Dedicated VLSI Architectures for Adaptive Interference Suppression in Wireless Communication Systems

In this contribution we discuss adaptive signal processing algorithms for interference suppression based on either spatial filtering using base station antenna arrays (→ “smart” antennas) or a special form of transversal filtering (→ linear equalisers for advanced DS-CDMA receivers). It is demonstrated that for reliable operation in non-stationary environments with different levels of interference, such as encountered in mobile radio, RLS-based techniques are inevitable due to their superior transient behaviour. In order to overcome the associated problems of numerical stability and large computational complexity, we propose to employ the QRD-RLS algorithm which solely relies on numerically robust transformations and can be implemented efficiently in VLSI technology based on a network of simple CORDIC arithmetic units which makes extensive use of parallel processing. The hardware implementation of such a 2D systolic array as well as an alternative pipelined linear array capable of real-time operation in high data rate systems (> 2 Mbps) is presented together with bit-true performance assessments for applications involving adaptive antennas. Special attention is given to the interactive design process required to successfully develop advanced algorithms and dedicated hardware architectures for tackling demanding signal processing tasks.

[1]  C. M. Rader,et al.  VLSI systolic arrays for adaptive nulling [radar] , 1996, IEEE Signal Process. Mag..

[2]  Alfred E. Dunlop,et al.  Managing complexity in IC design — Past, present, and future , 1997, Bell Labs Technical Journal.

[3]  Jack E. Volder.  The CORDIC Trigonometric Computing Technique , 1959, IRE Trans. Electron. Comput..

[4]  L. Lucke,et al.  Adaptive CDMA receiver implementation for multipath and multiuser environments , 1996, VLSI Signal Processing, IX.

[5]  Upamanyu Madhow,et al.  MMSE interference suppression for direct-sequence spread-spectrum CDMA , 1994, IEEE Trans. Commun..

[6]  Takeo Ohgane.  Spectral efficiency improvement by base station antenna pattern control for land mobile cellular systems , 1993, Proceedings of GLOBECOM '93. IEEE Global Telecommunications Conference.

[7]  S. Haykin,et al.  Adaptive Filter Theory , 1986 .

[8]  H. M. Ahmed,et al.  A VLSI array CORDIC architecture , 1989, International Conference on Acoustics, Speech, and Signal Processing,.

[9]  H. Samueli,et al.  A digital adaptive beamforming QAM demodulator IC for high bit-rate wireless communications , 1998 .

[10]  Y.H. Hu,et al.  CORDIC-based VLSI architectures for digital signal processing , 1992, IEEE Signal Processing Magazine.

[11]  Branka Vucetic,et al.  Adaptive receiver structures for asynchronous CDMA systems , 1994, IEEE J. Sel. Areas Commun..

[12]  Gary J. Saulnier,et al.  An adaptive correlator receiver for direct-sequence spread-spectrum communication , 1996, IEEE Trans. Commun..

[13]  Babak Daneshrad,et al.  30 Mbps wireless data transmission using an equalized 5-MBaud M-QAM testbed , 1997, Proceedings of ICUPC 97 - 6th International Conference on Universal Personal Communications.

[14]  C. Rader,et al.  VLSI systolic arrays for adaptive nulling , 1996 .

[15]  J. S. Walther,et al.  A unified algorithm for elementary functions , 1899, AFIPS '71 (Spring).

[16]  Thomas Kailath,et al.  Capacity improvement with base-station antenna arrays in cellular CDMA , 1994 .

[17]  Upamanyu Madhow,et al.  Pipelined MMSE equalizers for direct-sequence spread-spectrum CDMA channels , 1996, Proceedings of ICUPC - 5th International Conference on Universal Personal Communications.

[18]  Gerhard Fettweis,et al.  On the interaction between DSP-algorithms and VLSI-architecture , 1990, International Zurich Seminar on Digital Communications, Electronic Circuits and Systems for Communications..

[19]  John Litva,et al.  Digital beamforming in wireless communications , 1996 .

[20]  George V. Tsoulos,et al.  Wireless personal communications for the 21st century: European technological advances in adaptive antennas , 1997 .

[21]  Heinrich Meyr,et al.  Digital communication receivers - synchronization, channel estimation, and signal processing , 1997, Wiley series in telecommunications and signal processing.

[22]  Scott L. Miller.  An adaptive direct-sequence code-division multiple-access receiver for multiuser interference rejection , 1995, IEEE Trans. Commun..

