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The resource allocation problem for the downlink of Orthogonal Frequency Division Multiple Access (OFDMA) wireless systems is investigated. It is assumed that the Base Station (BS) consists of multiple antennas in a Distributed Antenna System (DAS), whereas a single antenna is available to each user. Also, the allocation unit is not the subcarrier, as in conventional OFDMA systems, but a set of contiguous...
The DFT-based beamforming weight-vector codebook is considered as an effective design for spatially correlated channels. In this paper, we demonstrate that when the antenna elements are uniformly spaced as well as linearly arranged, and the channels are spatially correlated, the codewords in a DFT-based beaforming weight-vector codebook approximately match the distribution of the optimal beamforming...
The IEEE 802.11n specifies MIMO techniques to enhance data rate in WLANs. However, using carrier sense multiple access with collision avoidance (CSMA/CA), it can support only point-to-point links. On the other hand, it is known that multiuser MIMO techniques significantly increase the spectral efficiency of a network. There are already some enhanced MIMO signal processing techniques available which...
This paper addresses broadband radio access techniques for the long-term evolution (LTE) specified as the Release 8 specifications (Rel. 8 LTE) and LTE-Advanced in the 3rd Generation Partnership Project (3GPP). We first briefly describe the system requirements for the Rel. 8 LTE and LTE-Advanced. Then, we describe wider transmission bandwidths around 100 MHz to satisfy the peak data rate of 1 Gbps...
Modern wireless communication systems employ MIMO and feedback-two properties that make it especially difficult to measure the performance of such systems with reasonable effort in actual outdoor scenarios. In this paper, we will present a time, cost, and manpower efficient measurement approach to evaluate the throughput achieved by such systems. Summer/winter, large distance outdoor-toindoor/outdoor,...
Cellular communication has recently evolved towards data oriented channels with the steady increase of data throughput expected by users. The realization of the mobile Internet requires carefully planned networks and continuous optimization of parameters to achieve the highest efficiency. In most cases cell planning is done by considering the worst case scenarios. However there is an opportunity to...
The distributed base station concept is treated in the LTE scenario. Uplink scheduling in LTE systems with distributed base stations is considered. In the proposed model, users are connected to remote radio heads deployed throughout the cell and connected to a central base station. Centralized and distributed scheduling with a distributed base station are compared to centralized scheduling with a...
The instantaneous capacity of multiple-input multiple-output (MIMO) systems over Rayleigh fading channel is known to follow a normal probability distribution when the number of transmit and receive antennas is large. In this paper, we extend this result for distributed MIMO (DMIMO) systems by deriving a closed-form approximation of the outage probability which becomes tighter as the rate or the number...
In this paper, the wireless mesh backhaul using MIMO systems has been studied. In the mesh networking, information is routed from source to destination over multiple wireless links. On the other hand, using wireless MIMO systems, the channel capacity is significantly increased without additional signal power or bandwidth. We have used the linear programming to optimize the routing determination and...
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