Document Type : Original Research Paper


Digital Communications Signal Processing (DCSP) Research Lab., Faculty of Electrical Engineering, Shahid Rajaee Teacher Training University, Tehran, Iran


Uniform linear array (ULA)-based tapped-delay line (TDL) structure has good performance metrics when the signal sources are located at the middle angles. It offers poor performance when the signal sources are close to the array endfire. In this paper, a new approach is proposed which offers higher performance and desired beamforming on TDL structure when the wideband uncorrelated radio sources are close to the array endfire. This new TDL structure is based on Shirvani-Akbari array (SAA). Numerical results of this investigation show that both ULA-based and SAA-based TDL structures have the same performance where the signals of interest located at the middle angles. But, where the signals are close to the array endfire, the SAA-based TDL structure has much higher performance. In order to find a good comparison, the absolute array factor (AF) in center frequency for different angles and three well-known performance metrics, normalized mean square error (NMSE), signal to interference plus noise ratio (SINR) and bit error rate (BER) are evaluated for both ULA-based and SAA-based TDL structures.


[1] S.  Kamboj,  R.  Dahiya,  “Adaptive  antenna  array  for  satellite  communication  systems,”  International  MultiConference  of  Engineers and Computer Scientists, vol. 2, pp. 1491‐1494, 19‐ 21 March 2008. 

[2] P.H.  Lehne,  M.  Pettersen,  “An  overview  of  smart  antenna  technology  for  mobile  communications  systems,”  IEEE  Communications Surveys, vol. 2, no. 4, pp. 2‐13, 1999. 

[3] K.I.  Pedersen,  P.E.  Mogensen,  and  J.  Ramiro‐Moreno,  “Application  and  performance  of  downlink  beamforming  technique in UMTS,”  IEEE Communications Magazine,  vol. 41,  no. 10, pp. 134‐143, Oct. 2003. 

[4] J.H. Winters,  "Smart antenna  techniques and  their application  to wireless  ad‐hoc  networks,"  IEEE  Transactions  on Wireless  Communications, vol. 13, no. 4, pp. 77‐83, August 2006. 

[5] R.D.  Murch,  K.B.  Letaief,  “Antenna  systems  for  broadband  wireless  access,”  IEEE  Transactions  on  Information  Theory,  vol. 40, no. 4, pp. 76‐83, Apr. 2002. 

[6] Y.  Konishi,  “Phased  array  antennas,”  IEICE  Transactions  on  Communications, vol. E86‐B, no. 3, pp. 954‐867, Mar. 2003.

  [7] Ch.  Santhi  Rani,  P.V.  Subbaiah,  and  C.Reddy,  “Smart  antenna  algorithms  for  WCDMA  mobile  communication  systems,”  International  Journal  of  Computer  Science  and  Network  Security (IJCSNS), vol. 8,no. 7, pp. 182‐186, July 2008. 

[8] H.  Li,  T.  Liu,  "Comparison  of  beamforming  techniques  for  WCDMA  Communication  Systems,"  IEEE  Transactions  on  Vehicular Technology, vol. 52, no. 4, pp. 752‐760, July 2003.  

[9] M.  Chryssomallis,  “Smart  antennas,”  IEEE  Antennas  and  Propagation Magazine, vol. 42, pp. 129–136, June 2000. 

[10] L.C. Godara, Smart Antennas, CRC Press, 2004. 

[11] P.  Russer,  “Signal  processing  for  wideband  smart  antenna  array applications,” IEEE Microwave Magazine, vol. 5, no. 1, pp.  57–67, 2004.

  [12] R.A.  Monzingo,  T.W.  Miller,  Introduction  to  Adaptive  Arrays,  SciTech Publishing, 2004. 

[13] S.C.  Chan,  H.H.  Chen,  and  K.L.  Ho,  “Adaptive  beamforming  using  uniform  concentric  circular  arrays  with  frequency  invariant characteristics,” IEEE ISCAS’05, pp. 4321‐ 4324, May  2005. 

[14] S.  Bojanapally, R.S.   Kshetrimayum, “Wideband  antenna  array  beamforming  using  FIR  filter,”  International  Conference  on  Computing  Communication  and  Networking  Technologies  (ICCCNT), pp. 1 – 4, 29‐31 July 2010.

  [15] H.  Duan,  B.  Poh  Ng,  C.  Meng,  S.  See,  and  J.  Fang,  “Broadband  beamforming  using  TDL‐form  IIR  filters,”  IEEE  Transactions  on Signal Processing, vol. 55, no. 3, pp. 990‐1002, March 2007.

[16] W.  Liu,  “Adaptive  broadband  beamforming  with  spatial‐only  information,”  International  Conference  on  Digital  Signal  Processing, pp. 575–578, July 2007. 

[17] W.  Liu,  "Adaptive  wideband  beamforming  with  sensor  delay‐ lines," Elsevier Signal Processing,  vol. 89, no. 5, pp. 876‐ 882,  May 2009. 

[18] N.  Lin,  W.  Liu,  and  R.J.  Langley,  "Performance  analysis  of  an  adaptive  broadband  beamformer  based  on  a  two‐element  linear array with sensor delay‐line processing," Elsevier Signal  Processing, vol. 90, no. 1, pp. 269‐281, January 2010. 

[19] S. Shirvani Moghaddam, N. Solgi, “A comparative study on TDL  and  SDL  structures  for  wideband  antenna  array  beamforming,”  International  Journal  on  Communications  Antenna and Propagation (IRECAP), vol. 1, no. 4, pp. 388‐395,  August 2011. 

[20] S.  Shirvani  Moghaddam,  F.  Akbari,  "A  novel  ULA‐based  geometry for improving AOA estimation," EURASIP Journal on  Advances  in  Signal  Processing,  vol.  2011  (39),  pages  1‐9,  August 2011. 


Journal of Electrical and Computer Engineering Innovations (JECEI) welcomes letters to the editor for the post-publication discussions and corrections which allows debate post publication on its site, through the Letters to Editor. Letters pertaining to manuscript published in JECEI should be sent to the editorial office of JECEI within three months of either online publication or before printed publication, except for critiques of original research. Following points are to be considering before sending the letters (comments) to the editor.

[1] Letters that include statements of statistics, facts, research, or theories should include appropriate references, although more than three are discouraged.

[2] Letters that are personal attacks on an author rather than thoughtful criticism of the author’s ideas will not be considered for publication.

[3] Letters can be no more than 300 words in length.

[4] Letter writers should include a statement at the beginning of the letter stating that it is being submitted either for publication or not.

[5] Anonymous letters will not be considered.

[6] Letter writers must include their city and state of residence or work.

[7] Letters will be edited for clarity and length.