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


  • 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


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