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Sub-sampling in OFDM with Constant Time Signal Recovery

Petrellis N.

Image Processing & Communications

2016

Vol. 21, no. 2

19--32

The sub-sampling method for Orthogonal Frequency Division Multiplexing proposed recently, has been extended in this paper allowing the Analog-to-Digital Converter on the receiver side to operate in low power mode, up to 3/4 of the time. The predictability of the parity patterns generated by the Forward Error Correction encoder of the transmitter, when sparse data are exchanged, is exploited in order to define appropriate Inverse Fast Fourier Transform input symbol arrangements. These symbol arrangements allow the substitution of a number of samples by others that have already been received. Moreover, several operations of the Fast Fourier Transform can be omitted because their result is zero when identical values appear at its input. The advantages of the proposed method are: low power, higher speed and fewer memory resources. Despite other iterative sub-sampling approaches like Compressive Sampling, the proposed method is not iterative and thus it can be implemented with very low complexity hardware. The simulation results show that full input signal recovery or at least a very low Bit Error Rate is achieved in most of the cases that have been tested.

Enhancing Data Transmission Reliability with Multipath Multicast Rate Allocation

Bagherpour M., Alipour M., Kure Ø.

Advances in Electronics and Telecommunications

2011

Vol. 2, no. 3

61--70

In this paper, a multipath routing scheme is proposed for data transmission in a packet-switched network to improve the reliability of data delivery to multicast destinations, and to reduce network congestion. A multi-objective optimization model is presented that utilizes FEC (Forward Error Correction) across multiple multicast trees for transmitting packets toward the destinations. This model assigns the transmission rates over multicast trees so that the probability of irrecoverable loss for each destination and also the link congestion are minimized. We propose a genetic algorithm based on SPEA (Strength Pareto Evolutionary Algorithm) in order to approximate Pareto optimal solutions of this rate allocation problem with a nondominated solution set. Numerical results show that splitting data packets between multiple trees increases reliability and decreases network congestion when compared with the results obtained for transmitting data packets over a single tree.