Adaptive modulation for maximizing practicable sum capacity in MU-MISO downlink

S. Alireza Banani, Zhuo Chen, Iain Collings, Rodney Vaughan

Research output: Chapter in Book/Report/Conference proceedingConference proceeding contributionpeer-review


This paper addresses adaptive modulation and power allocation for maximizing the practicable sum capacity (sum of the uncoded throughputs of the users) of a multiuser multiple-input single-output MU-MISO) system. Since the optimal solution, dirty paper encoding (DPC), is complicated to implement, we use the simpler linear precoding based on signal- to-leakage-plus-noise ratio (SLNR). For different choices of constellation sizes, the maximum practicable sum capacities and their corresponding optimal power allocations are obtained via individual non-convex optimization. The best constellation sizes for each user are then identified through a search for the highest maximized practicable sum capacity. Simulations demonstrate the significant performance improvement from this approach compared to existing power allocation schemes. Finally, a selection procedure between different constellation sets is presented to obtain the highest practicable sum capacity while maintaining the instantaneous BER of each user below a target value. This approach allows management of the trade-off between the capacity and error performances.

Original languageEnglish
Title of host publication2014 IEEE 80th Vehicular Technology Conference (VTC2014-Fall)
Subtitle of host publicationproceedings
Place of PublicationPiscataway, NJ
PublisherInstitute of Electrical and Electronics Engineers (IEEE)
Number of pages6
ISBN (Electronic)9781479944491
ISBN (Print)9781479944507, 9781479944484
Publication statusPublished - 24 Nov 2014
Externally publishedYes
Event80th IEEE Vehicular Technology Conference, VTC 2014-Fall - Vancouver, Canada
Duration: 14 Sep 201417 Sep 2014


Other80th IEEE Vehicular Technology Conference, VTC 2014-Fall


  • adaptive modulation
  • multi-input multioutput
  • multiuser
  • power allocation
  • practicable capacity
  • sum capacity


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