Towards the performance of ML and the complexity of MMSE: A hybrid approach for multiuser detection

Byonghyo Shim, Jun Won Choi, Insung Kang

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


In this paper, we consider a low-complexity multiuser detection for downlink of high speed packet access (HSPA) of universal mobile telecommunications system (UMTS). Instead of attempting to perform maximum likelihood (ML) detection of all users in multiple cells, which is impractical for battery powered mobile receiver, we utilize interference cancelled chips obtained from iterative linear minimum mean square error (LMMSE) estimation to perform a near ML detection in a reduced dimensional system. As a result, the worst case complexity of the detection process, achieved by the closest lattice point search (CLPS), is bounded to a controllable level irrespective of multipath spans. Furthermore, by exploiting the LMMSE estimate in tightening the hypersphere condition of the CLPS algorithm so called sphere decoding, we achieve significant improvement in search complexity. From simulations on realistic downlink communication scenario in HSPA systems, we show that the proposed method offers substantial performance gain over conventional receiver algorithms with reasonable complexity.

Original languageEnglish
Article number6204012
Pages (from-to)2508-2519
Number of pages12
JournalIEEE Transactions on Wireless Communications
Issue number7
Publication statusPublished - 2012

Bibliographical note

Funding Information:
Manuscript received June 27, 2011; revised February 21, 2012; accepted April 18, 2012. The associate editor coordinating the review of this paper and approving it for publication was Y. J. Zhang. B. Shim is with the School of Information and Communication, Korea University, Seoul, Korea (e-mail: J. Choi and I. Kang are with Qualcomm Inc., CA 92121 USA (e-mail: {junwonc, insungk} This work is supported by the Basic Science Research Program through the National Research Foundation (NRF) funded by the Ministry of Education, Science and Technology (MEST) (No. 2011-0012525) and second Brain Korea 21 project. Digital Object Identifier 10.1109/TWC.2012.051512.111220


  • Babai point
  • Closest lattice point search
  • multiuser detection
  • noncausal path metric
  • sphere decoding

ASJC Scopus subject areas

  • Computer Science Applications
  • Electrical and Electronic Engineering
  • Applied Mathematics


Dive into the research topics of 'Towards the performance of ML and the complexity of MMSE: A hybrid approach for multiuser detection'. Together they form a unique fingerprint.

Cite this