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
Book Chapter•
31 Jan 2009
TL;DR: An intelligent authentication and key agreement mechanism for e-Hospital applications and a mathematical model for calculating the coverage fraction in wireless sensor networks (WSNs) is addressed.
Abstract: An intelligent authentication and key agreement mechanism for e-Hospital applications is proposed in this book. In addition, a mathematical model for calculating the coverage fraction in wireless sensor networks (WSNs) is addressed.
TL;DR: A channel estimation method for SCOFDM under the framework of compressive sensing (CS) is proposed in this paper, by exploiting the signal.(SP) algorithm to utilize a very small amount of frequency domain pilots embedded in the SC-OFDM block for the exact channel estimation.
Abstract: In current cellular networks base stations (BSs) usually perform independent scheduling without coordinating the resource allocation among different cells. This, however, often leads to high interference levels in cellular networks operating with universal frequency reuse, such as the 3GPP UTRAN Long Term Evolution (LTE). Coordinated scheduling between different BSs may mitigate this problem by taking interference from and to nearby BSs into account in order to avoid high interference situations. For uplink in multiuser major issue to maintain throughput of the system. To solve this problem, a channel estimation method for SCOFDM under the framework of compressive sensing (CS) is proposed in this paper. Firstly, by exploiting the signal.(SP) algorithm to utilize a very small amount of frequency domain pilots embedded in the SC-OFDM block for the exact channel estimation. Moreover, the obtained auxiliary channel information is adopted to reduce the complexity of the classical SP algorithm..
Patent•
28 Jan 2015
TL;DR: In this paper, a radar detector is used with a radio link, the radio link characterized by high duty factor operation of a radio transmitter, and the results of the radar detection are communicated to the transmitter in a way that impacts the transmitter's use of the sensed channel.
Abstract: A radar detector is used with a radio link, the radio link characterized by high duty factor operation of a radio transmitter. The radar detector is located a sufficient distance from the radio transmitter that the radar detector is not overwhelmed by the radio transmission signal in that channel and can detect sufficiently low level radar signals to ascertain potential radio interference at the radar from said radio transmitter. The results of the radar detection are communicated to the transmitter in a way that impacts the transmitter's use of the sensed channel. This communication can occur reactively when a radar detection is achieved (the absence of which indicates no radar has been detected) and/or can be a periodic or event-driven indication that the channel is available for operation (the information expiring if the result is not refreshed).
15 Dec 2014
TL;DR: A new dimension for treating the multipath propagation problems is explored by combining SC/FDE and multiusers transmission technique IFDMA, a broadband technique that is effective and robust in frequency selective fading channels.
Abstract: The Interleaved frequency division multiple access (IFDMA), a multicarrier modulation is treated in this paper as an orthogonal multiple access technique and hence applied to the single carrier with frequency domain equalization (SC/FDE) technique. A new dimension for treating the multipath propagation problems is therefore explored by combining SC/FDE and multiusers transmission technique IFDMA. SC/FDE, a broadband technique is effective and robust in frequency selective fading channels. Further, a kind of constant envelope signals that reduce the impact of power stages non-linearity effects, become obtainable and outperform OFDM technique. SC/FDE proposes block transmission and naturally suits the IFDMA that also implies the block transmission. The combined techniques can apply the equalization in frequency domain which advantageously replaces the time domain equalization.
Cites background from "Frequency domain equalization for s..."
...SC/FDE has been an emerging technique in the last years, its performance is proved to be similar to orthogonal frequency division multiplexing (OFDM) [1] [2]....
[...]
24 Sep 2007
TL;DR: A turbo multi-packet receiver for packet separation in the presence of successive collisions that is suitable for SC-FDE schemes (Single-Carrier with Frequency-Domain Equalization) and the complexity is concentrated in the receiver.
Abstract: In this paper we propose a turbo multi-packet receiver for packet separation in the presence of successive collisions that is suitable for SC-FDE schemes (Single-Carrier with Frequency-Domain Equalization). Our technique allows high throughputs, since the required number of transmissions is equal to the number of packets involved in the collision. Since we consider SC-FDE schemes and the complexity is concentrated in the receiver, this technique particularly appealing for the uplink of broadband wireless systems.
Cites methods from "Frequency domain equalization for s..."
...For this reason, we adopt an SC (Single-Carrier) modulation with FDE (Frequency-Domain Equalization), which is an excellent option for the uplink of severely time-dispersive channels [4], [5]....
[...]
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.
16,062Â 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]....
[...]
...Overlap-save or overlap-add signal processing techniques could also be used to avoid the extra overhead of the cyclic prefix [Fer85], [Hay96]....
[...]
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.
2,627Â citations
"Frequency domain equalization for s..." refers background in this paper
...OFDM transmits multiple modulated subcarriers in parallel [ 1 ]....
[...]
...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 ]....
[...]
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. >
1,816Â 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.
1,624Â citations