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CSI-RS (Channel State Information Reference Signal) is designed for higher-order MIMO in LTE-A. However, it could be problematic for LTE legacy UEs in a LTE-A network deployed higher-order MIMO because LTE UEs cannot distinguish CSI-RS from effectual data. In this paper, the impact of CSI-RS on LTE UEs are firstly evaluated by both link-level and system-level simulations. The evaluation results show...
It is well known that MIMO-OFDM technology can improve the diversity gain and system capacity, increase spectrum efficiency and overcome frequency selective fading. However, few MIMO testbeds or prototypes have been considered for CMMB standards. In this work, we present a novel 2×2 MIMO structure for CMMB system. A parallel Alamouti coding is designed to decrease the complexity of MIMO implementation...
MIMO radar imaging is receiving a substantial attention, thanks to its high resolution capacity. Whereas, the complexity and the cost of the active devices able to simultaneously transmit and receive signals of each antenna is a disincentive for the expansion of this technology, particularly using UWB signals. In this paper, a passive device is presented to achieve MIMO radar imaging using a single-port...
Wireless video transmission is one of the main applications of wireless local area networks. And high-speed video transmission can be achieved with the application of MIMO-OFDM technologies. But the conventional digital video transmission in MIMO has to degrade performances of all the antennas to be the same as the antenna with the worst channel gain. Based on H.264/AVC and ParCast, a hybrid digital-analog...
Slow decoding convergence and performance loss are two main drawbacks of the conventional variable rate non-binary LDPC codes based on puncturing. To alleviate these problems, we study in this paper the variable rate non-binary LDPC code that has a mother code of high rate and a series of lower rate codes obtained from the concept of shortening. A novel shortening technique to construct variable rate...
This paper investigates the achievable rate of MIMO cognitive radio network when one primary user (PU) and multiple secondary users (SU) are present, where the latter adopt dirty paper coding (DPC) to cancel the interference of PU's transmission at their receivers. Perfect channel state information is assumed at receivers, while only the statistic information of channels are known at the transmitters...
In this paper, explicit channel feedback for MIMO- OFDM systems is investigated. We first show that by exploiting the finite signal space of the channel impulse response, sub-sampling smoothing filter can be designed to achieve both feedback reduction and noise suppression. Secondly, to improve the distribution of the signal to be quantized, it is better to extract the common scaling term from the...
A Multiple Input Multiple Output (MIMO) relay assisted wireless communication system encoded with Turbo- VBLAST codes is studied in this paper. Source is equipped with multiple transmit antennas, relay is equipped with multiple transmit as well as receive antennas and destination is also equipped with multiple receive antennas. Turbo encoder encodes the input bits and then QPSK or 16 QAM or 64 QAM...
For increasing network bandwidth and guaranteeing quality of service, the 4G networks proposes the techniques of MIMO and OFDMA. However, the performance of the 4G specifications is significantly degraded in the high-mobility environment and high communication interference. As a result, a sender easily uses inaccurate modulation and coding scheme (MCS) and improper power allocation for different-priority...
Extending recent findings on the two-user MISO broadcast channel (BC) with imperfect and delayed channel state information at the transmitter (CSIT), the work here explores the performance of the two user MIMO BC, in the presence of feedback with evolving quality and timeliness. Under standard assumptions, and in the presence of M antennas at the transmitter and N antennas per receiver, the work derives...
This paper compares the performance of single user and multiuser with Walsh Hadamard spreading sequences for relay assisted wireless link as well as direct link. Space Time Block Coding (STBC) is used for encoding the information at user's handset and relay. Input information are mapped using Walsh Hadamard spreading sequences and send to a QPSK or 16 QAM or 64 QAM modulator. Modulated symbols are...
Quadrature Orthogonal Frequency Division multiple access (Q-OFDMA) has been renowned as a promising technique which provides a solution to the high PAPR (Peak to average power ratio), sensitivity to carrier frequency offset (CFO) problem and design complexity as introduced by the normal OFDMA systems. Exploiting this Q-OFDMA systems on the Multi-Input Multi-Output (MEMO) architecture, leads to a remarkable...
The Gaussian multiple-input multiple-output two-way relay channel is considered. By applying linear pre- and post-processing, the channel matrices are transformed into triangular form having equal diagonals. Over the obtained triangular channels, dirty-paper coding is applied, yielding parallel symmetric scalar two-way relay channels; thus, reducing the coding task to that of coding over the scalar...
Cooperative communication enables single antenna systems in a multiuser environment to share their antennas and generate a virtual MIMO transmitter that allows them to achieve transmit diversity. Decode and forward full duplex based relay system is considered. The outage probability expressions are derived for full duplex based virtual MIMO relay system with Alamouti space time coding applied in an...
Camera communications is the use of an image sensor to receive LED modulated data. The undersampling properties of UFSOOK allows the encoding of bits at frequency shift ON-OFF keying frequencies that avoid flicker while at the same time being successfully decoded by a low frame rate camera. PWM dimming is supported via data modulation of the PWM frequency, but requires that FEC be added in the form...
The main limitations of wireless transmission are fading and associated reduction in bit error rate. To mitigate these effects several techniques are employed. One method is to employ multiple input multiple output (MIMO) systems. This paper presents performance analysis and a comparative study of different Space Time Block Codes over Rayleigh fading channel of a MIMO system. MIMO systems employing...
This work characterizes the diversity-multiplexing tradeoff (DMT) of MIMO systems with linear precoders. We analyze the cases of zero-forcing (ZF), regularized ZF (RZF), matched filtering and Wiener filtering precoded MIMO systems. We show that MIMO systems with ZF precoding achieve the same DMT as that of MIMO systems with ZF equalizer. When a regularized ZF (RZF) or Matched filter (MF) precoder...
This paper proposes a network-coding (NC)-based multisource repeat-accumulate (RA)-coded cooperative multiple-input multiple-output (MIMO) scheme, where multiple sources transmit their messages to the destination with the assistance from the single relay. The relay cooperates with multiple sources simultaneously via network-coding. It avoids the issues of imperfect timing / frequency synchronization...
The capacity of the K-user fading multiple access channel with multiple antennas and common information is approximately characterized. In this model, any possible common message may exist. While the exact capacity appears to be difficult to characterize, it may be attained to within a gap independent of the power allocation by a simple separable coding scheme.
A new idea of identifying flat-fading MIMO channel by using space-time coding is proposed in this paper. We organize the source sequence into Hankel matrix and transmit each row of which by independent antenna so that the signal gain time diversity and space diversity simultaneously. Channel estimation is considered using primarily the second-order statistics of the data. Based on singular value decomposition...
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