Constellation subset selection is a new topic emerging in the adaptive modulation communications. How to choose the subset of the original constellation phasers appears to be challenging and interesting to the researc...
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Constellation subset selection is a new topic emerging in the adaptive modulation communications. How to choose the subset of the original constellation phasers appears to be challenging and interesting to the researchers. There hardly exists any literature which studies the feasibility and the solution of constellation subset selection in details. Here we dedicate to this problem in both theoretical exploration and algorithm design. In this paper, we introduce the detailed theoretical analysis regarding the mathematical properties of the commonly-used constellations and then facilitate the constellation subset selection problem. Based on our problem formulation, we design two algorithms to solve this problem thereby. Our complexity analysis evinces the effectiveness of the proposed algorithms.
In this paper, we study code constructions over the finite ring M 2 (F 2 ), the ring of 2times2 matrices with coefficients in the finite field F 2 . We show how they can be related to classical codes over F 4 . We pro...
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In this paper, we study code constructions over the finite ring M 2 (F 2 ), the ring of 2times2 matrices with coefficients in the finite field F 2 . We show how they can be related to classical codes over F 4 . We provide as application the design of outer codes for 2 times 2 space-time coded modulation, when the inner code is the so-called Golden code.
The performance of on-off keying (OOK) based wireless infrared transmission can be seriously deteriorated by the so called ldquotransient baseline wanderrdquo, which is caused by the inherent high-pass characteristics...
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The performance of on-off keying (OOK) based wireless infrared transmission can be seriously deteriorated by the so called ldquotransient baseline wanderrdquo, which is caused by the inherent high-pass characteristics of the receiver. The signal distortion induced by such an impairment can be mitigated by using a line code. In this paper, we propose two 8B10B line coding schemes for Gbps wireless infrared line-of-sight (LOS) transmission based on the non-return to zero (NRZ) OOK modulation: the classic IBM code and the concatenated flipped bit insertion (CFBI) code. The latter is newly designed and enables simpler and more effective encoding and decoding algorithms. Simulation results demonstrate a small susceptibility to the transient baseline wander. Both codes are DC-balanced and offer regular state transitions.
This paper presents the programming and use of TMS320F2812 digital signal processor (DSP) in generating the digital pulse width modulation (DPWM). The structure and functions of eZdsp 2812 board used in this work is e...
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ISBN:
(纸本)9781424451869;9781424451876
This paper presents the programming and use of TMS320F2812 digital signal processor (DSP) in generating the digital pulse width modulation (DPWM). The structure and functions of eZdsp 2812 board used in this work is explained briefly and the steps need to be taken for the programming is explain in detail to control the frequency, the duty cycle and dead band of the generated PWM. The PWM generated by DSP from programming can be used to control and regulate power electronic converters.
Adaptation to changing conditions in the transmission medium is a particularly desired property in optically-routed networks due to their heterogeneous nature. Toward this goal, we propose in this paper rate-adaptive ...
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ISBN:
(纸本)9781424448258
Adaptation to changing conditions in the transmission medium is a particularly desired property in optically-routed networks due to their heterogeneous nature. Toward this goal, we propose in this paper rate-adaptive polarization multiplexed coded multilevel modulation schemes based on non-binary quasi-cyclic low-density parity-check (LDPC) codes and coherent detection. The proposed scheme can support data rates at 100 Gb/s and beyond while offering comparably better forward error correction performance with less computational complexity than bit-interleaved coded modulation schemes. The ability to adapt changing channel conditions is achieved by exploiting the inherent structure of quasi-cyclic LDPC codes.
Two novel packet scheduling algorithms, the basic and modified priority and fairness (BPF and MPF)-based packet scheduling algorithms, are proposed in this paper for adaptive modulation and coding (AMC)-based orthogon...
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Two novel packet scheduling algorithms, the basic and modified priority and fairness (BPF and MPF)-based packet scheduling algorithms, are proposed in this paper for adaptive modulation and coding (AMC)-based orthogonal frequency division multiple access (OFDMA) systems. In the proposed algorithms, various user traffics are transmitted in a sequence determined by their priorities on subchannels while jointly considering fairness among users and subchannels. Simulation results show that the proposed algorithms increase the number of supported users satisfying the same underlying quality of service (QoS) requirements than some existing packet scheduling algorithms in literature.
