| 1. |
- Alvarado, Alex, 1982, et al.
(författare)
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On the performance of BICM with trivial interleavers in nonfading channels
- 2011
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Ingår i: IEEE International Conference on Communications ICC 2011. - : IEEE. - 1550-3607. - 9781612842332
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Konferensbidrag (refereegranskat)abstract
- Recent results have shown that the performance of bit-interleaved coded modulation (BICM) using convolutional codes in nonfading channels can be greatly improved if the bit-level interleaver takes a trivial form (BICM-T), i.e., if it does not interleave the bits at all. The reported gains reach a few decibels and are obtained using a less complex BICM system. In this paper, we give a formal explanation for these results and show that BICM-T is in fact the combination of a TCM transmitter and a BICM receiver. Analytical bounds that predict the performance of BICM-T are developed and a new type of distance spectrum for the convolutional code is introduced.
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| 2. |
- Chatzidiamantis, N. D., et al.
(författare)
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Diversity combining in hybrid RF/FSO systems with PSK modulation
- 2011
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Ingår i: IEEE International Conference on Communications. - : IEEE. - 1550-3607. - 9781612842332 ; , s. Art. no. 5962684-
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Konferensbidrag (refereegranskat)abstract
- We present a novel architecture for hybrid radio frequency (RF)/ free space optical (FSO) wireless systems without feedback or channel state information (CSI) at the transmitter. Under the assumption that 60 GHz RF and FSO systems support the same data rates, the proposed implementation transmits the same data over both links, using phase shift keying (PSK) as a common modulation scheme, and combines the signals from each individual link at the receiver on a symbol-by-symbol basis. Two popular diversity combining schemes are considered, namely, selection combining (SC) and maximal ratio combining (MRC), while tractable analytical approximations for the bit error rate (BER) are obtained. Investigations over various weather conditions and link distances revealed that the proposed implementation fully exploits the complementary nature of RF and FSO channels, even when one of the two available links fails. Furthermore, the comparison of the combining schemes demonstrates MRC as the optimum combining scheme, offering link distance gains compared to SC.
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| 3. |
- Gholami, Mohammad Reza, 1976, et al.
(författare)
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Hybrid TW-TOA/TDOA Positioning Algorithms for Cooperative Wireless Networks
- 2011
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Ingår i: IEEE International Conference on Communications. - : IEEE. - 1550-3607. - 9781612842332
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Konferensbidrag (refereegranskat)abstract
- The problem of positioning an unknown target is studied for a cooperative wireless sensor network using hybrid two-way time-of-arrival and time-difference-of-arrival measurements. A maximum likelihood estimator (MLE) can be employed to solve the problem. Due to the non-linear nature of the cost function in the MLE, a numerical method, e.g., an iterative search algorithm with a good initial point, should be taken to accurately estimate the target. To avoid drawbacks in a numerical method, we insteadlinearize the measurements and obtain a new two-step estimator that has a closed-form solution in each step.Simulation results confirm that the proposed linear estimator can attain Cram\'er-Rao lower bound for sufficiently high SNR.
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| 4. |
- Tan, Ahmet Serdar, 1982, et al.
(författare)
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An ML-based Detector for Optical Communication in the Presence of Nonlinear Phase Noise
- 2011
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Ingår i: IEEE International Conference on Communications. - : IEEE. - 1550-3607. - 9781612842332 ; , s. Art. no. 5962741-
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Konferensbidrag (refereegranskat)abstract
- We present a closed-form maximum likelihood-based data detection algorithm for long-haul optical channels with dominant nonlinear phase noise induced by self-phase modulation. The closed-form detector is evaluated in terms of symbol error rate as a function of input power, and compared with other sub-optimal detectors as well as a non-parametric detector. We show that the performance of the detector deteriorates for high input power levels, resulting in an optimal operation region. We also provide insights into the behavior of the detector in the highly nonlinear regime.
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| 5. |
- Aulin, Jocelyn, 1964, et al.
(författare)
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Compressive Sensing Aided Determination of WCDMA Constrained Capacity
- 2012
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Ingår i: IEEE International Conference on Communications. - 1550-3607. - 9781457720536 ; , s. 4072-4077
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Konferensbidrag (refereegranskat)abstract
- The continual challenge for Wideband Code Division Multiple Access (WCDMA) communication networks is to provide increasingly higher data rates for more and more users for mobile broadband. Hence, WCDMA single-user and multiple-user capacity results are important references for practical WCDMA networks since they provide limits of performance to which practical systems strive to approach. Analysis and determination of the single and multiple-user WCDMA capacity for dispersive fading channels which include the effects of inter-symbol interference (ISI), inter-channel interference (ICI) and multi-user interference (MUI) (without over-simplifying assumptions to not restrict the applicability of the results) has been a difficult and computationally costly problem. In this paper, we study the WCDMA constrained capacity of a doubly-dispersive wide sense stationary uncorrelated scattering (WSSUS) fading channel, using an equivalent vector channel model of the system with inter-symbol, inter-channel and the multi-user interference due to multipath. To reduce the computational cost of determining the capacity numerically, due to interference, we propose a novel method based on compressive sensing (CS).
