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This paper presents the results from a field measurement campaign that was conducted to provide an understanding of Multiple-Input Multiple-Output (MIMO) performance relative to that of a Single-Input Single-Output (SISO) system in military-type environments. The Space & Terrestrial Communications Directorate (STCD) MIMO system was used to conduct these experiments. The system has two antennas...
Multi-input multi-output (MIMO) cognitive radio (CR) network is an emerging technology which is expected to be a potential solution to enhance the utilization efficiency of the radio spectrum. CR network supports opportunistic spectrum sharing by allowing the secondary users to share the same radio spectrum occupied by the primary users. However, the spectrum sharing by the secondary users should...
In this paper, we focus on the joint stream control and scheduling algorithm based on Multiple Input Multiple Output (MIMO) technique which can significantly improve network capacity without additional increase of bandwidth or transmit power. We propose a stream control algorithm to maximize the network capacity and develop a universal framework for capacity evaluation for MIMO Mesh networks. Simulation...
In this paper, we propose a new relay assisted Hybird-ARQ scheme where the two transmitting nodes (source and relay) and the two received signals (from first transmission and retransmission) are viewed as a virtual MIMO and thus the source can send new codeword when the relay is retransmitting the old codeword. Moreover, to take advantage of time varying channel conditions, the retransmission of relay...
In this paper, we propose a bit and power allocation strategy for adaptive modulation and coding (AMC) based spatial multiplexing multi-input-multi-output (MIMO) orthogonal frequency division multiple access (OFDMA) systems. This strategy aims to maximize the average system throughput by allocating the available resources optimally among the utilized bands depending on the corresponding channel conditions...
We discuss in this paper the effects of antenna efficiency in the presence of a user and on the performance of a multiple-input multiple-output system. The investigation is carried out in different usage scenarios where the antenna efficiency changes significantly from one scenario to another. The propagation channel is defined to include the 3D antenna electromagnetic properties with the 3GPP spatial...
The performance of multi-hop multiple-input, multiple-output (MIMO) communication scenarios is evaluated for space time block coded (STBC) and the proposed distributed cyclic delay diversity (CDD) technique. By increasing the frequency selectivity, multi-stage CDD with low complexity implementation yields significant performance improvement as relaying network. Both diversity techniques based on frequency-correlated...
This paper proposes a differential codebook-based method to reduce the feedback overhead for closed-loop MIMO-OFDM systems. With the assumed multimode transmit precoding, both the number of data streams (rank) and the index of precoding matrix are fed back to the transmitter at each sub-band. By exploiting the channel correlation in frequency domain, an enhanced differential codebook (a subset of...
This paper presents throughput performance of 2 × 2 multiple-input multiple-output (MIMO)-orthogonal frequency division multiplexing (OFDM) using a testbed in line with the Long Term Evolution (LTE) numerology. Then, this paper clarifies the relation among the throughput, modulation schemes and antenna polarization. The field experiments clearly demonstrate that a measured throughput exceeding 200...
In many countries more than 70 % of the traffic on cellular networks originates or terminates inside buildings. Driven by an increasing demand for mobile data services, the iPhone effect, this number is expected to rise even higher within the next years. When rolling out new systems addressing high speed data needs, e.g. LTE or HSPA+, a cost effective solution is explored by extending the outdoor...
In this paper, multiple-input multiple-output (MIMO) layer shifting with cubic metric (CM) preserving precoder and downlink control signal sharing is proposed as a uplink transmission scheme for 3GPP Long Term Evolution (LTE). The design criteria for CM preserving precoder are presented and uplink precoder is designed accordingly. By sharing MCS (modulation and coding scheme) and/or HARQ (hybrid automatic...
The LOS components of the base station (BS) can provide a high SNR to mobile stations (MSs), but they cannot achieve a high spatial multiplexing gain in the MIMO-OFDMA system. The spatial multiplexing gain is obtained by degrees of freedom between MIMO antenna arrays. MIMO channels should be uncorrelated to achieve the maximum degrees of freedom, and it depends on rich scattering environments which...
In time division-high speed packet access plus (TDHSPA+) system, multiple input multiple output (MIMO) technique is adopted to improve spectrum efficiency and transmission reliability. However, most current literature are focused on the large spacing antenna setup, which is impractical for user equipment (UE) because of the size limitation. Therefore, dual polarization antenna scheme is introduced...
In this paper, we investigate carrier frequency synchronization in the downlink of 3GPP Long Term Evolution (LTE). A complete carrier frequency offset estimation and compensation scheme based on standardized synchronization signals and reference symbols is presented. The estimation performance in terms of mean square error is derived analytically and compared to simulation results. The impact of estimation...
This paper addresses the fairness of Medium Access Control (MAC) protocols that are capable of handling interference on the physical layer to a varying extent. The variation addressed is thereby not based on different physical layer techniques applied, but on differing attribute levels of the same physical layer technique. This can e.g., be a varying number of antennas at each node in case of Multiple...
This paper proposes a new double iterative procedure for sum-rate maximization in a Multiuser MIMO system (MU-MIMO). The proposed algorithm is based on joint precoder and decoder optimization involving two different decoding schemes. For that we considered a precoding algorithm namely the iterative SJNR (Signal to Jamming and Noise Ratio) precoder combined with two iterative receivers. The first receiver...
This paper develops the first prototype hardware for TDD/TDMA two-way multi-hop relay network with MIMO network coding, and network throughput is measured in an indoor environment. Since conventional wireless multi-hop relay networks have a drawback of low data rate, TDD/TDMA two-way multi-hop relay networks have been studied as a solution to realize high data rate recently. In these networks, forward...
It has been recognized that a primary method of further enhancing the spectral efficiency of LTE Release-8 is to improve support for multi-user (MU) MIMO transmission in the downlink in an efficient manner. This paper investigates the performance improvements due to the enhanced support of single-cell MU-MIMO within the framework of LTE evolution (specifically LTE Release-9 and Release-10 also known...
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...
This paper proposes suboptimal precoding vector (PV) selection schemes combined with frequency domain scheduling when closed-loop MIMO precoding is adopted in the LTE (Long-Term Evolution)-Advanced uplink based on single carrier-frequency division multiple access (SC-FDMA) radio access. In the proposed schemes, frequency domain channel-dependent scheduling is performed based on a tentatively selected...
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