Relaxing RF component requirements in a Weaver architecture by learning and adapting to the environment

This paper presents an architecture that utilizes spectrum sensing with a Weaver architecture receiver to ease the requirements on the RF front-end components. With the ability to sense the environment, large interferers that overwhelm small desired signals can be avoided. The learning and adapting capabilities are enabled by means of a flexible receiver architecture with variable local oscillators (LOs) and tunable bandpass filters. Avoiding large interferers can reduce image rejection (IR) requirements for a given performance level and results in greater tolerance for low-Q filters and receiver mismatches. The design approach is applied to an IEEE 802.11a receiver and has shown significant performance improvements compared to conventional approaches despite an 18 dB lower image rejection

[1]  Behzad Razavi,et al.  Design considerations for direct-conversion receivers , 1997 .

[2]  H. Samavati,et al.  5-GHz CMOS wireless LANs , 2002 .

[3]  B. Razavi,et al.  A 2 GHz CMOS image-reject receiver with sign-sign LMS calibration , 2001, 2001 IEEE International Solid-State Circuits Conference. Digest of Technical Papers. ISSCC (Cat. No.01CH37177).

[4]  Mourad N. El-Gamal,et al.  RF CMOS fully-integrated heterodyne front-end receivers design technique for 5 GHz applications , 2004, 2004 IEEE International Symposium on Circuits and Systems (IEEE Cat. No.04CH37512).

[5]  Donald K. Weaver,et al.  A Third Method of Generation and Detection of Single-Sideband Signals , 1956, Proceedings of the IRE.

[6]  M.A.I. Elmala,et al.  Calibration of phase and gain mismatches in Weaver image-reject receiver , 2004, IEEE Journal of Solid-State Circuits.

[7]  James C. Yee,et al.  Understanding wirele ss LAN performance trade-offs , 2002 .