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| 6. |
- Aulin, Jocelyn, 1964, et al.
(författare)
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Compressive Sensing for the Capacity of a Rayleigh Fading Channel
- 2011
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Ingår i: 2011 IEEE International Conference on Communications, ICC 2011; Kyoto; Japan; 5 June 2011 through 9 June 2011. - : IEEE. - 1550-3607. - 9781612842325 ; , s. Art. no. 5962506-
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Konferensbidrag (refereegranskat)abstract
- A given objective function, $I(p_X(x))$, is to be maximized over the argument $p_X(x)$, where $p_X(x)$ is a continuous function of $x in R^1$. Rather than optimizing $I(p_X(x))$ over the domain of functions, where the optimal solution $p_X^*(x)$ is non-zero only at a few but unknown discrete points $x in {x_1 , x_2 , ldots , x_S } $, is it possible to solve the optimization problem by optimizing the objective function over S discrete components only? This is the main problem addressed and is solved using compressive sensing (CS) with application to the determination of the capacity of a discrete memoryless Rayleigh-fading channel with peak and average input power constraints. A novel optimization algorithm is developed and applied to a known example. Simulation results, using this novel optimization algorithm, are generated which provides an accurate estimate of the optimizing distribution and the resultant capacity. The significance of this approach is that it can be applied to optimization problems in general and specifically, to communication systems where the domain can be compressed.
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| 7. |
- Chatzinotas, Symeon, et al.
(författare)
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Clustered Multicell Joint Decoding under Cochannel Interference
- 2011
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Ingår i: 2011 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS (ICC). - : IEEE. - 9781612842332 ; , s. 5962542-
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Konferensbidrag (refereegranskat)abstract
- Multicell joint decoding (MJD) has been widely studied during the last decades as a new communication paradigm which can overcome the interference-limited nature of cellular systems. From a practical point of view, a feasible solution is to exploit clusters of cooperating Base Stations (BSs) with intracluster MJD. However, the clusters would still be affected by intercluster cochannel interference. In this paper, the corresponding channel model is established incorporating four impairments, namely additive white Gaussian noise, flat fading, path loss and cochannel interference. The asymptotic capacity limit of this channel is calculated based on an asymptotic free probability approach which exploits the additive and multiplicative free convolution in the R- and Σ-transform domain respectively, as well as properties of the η and Stieltjes transform. Numerical results are utilized to verify the accuracy of the derived closed-form expressions and evaluate the effect of the cochannel interference.
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| 8. |
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| 9. |
- Durisi, Giuseppe, 1977, et al.
(författare)
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On the multiplexing gain of MIMO Microwave backhaul links affected by Phase Noise
- 2013
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Ingår i: IEEE International Conference on Communications. - 1550-3607. - 9781467331227 ; , s. 3209-3214
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Konferensbidrag (refereegranskat)abstract
- We consider a multiple-input multiple-output (MIMO) AWGN channel affected by phase noise. Focusing on the 2 × 2 case, we show that no MIMO multiplexing gain is to be expected when the phase-noise processes at each antenna are independent, memoryless in time, and with uniform marginal distribution over [0,2π] (strong phase noise), and when the transmit signal is isotropically distributed on the real plane. The scenario of independent phase-noise processes across antennas is relevant for microwave backhaul links operating in the 20–40 GHz range.
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| 10. |
- He, Zhongxia Simon, 1984, et al.
(författare)
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A Novel FPGA-based 2.5Gbps D-QPSK Modem for High Capacity Microwave Radios
- 2010
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Ingår i: IEEE International Conference on Communications, 2010.May, Cape Town, South Africa. - 1550-3607. - 9781424464043 ; , s. Art. no. 5501842-
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Konferensbidrag (refereegranskat)abstract
- A novel FPGA-based Differential QPSK modem (modulator and demodulator) is presented for data rates up to 2.5Gbps, in which no DAC or ADC is used. The targeted application is E-Band microwave Point-to-Point radio links in mobile backhaul for LTE and beyond.
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