The incorporation of multiple input multiple output (MIMO) schemes in recent wireless communication standards paved the way to exploit the newly introduced dimension (i.e. space) to efficiently cancel the interference...
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ISBN:
(纸本)9781467331227
The incorporation of multiple input multiple output (MIMO) schemes in recent wireless communication standards paved the way to exploit the newly introduced dimension (i.e. space) to efficiently cancel the interference without requiring additional resources. In this paper, we focus on multiple input multiple ouitput (MIMO) multiple access channel (MAC) case and we answer the question about whether it is possible to suppress the interference in a MIMO MAC channel for completely blind users while achieving full-diversity with a simplified decoder in the affirmative. In fact, this goal can be attained by employing space-time block codes (STBC)s that achive full-diversity under partial interference cancellation (PIC). We derive sufficient conditions for a wide range of STBCs to achieve full-diversity under PIC group decoding with or without successive interference cancellation (SIC). Based on the provided design criteria we derive an upper-bound on the achievable rate for a class of codes. A two-user MIMO MAC interference cancellation scheme is presented and proved to achieve full-diversity under PIC group decoding. We compare our scheme to existing beamforming schemes with full or limit feedback.
The Log-domain BCJR algorithm is broadly used in iterative decoding processes. However, the serial nature of the recursive state metric calculations is a limiting factor for throughput increase. A possible solution re...
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ISBN:
(纸本)9781665409438
The Log-domain BCJR algorithm is broadly used in iterative decoding processes. However, the serial nature of the recursive state metric calculations is a limiting factor for throughput increase. A possible solution resorts to high-radix decoding, which involves decoding several successive symbols at once. Despite several studies aiming at reducing its complexity, high-radix processing remains the most computationally intensive part of the decoder when targeting very high throughput. In this work, we propose a reformulation specifically targeting the complexity reduction of the recursive calculation units by either limiting the required number of operations or by selectively removing unnecessary ones. We report a complexity reduction of the add-compare-select units in the order of 50% compared to the recently proposed local-SOYA algorithm. In addition, our results show that several performance/complexity trade-offs can be achieved thanks to the proposed simplified variants. This represents a promising step forward in order to implement efficient very high throughput convolutional decoders.
In this paper, we propose an orthogonal space-time block coding (STBC) for continuous phase modulation (CPM) over frequency-selective channels. The new method maintains the constant envelope and the phase continuity o...
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ISBN:
(纸本)9781467304375;9781467304368
In this paper, we propose an orthogonal space-time block coding (STBC) for continuous phase modulation (CPM) over frequency-selective channels. The new method maintains the constant envelope and the phase continuity of the CPM waveforms by inserting three blocks of data-dependent symbols in addition to a cyclic prefix (CP). At the transmitter, the data blocks are precoded and transmitted in two antennas. And at the receiver, by applying the Laurent decomposition of CPM signals, only linear processing is needed to decode the CPM signal and the decodingcomplexity is much lower than traditional schemes. Simulation results corroborate that the proposed scheme achieves near-optimum error performances.
In this paper, we dedicate to fighting against the multiple carrier frequency offsets (MCFOs) in two-relay decode-and-forward (DF) cooperative networks. A full-rate code named frequency reversal Alamouti code (FRAC) i...
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ISBN:
(纸本)9781467384605
In this paper, we dedicate to fighting against the multiple carrier frequency offsets (MCFOs) in two-relay decode-and-forward (DF) cooperative networks. A full-rate code named frequency reversal Alamouti code (FRAC) is designed for two-relay cooperative orthogonal frequency-division multiplexing (OFDM) networks. Reversal makes the equivalent channel matrix between the relays and the destination complex orthogonalized. The transmission is capable of achieving full diversity through using a zero-forcing (ZF) decoder. Benefiting from FRAC, operations during equalization at the destination are of lowcomplexity. Theoretical analysis and simulation results both demonstrate that the proposed scheme can completely eliminate the effect of MCFOs.
The extended min-sum algorithm (EMS) for decoding non-binary low density parity check (NB-LDPC) codes reduces the decodingcomplexity by truncating the message vector by retaining only the most reliable symbols. Howev...
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ISBN:
(纸本)9781728160429
The extended min-sum algorithm (EMS) for decoding non-binary low density parity check (NB-LDPC) codes reduces the decodingcomplexity by truncating the message vector by retaining only the most reliable symbols. However, the EMS algorithm does not consider that the noise of the received codeword is gradually reduced as the iteration count goes up. In this paper, we propose a low-complexity adaptive EMS algorithm, called threshold-based EMS (TB-EMS). The TB-EMS algorithm has a simple adaptive rule to calculate the new message vector length compared to the A-EMS. The proposed algorithm selects one of two message vector lengths. Experimental results show that the proposed algorithm reduces the decodingcomplexity with minimal performance degradation compared with the EMS algorithm. Further, the decoding performance of the TB-EMS is better than A-EMS.
Due to the high complexity of the pairwise decoding algorithm and the poor performance of zero forcing（ ZF） /minimum mean square error（ MMSE） decoding algorithm, two low-complexity suboptimal decoding algorithms, ...
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Due to the high complexity of the pairwise decoding algorithm and the poor performance of zero forcing（ ZF） /minimum mean square error（ MMSE） decoding algorithm, two low-complexity suboptimal decoding algorithms, called pairwisequasi-ZF and pairwise-quasi-MMSE decoders, are proposed. First,two transmit signals are detected by the quasi-ZF or the quasiMMSE algorithm at the receiver. Then, the two detected signals as the decoding results are substituted into the two pairwise decoding algorithm expressions to detect the other two transmit signals. The bit error rate（ BER） performance of the proposed algorithms is compared with that of the current known decoding ***, the number of calculations of ZF, MMSE, quasi-ZF and quasi-MMSE algorithms is compared with each other. Simulation results showthat the BER performance of the proposed algorithms is substantially improved in comparison to the quasi-ZF and quasiMMSE algorithms. The BER performance of the pairwise-quasiZF（ pairwise-quasi-MMSE） decoder is equivalent to the pairwiseZF（ pairwise-MMSE） decoder, while the computational complexity is significantly reduced.
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