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Communication over a fading channel in a wireless storage system makes repair transmissions prone to physical layer errors. The repair transmission can be modeled as a multiple access channel (MAC), where multiple helpers are simultaneously communicating to the newcomer node. The existing optimal MAC space-time (ST) codes are, however, practically useless due to exponentially high decoding complexity...
Multiple-input double-output (MIDO) codes are important in future wireless communications, where the portable end-user device is physically small and will typically contain maximum two receive antennas. Especially tempting is the 4×2 channel, where the four transmitters can either be all at one station, or separated between two different stations. Such channels optimally employ rate-two space-time...
For every Gaussian relay network with a single source-destination pair, it is known that there exists a corresponding deterministic network called the discrete superposition network that approximates its capacity uniformly over all SNR's to within a bounded number of bits. The next step in this program of rigorous approximation is to determine whether coding schemes for discrete superposition models...
We investigate the symbol error rate (SER) and outage probability of the cooperative transmission with the decode-and-forward relay protocol over dissimilar Rayleigh fading channels. The technique of orthogonal space-time block coding (STBC) is applied at the links of source-relay, source-destination and relay-destination. Closed-form expressions of outage probability and SER are derived, respectively...
This paper deals with the network spectral efficiency/capacity analysis of multiple-input multiple-output (MIMO) ad hoc network with K simultaneous communicating transceiver pairs in two scenarios; quantized beamforming for achieving finite rate feedback and imperfect channel state information at the transmitter (CSIT). In the quantized beam forming, each receiver chooses the best beamforming vector...
By exploiting properties of the wireless medium, network coding may provide even larger throughput increases for wireless networks than possible for wired networks. In particular, simultaneously transmitted signals are seen as noisy linear combinations at the antennas of receivers. It is thus quite tempting to use the physical layer to directly perform network coding "on the air". However,...
In this paper, an adaptive detection technique for MIMO-OFDM system is proposed. To execute the adaptive detection, existing SMLD technique is considered. The proposed technique selects proper values of V of the SMLD scheme to each subcarrier according to its estimated received power. To estimate the received power, two estimation modes are presented (noise value estimation mode with a preamble and...
Li and Xia have recently investigated the design of space-time codes that achieve full spatial diversity for asynchronous cooperative communications. They show that certain of the binary space-time trellis codes derived from the Hammons-El Gamal stacking construction are delay tolerant and can be used in the multilevel code constructions by Lu and Kumar to produce delay tolerant space-time codes for...
Orthogonal frequency division multiplexing (OFDM) is the modulation scheme of choice for digital video broadcasting-handheld (DVB-H), which is required to operate under high mobility conditions resulting in significant Inter-carrier Interference (ICI). To mitigate ICI, several cancellation schemes have been proposed but they require reliable channel information at the receiver which is quite challenging...
Some communication applications, like multimedia, deliver data of different importance classes allowing unequal error protection (UEP) levels. In this paper, a multiple-input multiple-output (MIMO) system using orthogonal frequency division multiplexing (OFDM) is considered with a new UEP bit-loading algorithm based on the non-UEP algorithm by Chow, Cioffi, and Bingham. In the proposed bit-loading...
A new construction of a full-diversity full-rate space-time block code (FDFR-STBC) is presented in this paper. The design is for 2 transmit antennas and 2 time slots. The code outperforms the previous FDFR-STBC codes in [3], [4], [5], [6] for 1 receive antenna. We reduce the decoding complexity by exploiting the algebraic structure of the code and using the hybrid maximum-likelihood interference cancellation...
This paper studies efficient complex valued matrix manipulations for multi-user STBC-MIMO decoding. A novel method called Alamouti blockwise analytical matrix inversion (ABAMI) is proposed for the inversion of large complex matrices that are based on Alamouti sub-blocks. Another method using a variant of Givens rotation is proposed for fast QR decomposition of this kind of matrices. Our solutions...
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