[23]  Gerhard Fettweis.  On Implementing Digital Signal Processing Tasks of Communications Systems in VLSI , 1993 .

[24]  H. Vincent Poor,et al.  Code-aided interference suppression for DS/CDMA communications. I. Interference suppression capability , 1997, IEEE Trans. Commun..

[25]  J. Hindering,et al.  CDMA Mobile Station Modem ASIC , 1992, 1992 Proceedings of the IEEE Custom Integrated Circuits Conference.

[26]  Heinrich Meyr,et al.  Advanced digital receiver principles and technologies for PCS , 1995 .

[27]  H. Vincent Poor.  Adaptive Interference Suppression for Wireless Multiple-Access Communication Systems , 2002 .

[28]  R. Woudsma,et al.  R.E.A.L. DSP: Reconfigurable Embedded DSP Architecture for Low-Power/Low-Cost Telecom Baseband Processing , 2002 .

[29]  Heinrich Meyr,et al.  Efficient Design Flow for Fixed-Point Systems , 2002 .

[30]  Z. Kostic,et al.  Digital signal processors in cellular radio communications , 1997, IEEE Commun. Mag..

[31]  Sivanand Simanapalli,et al.  DSP16000: a high performance, low-power dual-MAC DSP core for communications applications , 1998, Proceedings of the IEEE 1998 Custom Integrated Circuits Conference (Cat. No.98CH36143).

[32]  Dirk Timmermann,et al.  A CMOS floating-point vector-arithmetic unit , 1994, IEEE J. Solid State Circuits.

[33]  N. Seshan.  High VelociTI processing [Texas Instruments VLIW DSP architecture] , 1998 .

[34]  Ramjee Prasad,et al.  Universal wireless personal communications , 1998, Mobile communications series.

[35]  Konstantinos Konstantinides,et al.  VLSI signal processing, IX , 1996 .

[36]  Sergio Verdu,et al.  Multiuser Detection , 1998 .

[37]  L. C. Godara,et al.  Applications Of Antenna Arrays To Mobile Communications, Part I: Performance Improvement, Feasibility, And System Considerations , 1997, Proceedings of the IEEE.

[38]  S. Kung,et al.  VLSI Array processors , 1985, IEEE ASSP Magazine.

[39]  Mansoor Shafi,et al.  Wireless communications in the twenty-first century: a perspective , 1997 .

[40]  B. Haller,et al.  Algorithms and VLSI architectures for RLS-based time reference beamforming in mobile communications , 1998, 1998 International Zurich Seminar on Broadband Communications. Accessing, Transmission, Networking. Proceedings (Cat. No.98TH8277).

[41]  H. T. Kung,et al.  Matrix Triangularization By Systolic Arrays , 1982, Optics & Photonics.

[42]  Keshab K. Parhi,et al.  VLSI digital signal processing systems , 1999 .

[43]  H. Vincent Poor,et al.  Code-aided interference suppression for DS/CDMA communications. II. Parallel blind adaptive implementations , 1997, IEEE Trans. Commun..

[44]  Dirk Timmermann,et al.  A programmable CORDIC chip for digital signal processing applications , 1991 .

[45]  L. Godara.  Application of antenna arrays to mobile communications. II. Beam-forming and direction-of-arrival considerations , 1997, Proc. IEEE.

[46]  B.D. Van Veen,et al.  Beamforming: a versatile approach to spatial filtering , 1988, IEEE ASSP Magazine.

[47]  I. Reed,et al.  Rapid Convergence Rate in Adaptive Arrays , 1974, IEEE Transactions on Aerospace and Electronic Systems.

[48]  Richard D. Gitlin,et al.  The impact of antenna diversity on the capacity of wireless communication systems , 1994, IEEE Trans. Commun..

[49]  R. Baines,et al.  The DSP bottleneck , 1995, IEEE Commun. Mag..

[50]  J. G. McWhirter,et al.  Recursive Least-Squares Minimization Using A Systolic Array , 1983, Optics & Photonics.

[51]  Ning Zhang,et al.  Design of a wideband spread spectrum radio using adaptive multiuser detection , 1998, ISCAS '98. Proceedings of the 1998 IEEE International Symposium on Circuits and Systems (Cat. No.98CH36187).

[52]  Keshab K. Parhi,et al.  Pipelined Cordic based QRD-RLS adaptive filtering using matrix lookahead , 1997, 1997 IEEE Workshop on Signal Processing Systems. SiPS 97 Design and Implementation formerly VLSI Signal Processing.