Coordinated transmission between base stations is one of the techniques under investigation to further improve the system performance of E-UTRA. In general, such a coordination, sometimes also called network MIMO, req...
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Coordinated transmission between base stations is one of the techniques under investigation to further improve the system performance of E-UTRA. In general, such a coordination, sometimes also called network MIMO, requires a large amount of signaling between cells. A relatively simple scheme for cell coordination is macro diversity. In this paper we consider macro diversity for the downlink direction of LTE-Advanced as a means to improve cell edge user throughput. We investigate the frequency-selectivity gains offered by over the air combining for different radio channels at link level. The impact on cell throughput as well as on user throughput for mobiles operated in macro diversity mode and for legacy mobile stations is investigated by means of system level simulations. Additionally, open issues related to network coordination are identified for future work.
To mitigate the effects of time-varying fading, Pilot Symbol Assisted modulation (PSAM) has been introduced, through which the transmitter periodically inserts known symbols or pilots in the data frame. The channel es...
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To mitigate the effects of time-varying fading, Pilot Symbol Assisted modulation (PSAM) has been introduced, through which the transmitter periodically inserts known symbols or pilots in the data frame. The channel estimates obtained from these pilots are then employed in the coherent demodulation of data symbols. A novel PSAM scheme was introduced in that adapts the transmitter's coded modulation strategy to the quality of the channel estimate at the receiver without requiring any channel-feedback from the latter. In our work, we study the performance of this non-feedback adaptive PSAM scheme using clustering techniques. More precisely, instead of using one pilot per data frame, we send a cluster of pilots consecutively in the beginning of every data transmission interval. The performance of this scheme is measured in terms of achievable rates using binary signaling and modeling the fading process as a Gauss-Markov process. We show through numerical computations that our new strategy provides higher achievable rates at certain levels of SNR and fading correlation, and we provide numerical answers to how much training is ¿optimal¿ for the strategy. Finally, we show how the methodology may be extended to high-order Gauss-Markov fading models, with which pilot clustering is expected to yield even higher benefits.
In this paper, we propose an evolved partial response scheme capable of 256-QAM single carrier radio access. Rather than using such high order modulations as 64-QAM or 256-QAM, we employ aggregations of low order modu...
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In this paper, we propose an evolved partial response scheme capable of 256-QAM single carrier radio access. Rather than using such high order modulations as 64-QAM or 256-QAM, we employ aggregations of low order modulation signals whose transmission speeds are beyond the Nyquist rate. To detect these modulation signals, we use a semi-ring structure and reduced state methods in order to exploit the turbo principle, and this makes it possible to achieve high speed processing and low complexity. Simulation results show that, at the same coding and bit rates, the proposed method performs better than do high order modulations over AWGN and multi-path radio channels. Further, by employing opportunistic scheduling transmission, the proposed method is able to achieve improved FER performance. It does this by exploiting a property which turns a severe multipath fading condition into a performance benefit for a channel, making possible a better single carrier radio access scheme.
In this paper, using the equivalent single-input single-out (SISO) model, we derive the exact symbol error rate (SER) and bit error rate (BER) of orthogonal space-time block codes (OSTBCs) with multiple modulations ov...
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In this paper, using the equivalent single-input single-out (SISO) model, we derive the exact symbol error rate (SER) and bit error rate (BER) of orthogonal space-time block codes (OSTBCs) with multiple modulations over flat uncorrelated and correlated Rayleigh fading channels. We provide the impact of antenna correlation on the performance of OSTBCs. The results showed that the symbol error rate decreases while the number of transmit or receiver antennas increases. When the number of receiving antennas is fixed, the performance of OSTBCs is improved with the increasing number of transmitting antennas, but the more the number of transmitting antennas, the less the improvement. With the increase of the correlation coefficient, the performance of coding is decreasing.
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