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Distributed space-time codes over two asynchronous relays are considered. First, we show that the space-time code proposed in [1] is suitable for asynchronous transmission over two relays. Using tools from division algebra, we study the quadratic form resulting from its determinant and we prove that this code has a non-vanishing determinant over all constellations carved from Zopf[i], and thus is...
This paper focuses on the applicability of bit-interleaved space-time coded modulation with iterative decoding (BI-STCM-ID) to wireless local area networks (WLAN). A new intuitive space-time diversity scheme, which ensures a low error rate for small signal-to-noise ratios (SNR) and good asymptotic performance, is provided. The presented technique can ensure compatibility with todaypsilas WLAN specifications...
In this paper, we consider the problem of space-time (ST) coding with unipolar pulse position modulations (PPM). The proposed code satisfies a large number of construction constraints that render it superior to the existing PPM encoding schemes. In particular, the proposed 2 times 2 code achieves a full transmit diversity order while transmitting at a rate of 1 PPM-symbol per channel use. The proposed...
A constant envelope continuous phase modulation (CPM) class of Multi-Channel (MC) modulations for multi-antenna transmitters is considered. Each receive antenna receives a superposition of CPM waveforms. The useful signal at the receiver spans a curved space - the information waveform manifold (IWM). Particularly it has the form of a cylinder on a cylinder for 2-component CPM signals. At the receiver,...
We present early results from a 4times4 2.4 GHz ISM band multiple-input multiple-output (MIMO) testbed developed at the University of Newcastle for over-the-air evaluation of MIMO algorithms. To provide maximum flexibility for development of 3 GPP Long Term Evolution (LTE) algorithms, the testbed is designed around a field-programmable gate array (FPGA). The testbed features a simple GUI interface...
In this paper, we propose a new multiple-input-multiple-output (MIMO) transceiver for transmitted-reference impulse-radio ultra-wideband (TR-IR-UWB) communications. The proposed scheme is capable of achieving full spatial and multi-path diversity orders while assuring a simple symbol-by-symbol decodability with analog autocorrelation receivers that do not require any kind of channel estimation. This...
In this paper, we propose a low complexity MIMO detection method for double space-time block (D-STBC) coded OFDM system. The proposed MIMO detector involves two step decoding process to efficiently de-correlate spatially-multiplexed / space-time-coded signals. The proposed MIMO detector collects feedback information from interfering spatial domain. Then, interference cancellation is applied once to...
Multipath fading greatly degrades system performance of wireless networks. Conventionally diversity is introduced to mitigate fading. In this paper we study space diversity in multi-hop wireless networks under power constraints. Point-to-point links are extended to group-to-group virtual MIMO links. Then we propose a cross-layer design of MAC and routing that exploits opportunistic cooperation and...
In this paper, we consider a cooperative network with one source, one destination and two relays to bring cooperative diversity. We assume the link between the source and the destination is so bad that we do not consider it. We propose a decode-and-forward (DAF) strategy based on the Alamouti space-time (ST) code. The two relays must recover the transmitted sequence and forward it to the destination...
Recently, we reported a low-complexity likelihood ascent search (LAS) detection algorithm for large MIMO systems with several tens of antennas that can achieve high spectral efficiencies of the order of tens to hundreds of bps/Hz. Through simulations, we showed that this algorithm achieves increasingly near SISO AWGN performance for increasing number of antennas in i.i.d. Rayleigh fading. However,...
Single frequency networks (SFN) in combination with a multi-carrier transmission scheme such as OFDM are often proposed as a means to provide continuous coverage of broadcast applications over a large area. While this combination does succeed in providing continuous coverage, it has certain limitations. Specifically, at points where signals from multiple base-stations are received, the overall signal-to-noise...
This paper considers quantization and exact minimum mean square error (MMSE) estimation of the squared Frobenius norm and the squared spectral norm of a Rayleigh fading multiple-input multiple-output (MIMO) channel with one-sided spatial correlation. The Frobenius and spectral norms are of great importance when describing the achievable capacity of many wireless communication systems; in particularly,...
In this paper, we consider multiuser space-time block codes (STBCs) for 2times2 multiple-input multiple-output (MIMO) uplink transmissions. Using a truncated union-bound (UB) approximation, we propose design criteria of multiuser STBCs for quasi-static fading MIMO multiple access channels (MACs). Next, we demonstrate how, by combining the structure of algebraic perfect STBCs in [10], a family of multiuser...
A result of Zheng and Tse states that over a quasi-static channel, there exists a fundamental tradeoff, known as the diversity-multiplexing gain (D-MG) tradeoff. The quest for space-time codes that achieve D-MG tradeoff has generated numerous works. However, these space-time codes generally result in a pretty high peak to average power ratio (PAR) value on each antenna. In this paper, we propose two...
In receivers, IQ imbalances have significant effects on the performance of data transmission. Comparison of the performance of different types of orthogonal space-time block codes (OSTBC) in the presence of IQ imbalances show that different codes donpsilat have a same behavior. Although most codes have an acceptable performance in low imbalances, they canpsilat work properly in the presence of intensive...
We explicitly construct space-time codes for a multiple access system composed of K users transmitting simultaneously to the base station in block-fading channels. Each user encodes its own data independently without cooperation between users. Our codes design uses the idea of linear dispersion encoding together with circulant matrices assigned to each user that allow low-complexity linear minimum...
In this paper, we propose an asynchronous cooperative scheme with a decentralized relay strategy. The single carrier block transmission (SCBT) technique is used to mitigate the effect of relay synchronization error. By utilizing an orthogonal space-time code with cyclic delay transmission, cooperative diversity can be achieved. Specifically, each relay node transmits a combination of all rows of the...
Distributed MIMO multi-hop schemes can provide high data rates through spatially distributed relaying nodes. The relaying nodes allow the deployment of MIMO techniques to enhance the throughput by utilizing uncorrelated sub-channels. However, the spatial farness of geometrically separated relaying nodes results in different path losses from the nodes of one virtual antenna array (VAA) to the nodes...
Three desirable properties of a four-antenna space-time block code are full rate, full diversity, and single-symbol decodability. Previously reported space-time codes that achieve all three properties do so at the expense of the peak-to-average power ratio (PAPR). A fourth desirable property of a space-time block code is that its PAPR be the same as that of the underlying quadrature-amplitude modulation...
Cooperative Multi-In Multi-Out (MIMO) schemes can reduce both transmission energy and latency in distributed wireless sensor networks (WSNs). When circuit energy is considered in such networks, the total energy consumed as the number of cooperating nodes increases becomes of particular interest. In addition, most of the previous works focused only on space-time-block-code (STBC) schemes and ignore...
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