Frequency domain equalization for single-carrier broadband wireless systems
TL;DR: This article surveys frequency domain equalization (FDE) applied to single-carrier (SC) modulation solutions and discusses similarities and differences of SC and OFDM systems and coexistence possibilities, and presents examples of SC-FDE performance capabilities.
Abstract: Broadband wireless access systems deployed in residential and business environments are likely to face hostile radio propagation environments, with multipath delay spread extending over tens or hundreds of bit intervals. Orthogonal frequency-division multiplex (OFDM) is a recognized multicarrier solution to combat the effects of such multipath conditions. This article surveys frequency domain equalization (FDE) applied to single-carrier (SC) modulation solutions. SC radio modems with frequency domain equalization have similar performance, efficiency, and low signal processing complexity advantages as OFDM, and in addition are less sensitive than OFDM to RF impairments such as power amplifier nonlinearities. We discuss similarities and differences of SC and OFDM systems and coexistence possibilities, and present examples of SC-FDE performance capabilities.
Citations
More filters
11 Dec 2006
TL;DR: This paper presents an iterative equalizer for multihop networks with delay diversity, which is tolerant to asynchronous relaying and introduces frequency-domain space-time coding suited for the equalizer.
Abstract: A cooperative diversity requires accurate synchronization for relaying in multihop communications. This paper presents an iterative equalizer for multihop networks with delay diversity, which is tolerant to asynchronous relaying. We introduce frequency-domain space-time coding suited for the equalizer. In addition, we employ cooperative spatial multiplexing to improve the system throughput. We demonstrate that cooperative diversity and multiplexing can offer high spectrum-efficiency even in frequency-selective and poor-scattering channels.
5 citations
Patent•
16 Nov 2005
TL;DR: In this article, the authors used frequency domain equalizer in single carrier wave to resist interference caused by frequency selective fading, including Fourier transform and Fourier inverse transform, technique of spread spectrum code can reduce delay caused from process of serial interference elimination.
Abstract: Treatment for signal of multiple antenna is carried out at frequency domain. Using frequency domain equalizer in single carrier wave resists interferences caused by frequency selective fading. Using serial interference eliminator and parallel interference eliminator eliminate interferences between antennae. Including Fourier transform and Fourier inverse transform, technique of spread spectrum code can reduce time delay caused from process of serial interference elimination. Features are: practical, high effect, low complexity and suitable for actual wide band mobile communication system.
5 citations
TL;DR: The theoretical and simulated performance values for these receivers in terms of their Bit Error Rate (BER) and correlation factor are presented and can help the development of ongoing research involving hybrid analog/digital receivers for 5G and future generations of mobile communications.
Abstract: In the Fifth Generation of telecommunications networks (5G), it is possible to use massive Multiple Input Multiple Output (MIMO) systems, which require efficient receivers capable of reaching good performance values. MIMO systems can also be extended to massive MIMO (mMIMO) systems, while maintaining their, sometimes exceptional, performance. However, we must be aware that this implies an increase in the receiver complexity. Therefore, the use of mMIMO in 5G and future generations of mobile receivers will only be feasible if they use very efficient algorithms, so as to maintain their excellent performance, while coping with increasing and critical user demands. Having this in mind, this paper presents and compares three types of receivers used in MIMO systems, for further use with mMIMO systems, which use Single-Carrier with Frequency-Domain Equalization (SC-FDE), Iterative Block Decision Feedback Equalization (IB-DFE) and Maximum Ratio Combining (MRC) techniques. This paper presents and compares the theoretical and simulated performance values for these receivers in terms of their Bit Error Rate (BER) and correlation factor. While one of the receivers studied in this paper achieves a BER performance nearly matching the Matched Filter Bound (MFB), the other receivers (IB-DFE and MRC) are more than 1 dB away from MFB. The results obtained in this paper can help the development of ongoing research involving hybrid analog/digital receivers for 5G and future generations of mobile communications.
5 citations
01 Mar 2017
TL;DR: Simulation results show that a LTE-like post-OFDM broadband system working with NL PA devices can still coexist with legacy PMR systems with high spectrum and energy efficiencies when proper PA linearisation techniques are applied in combination with effective peak-to-average power ratio reduction methods.
Abstract: The coexistence of broadband systems with currently deployed professional mobile radio (PMR) communication systems like public protection and disaster relief has gained much deserved attention. Recently, it has been shown that a conventional orthogonal frequency division multiplexing (OFDM)-based long-term evolution (LTE) system needs sufficient guard-band or additional filtering in order to coexist in a PMR band, even without considering the radio frequency (RF) impairments of the transmitter. In practice, it is imperative to take into account the RF impairments in radio communication systems, such as the non-linear (NL) nature of a high power amplifier (PA). This paper aims at investigating some enhanced multicarrier techniques allowing the coexistence of narrowband and broadband PMR systems that can support asynchronism, have low latency, and be able to be operated with NL devices. The simulation results show that a LTE-like post-OFDM broadband system working with NL PA devices can still coexist with legacy PMR systems with high spectrum and energy efficiencies when proper PA linearisation techniques are applied in combination with effective peak-to-average power ratio reduction methods. Copyright © 2016 John Wiley & Sons, Ltd.
