Power Reduction of Variable Wordlength OFDM Receiver in Time-Varying Fading Channels by Monitoring Subcarrier SNRs

Determination of wordlength is essential for designing digital circuits because the wordlength affects system performance, hardware size, and power consumption. Variable wordlength methods that a system dynamically and effectively changes the wordlength depending on surrounding environments have been studied for power reduction in wireless systems. The conventional variable wordlength methods induce communication performance degradation when compared with a floating-point representation in time-varying fading channels. This paper discusses rapid wordlength control on packet basis and proposes a new method based on monitoring subcarrier SNRs in an OFDM receiver. The proposed method can estimate signal quality accurately and can decrease the wordlength decision errors. The simulation results have indicated that the proposed method shows better PER performance compared with the conventional methods. key words: wireless communication, variable wordlength, OFDM, digital signal processing circuits

[1]  Yoshikazu Miyanaga,et al.  Use of a Variable Wordlength Technique in an OFDM Receiver to Reduce Energy Dissipation , 2008, IEEE Transactions on Circuits and Systems I: Regular Papers.

[2]  Mats Torkelson,et al.  A new approach to pipeline FFT processor , 1996, Proceedings of International Conference on Parallel Processing.

[3]  Abhijit Chatterjee,et al.  Environment and Process Adaptive Low Power Wireless Baseband Signal Processing Using Dual Real-Time Feedback , 2009, 2009 22nd International Conference on VLSI Design.

[4]  Geoffrey Ye Li,et al.  Cognitive radio networking and communications: an overview , 2011, IEEE Transactions on Vehicular Technology.

[5]  Larsson,et al.  Self-adjusting Bit-precision For Low-power Digital Filters , 1997, Symposium 1997 on VLSI Circuits.

[6]  Alan V. Oppenheim,et al.  Discrete-Time Signal Pro-cessing , 1989 .

[7]  Brian L. Evans,et al.  Wordlength optimization with complexity-and-distortion measure and its application to broadband wireless demodulator design , 2004, 2004 IEEE International Conference on Acoustics, Speech, and Signal Processing.

[8]  Masoud Meghdadi,et al.  Two-Dimensional Multi-Parameter Adaptation of Noise, Linearity, and Power Consumption in Wireless Receivers , 2014, IEEE Transactions on Circuits and Systems I: Regular Papers.

[9]  Andreas Gerstlauer,et al.  Fine grain word length optimization for dynamic precision scaling in DSP systems , 2013, 2013 IFIP/IEEE 21st International Conference on Very Large Scale Integration (VLSI-SoC).

[10]  Margaret Martonosi,et al.  Dynamically exploiting narrow width operands to improve processor power and performance , 1999, Proceedings Fifth International Symposium on High-Performance Computer Architecture.

[11]  Leo Monteban,et al.  WaveLAN®-II: A high-performance wireless LAN for the unlicensed band , 1997, Bell Labs Technical Journal.

[12]  Yoshikazu Miyanaga,et al.  Optimization of multiple wordlength to reduce power dissipation in wireless OFDM systems , 2011 .

[13]  Abhijit Chatterjee,et al.  Real-time use-aware adaptive MIMO RF receiver systems for energy efficiency under BER constraints , 2013, 2013 50th ACM/EDAC/IEEE Design Automation Conference (DAC).

[14]  Rob A. Rutenbar,et al.  Reducing power by optimizing the necessary precision/range of floating-point arithmetic , 2000, IEEE Trans. Very Large Scale Integr. Syst..