understanding the distribution dynamics of traffic and BSs in time-space domain is of vital importance for better network design and resource management in cellular networks. In this study, a study on the statistical characteristics...
Resource management issue is studied for device-to-device (D2D) communication in cellular networks to improve the overall system capacity and spectrum efficiency. Firstly, a lower bound of the interference distance is derived for a D2D user equipment's according to the transmitter density and the quality of servicerequirement of a D2D pair. By using this distance, an interference set can be chosen...
In recent decades, due to limitation of radio spectrum and increasing users in wireless networks, spectral efficiency has been a considerable issue in literatures. In addition, energy consumption is rapidly increasing in wireless communications due to growing demand for wireless technologies especially cellular networks. Therefore, energy efficiency has become an important issue in such networks....
Rapid growth in data traffic necessitates a proportional growth and improvement in the capacity of cellular networks. A heterogeneous network in which macro cells are overlaid with small cells is a cost efficient and effective paradigm shift for increasing the network traffic capacity. Unplanned deployment of low power base stations with divergent power levels introduces new challenges in heterogeneous...
This paper presents a cluster based resource allocation scheme for allocating physical resource blocks (PRBs) in downlink of OFDMA based cellular systems. The proposed scheme includes two phases of clustering and sum rate maximization. In the first phase users are clustered by using an interference graph in a way that users in each cluster are allocated the same PRB. This interference graph helps...
Device-to-device (D2D) communications as an underlay of a LTE-A (4G) network can reduce the traffic load as well as power consumption in cellular networks by way of utilizing peer-to-peer links for users in proximity of each other. This would enable other cellular users to increment their traffic, and the aggregate traffic for all users can be significantly increased without requiring additional spectrum...
Energy consumption in wireless communication system is rapidly increasing due to the growth in wireless multimedia access. Combating the adverse effects of excessive energy consumption demands for energy-aware system design called green communication, which has become the major focus of many researchers recently. In this paper, we propose user selection and power allocation schemes for a multi-user...
We identify relaying as one of the most effective and enabling components of the LTE-A standard. However, this standard suffers from a major weakness that results from the assumptions that the relaying nodes are static, their locations are known and their number is fixed. While these assumptions facilitate the design of the cellular system, they limit the scope of relay usability. As an alternative,...
As white space, unused local TV spectrum, will be allowed for the broadband Internet access, we can use white space network as the supplementary network of licensed and/or unlicensed access networks such as cellular and WiFi™ networks. Thus, after setting up the connection over a cellular or WiFi™ system, mobile devices equipped with a white space interface will connect to a radio resource management...
This paper focuses on how to associate users with serving nodes in order to achieve improved fairness and efficiency for the cellular networks enhanced with multiple relay nodes (RNs). We first formulate the generalized proportional fair (GPF) problem with the aim of providing fairness for all users served by the evolved node B (eNB) and its subordinate RNs. Routing is incorporated into the GPF problem...
This paper presents a practice oriented approach for an optimization of user scheduling, base stations assignment and beamforming with multipoint transmission in a multiuser multicell scenario using statistical channel knowledge. Especially the cell edge users gain if they are served by multiple base stations (BSs). The max-min beamforming optimization balances the signal to interference and noise...
Cooperative detection involving neighboring base stations is a promising means to increase spectral efficiency in the uplink of cellular systems. To fully utilize the new degrees of freedom that come with base station cooperation, it is essential that a joint scheduler is aware of the interference conditions in all participating cells in order to perform efficient resource and rate allocation. However,...
Energy consumption of information and communication industry has generated increasing concerns recently, aiming at reducing power consumption or increasing energy efficiency. This paper proposes an energy efficient hybrid structure which introduces micro sites into traditional OFDMA cellular systems with only central macro base stations (BSs). The deployment of small and low power BSs alongside the...
In this paper, we apply vector perturbation (VP) precoding to a network multiple-input multiple-output (MIMO) scheme, in which downlink transmissions from base stations are coordinated. We propose a multi-cell VP by introducing a common power scaling factor for all base stations in order to satisfy per base station power constraint. In our scenario, we consider multiple-antenna users with heterogeneous...
Opportunistic beamforming is investigated in the context of multicell LTE uplink resource allocation. A scheduling algorithm based on beam and resource block (RB) allocation with opportunistic beamforming is presented. Beams are formed in a pseudorandom fashion thus allowing users to opportunistically benefit from the antenna gain and interference rejection capabilities. Results show that enhanced...
This paper focuses on the problem of queue-aware resource allocation for OFDMA cellular systems supporting both real-time and non-real-time services. A set of practical algorithms is proposed to solve the problem of maximizing the system utility under the constraints of both system resources and the actual amounts of data to be transmitted in buffers. Moreover, an upper bound is devised to quantify...
Multiuser diversity combined with Orthogonal Frequency Division Multiple Access (OFDMA) are a promising technique for achieving high downlink capacities in new generation of cellular and wireless network systems. The total capacity of OFDMA based-system is maximized when each subchannel is assigned to the mobile station with the best channel to noise ratio for that subchannel with power is uniformly...
An interference management method for coordinating downlink transmission in a Multiple-Input Multiple-Output (MIMO) cellular network is proposed. The problem is to efficiently manage inter-cell interference in a multi-cell environment, by so-called transmitter cooperation, in order to reduce the diminishing effects of interference on the networks performance. To allow for application in deployable...
We consider the problem of fair resource allocation in interference channels, for the case of one-dimensional cells. We propose simple interference channel models based upon the deterministic channel model, assuming zero queuing delay. This enables study of how the interference induces coupling among the rates available in the channels and evaluation of resource allocation. A sequence of models of...
We consider the use of Blind Interference Alignment (BIA) in a cellular environment as a means for supporting downlink Multi-User MIMO (MU-MIMO) transmission without the need for channel state information at the transmitter (CSIT). This “CSIT-blind” characteristic of BIA is of particular interest for Frequency Division Duplex (FDD) systems, since it allows one to eliminate overheads and impairments...
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