Praveen Kumar Dr. Ashok Kumar Jha


Recently, there has been increased interest in moving the RF electronics in base stations from the bottom of the tower to the top, yielding improved power efficiencies and reductions in infrastructural costs. Tower-top systems have faced resistance in the past due to such issues as increased weight, size, and poor potential reliability. However, modern advances in reducing the size and complexity of RF subsystems have made the tower-top model more viable. Tower-top relocation, however, faces many significant engineering challenges. Two such challenges are the calibration of the tower-top array and ensuring adequate reliability. We present a tower-top smart antenna calibration scheme designed for high-reliability tower-top operation. Our calibration scheme is based upon an array of coupled reference elements which sense the array’s output. We outline the theoretical limits of the accuracy of this calibration, using simple feedback-based calibration algorithms, and present their predicted performance based on initial prototyping of a precision coupler circuit for a 2 ×2 array. As the basis for future study a more sophisticated algorithm for array calibration is also presented whose performance improves with array size.

Keywords: Tower-Top Antenna, Array Calibration Scheme, Next Generation Networks.

Full Text:



N. Tyler, B. Allen, and H. Aghvami, “Adaptive antennas: the calibration problem,” IEEE Communications Magazine, vol.42, no. 12, pp. 114–122, 2004.

C. M. Simmonds and M. A. Beach, “Downlink calibration requirements for the TSUNAMI (II) adaptive antenna testbed,” in Proceedings of the 9th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC ’98), vol. 3, pp. 1260–1264, Boston, Mass, USA, September 1998.

K. Sakaguchi, K. Kuroda, J.-I. Takada, and K. Araki, “Comprehensive calibration for MIMO system,” in Proceedings of the 5th International Symposium on Wireless Personal Multimedia Communications (WPMC 3’02), vol. 2, pp. 440–443, Honolulu, Hawaii, USA, October 2002.

C. M. S. See, “Sensor array calibration in the presence of mutual coupling and unknown sensor gains and phases,” Electronics Letters, vol. 30, no. 5, pp. 373–374, 1994.

R. Sorace, “Phased array calibration,” IEEE Transactions on Antennas and Propagation, vol. 49, no. 4, pp. 517–525, 2001.

K. R. Dandekar, L. Hao, and X. Guanghan, “Smart antenna array calibration procedure including amplitude and phase mismatch and mutual coupling effects,” in Proceedings of the IEEE International Conference on Personal Wireless Communications (ICPWC ’00), pp. 293–297, Hyderabad, India, December 2000.

T. Kaiser, “When will smart antennas be ready for the market? Part I,” IEEE Signal Processing Magazine, vol. 22, no. 2, pp. 87–92, 2005.

F. Rayal, “Why have smart antennas not yet gained traction with wireless network operators?” IEEE Antennas and Propagation Magazine, vol. 47, no. 6, pp. 124–126, 2005.

G. Brown, “3G base station design and wireless network economics,” Unstrung Insider, vol. 5, no. 10, pp. 1–30, 2006.

J. D. Fredrick, Y. Wang, and T. Itoh, “A smart antenna receiver array using a single RF channel and digital beamforming,” IEEE Transactions on Microwave Theory and Techniques, vol. 50, no. 12, pp. 3052–3058, 2002.

S. Ishii, A. Hoshikuki, and R. Kohno, “Space hopping scheme under short range Rician multipath fading environment,” in Proceedings of the 52nd Vehicular Technology Conference (VTC ’00), vol. 1, pp. 99–104, Boston, Mass, USA, September 2000.

A. J. Cooper, “‘Fibre/radio’ for the provision of cordless/mobile telephony services in the access network,” Electronics Letters, vol. 26, no. 24, pp. 2054–2056, 1990.

G. Brown, “Open basestation bonanza,” Unstrung Insider, vol. 4, no. 7, pp. 1–20, 2005.

T. Cooper and R. Farrell, “Value-chain engineering of a tower-top cellular base station system,” in Proceedings of the IEEE 65th Vehicular Technology Conference (VTC ’07), pp. 3184– 3188, Dublin, Ireland, April 2007.

T. S. Cooper, R. Farrell, and G. Baldwin, “Array Calibration,” Patent Pending S2006/0482.

T.Cooper,J.McCormack,R.Farrell,andG.Baldwin,“Toward scalable, automated tower-top phased array calibration,” in Proceedings of the IEEE 65th Vehicular Technology Conference (VTC ’07), pp. 362–366, Dublin, Ireland, April 2007.

Analog Devices Datasheet, “400 MSPS 14-Bit DAC 1.8V CMOS Direct Digital Synthesizer,” January 2003.

T. S. Cooper, G. Baldwin, and R. Farrell, “Six-port precision directional coupler,” Electronics Letters, vol. 42, no. 21, pp. 1232–1234, 2006.

Agilent EEsof, Palo Alto, Calif, USA. Advanced Design System, Momentum.

CadSoft Computer, 801 South Federal Hwy., Suite 201, Delray Beach, FL 33483-5185. Eagle.

ECS Circuits, Unit 2, Western Business Park, Oak Close, Dublin 12, Ireland.

Rhode & Schwartz Vertiriebs-GmbH, Muehldorfstrasse 15, 81671 Muenchen, Germany.

J. Hromkovic, Algorithmics for Hard Problems, Springer, Berlin, Germany, 2nd edition, 2004.


  • There are currently no refbacks.