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In this paper, we propose an antenna selection algorithm for down link MIMO SDMA OFDM system. For each user, the data rate corresponding to each transmit antenna is maximized using the optimal bit loading algorithm. A data rate matrix is constructed and used for the antenna selection algorithm assuming the base station (BS) knows the signal-to-noise ratio on all antenna-user pairs of all sub-carriers...
This paper proposes a new wireless scheduling methodology which takes advantage of future predictions of data rate for the several users competing for physical access. Based on a system which allows low-cost 3D mapping of an environment in real-time, the predictions are obtained via either low-resolution path-loss prediction given the physical structure of the surroundings or by reference to data...
An efficient and flexible air interface is the necessary condition for enabling high data rates next generation wireless systems. A practical answer to this need consists in exploiting channel state information at the transmitter for an adaptive and efficient use of the available radio link resources. This paper contributes with a novel strategy for the allocation of the sub-carrier transmit power...
Cyclic prefixed communication systems are generally called discrete multitone (DMT) for wireline systems, and orthogonal frequency-division multiplexing (OFDM) for wireless systems. A cyclic prefix should be as long as the channel impulse response (channel delay spread) to combat inter symbol interference (ISI). If this requirement is not met, a channel shortening equalizer is used to shorten the...
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...
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...
Effects of improved channel estimation are studied for a proposed IEEE 802.11n OFDM MIMO system. Three channel estimation methods are considered: maximum likelihood (ML), time-domain truncation (TDT) and model-based (MB). TDT and MB are particularly useful when the channel delay spread is short. For an MMSE receiver, MB shows a 1-2.5 dB improvement over ML on the packet error rate performance for...
Correlative minimum shift keying (MSK), a second order polynomial modulation scheme known as tamed frequency modulation (TFM), is a constant envelope type of modulation with a perfect peak to average power ratio (PAPR), besides the property of low out of band power. We apply the linearized TFM to the single carrier transmission with frequency domain equalization (SC/FDE) concept. We then obtain a...
In this paper, a novel approach using frame-based iterative channel fading parameters estimation technique from the received data sequence exploiting orthogonal property of the space-time block (STB) code is proposed. For practical implementation of STB code, the receiver requires to estimate these parameters. Regarding this type of estimation, the inherent orthogonal nature of STB code can be exploited...
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