5 citations
Cites background from "Frequency domain equalization for s..."
...GFDM is flexible to cover CP-OFDM and single-carrier frequency-domain equalization [12] as special cases....
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Patent•
04 Mar 2005TL;DR: In this article, a mobile station consisting of an inputting unit, a generating unit and a transmitting unit is configured to generate a sequence after repetition by performing repetitions for the information sequence input by the input unit for a predetermined number of repetitions.
Abstract: A mobile station, comprising: an inputting unit configured to input an information sequence to be transmitted; a generating unit configured to generate a sequence after repetition by performing repetitions for the information sequence input by the inputting unit for a predetermined number of repetitions; and a transmitting unit configured to transmit to a base station the sequence generated by the generating unit; wherein the generating unit determines the number of repetitions based on a kind of a physical channel.
5 citations
References
More filters
Book•
01 Jan 1986
TL;DR: In this paper, the authors propose a recursive least square adaptive filter (RLF) based on the Kalman filter, which is used as the unifying base for RLS Filters.
Abstract: Background and Overview. 1. Stochastic Processes and Models. 2. Wiener Filters. 3. Linear Prediction. 4. Method of Steepest Descent. 5. Least-Mean-Square Adaptive Filters. 6. Normalized Least-Mean-Square Adaptive Filters. 7. Transform-Domain and Sub-Band Adaptive Filters. 8. Method of Least Squares. 9. Recursive Least-Square Adaptive Filters. 10. Kalman Filters as the Unifying Bases for RLS Filters. 11. Square-Root Adaptive Filters. 12. Order-Recursive Adaptive Filters. 13. Finite-Precision Effects. 14. Tracking of Time-Varying Systems. 15. Adaptive Filters Using Infinite-Duration Impulse Response Structures. 16. Blind Deconvolution. 17. Back-Propagation Learning. Epilogue. Appendix A. Complex Variables. Appendix B. Differentiation with Respect to a Vector. Appendix C. Method of Lagrange Multipliers. Appendix D. Estimation Theory. Appendix E. Eigenanalysis. Appendix F. Rotations and Reflections. Appendix G. Complex Wishart Distribution. Glossary. Abbreviations. Principal Symbols. Bibliography. Index.
16,062 citations
"Frequency domain equalization for s..." refers methods in this paper
...Adaptation can be done with LMS (least mean square), RLS, or least squares minimization (LS) techniques, analogous to adaptation of time domain equalizers [Hay96], [Cla98]....
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...Overlap-save or overlap-add signal processing techniques could also be used to avoid the extra overhead of the cyclic prefix [Fer85], [Hay96]....
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TL;DR: The analysis and simulation of a technique for combating the effects of multipath propagation and cochannel interference on a narrow-band digital mobile channel using the discrete Fourier transform to orthogonally frequency multiplex many narrow subchannels, each signaling at a very low rate, into one high-rate channel is discussed.
Abstract: This paper discusses the analysis and simulation of a technique for combating the effects of multipath propagation and cochannel interference on a narrow-band digital mobile channel. This system uses the discrete Fourier transform to orthogonally frequency multiplex many narrow subchannels, each signaling at a very low rate, into one high-rate channel. When this technique is used with pilot-based correction, the effects of flat Rayleigh fading can be reduced significantly. An improvement in signal-to-interference ratio of 6 dB can be obtained over the bursty Rayleigh channel. In addition, with each subchannel signaling at a low rate, this technique can provide added protection against delay spread. To enhance the behavior of the technique in a heavily frequency-selective environment, interpolated pilots are used. A frequency offset reference scheme is employed for the pilots to improve protection against cochannel interference.
2,627 citations
"Frequency domain equalization for s..." refers background in this paper
...OFDM transmits multiple modulated subcarriers in parallel [ 1 ]....
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...Several variations of orthogonal frequency-division multiplexing (OFDM) have been proposed as effective anti-multipath techniques, primarily because of the favorable trade-off they offer between performance in severe multipath and signal processing complexity [ 1 ]....
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TL;DR: In this contribution the transmission of M-PSK and M-QAM modulated orthogonal frequency division multiplexed (OFDM) signals over an additive white Gaussian noise (AWGN) channel is considered and the degradation of the bit error rate is evaluated.
Abstract: In this contribution the transmission of M-PSK and M-QAM modulated orthogonal frequency division multiplexed (OFDM) signals over an additive white Gaussian noise (AWGN) channel is considered. The degradation of the bit error rate (BER), caused by the presence of carrier frequency offset and carrier phase noise is analytically evaluated. It is shown that for a given BER degradation, the values of the frequency offset and the linewidth of the carrier generator that are allowed for OFDM are orders of magnitude smaller than for single carrier systems carrying the same bit rate. >
1,816 citations
TL;DR: This correspondence describes the construction of complex codes of the form exp i \alpha_k whose discrete circular autocorrelations are zero for all nonzero lags.
Abstract: This correspondence describes the construction of complex codes of the form exp i \alpha_k whose discrete circular autocorrelations are zero for all nonzero lags. There is no restriction on code lengths.
1,624 citations