Spectral Efficiency and Energy Efficiency Optimization via Mode Selection for Spatial Modulation in MIMO Systems

Spectral Efficiency and Energy Efficiency Optimization via Mode Selection for Spatial Modulation in MIMO Systems



In this work we consider the multiple-inputmultiple-output system employing spatial modulation based transmission in Rayleigh fading channels with known slow varying large-scale fading loss and channel correlations. Observing the system performance is affected by transmission mechanisms and configurations, we propose a framework enabling the selection of the transmission mode for the optimal spectral efficiency (SE) or energy efficiency (EE) while conforming to transmission and error rate requirements with low complexity. In the framework, a closed-form error rate approximation is proposed. It renders the formulated SE and EE-based selection problems solvable via naive exhaustive search method. Besides, we propose to reduce the complexity via using look-up tables. Computer simulations are provided to evaluate the framework.


  • To provide good trade-offs between SE and EE with different numbers of active RF chains, the link adaptive design involving different variants can provide benefits to the systems.
  • To select the best mode from via using the large-scale fading loss and channel correlations.
  • By the result of mode selection, the information bits are converted to the SM-based signal for transmission.


Spatial modulation (SM) based transmission schemes in multiple-input multiple-output (MIMO) systems utilize both the signal and spatial constellations, i.e., both the conventional amplitude and phase modulation (APM) and the antenna indices, to convey information bits The distinct feature of SM-based MIMO enhances the utilization of spatial degrees of freedom (DoFs) with limited number of radio frequency(RF) chains, and renders the SM-based MIMO transceiver lower complexity and potentially higher energy efficiency (EE)as compared to the conventional MIMO.To improve the SM-based MIMO, adaptive designs have been investigated. Here we consider the link adaptive design in whch the system adaptively adopts the most suitable transmission scheme and configuration.


  1. Stavridis, S. Sinanovic, M. Di Renzo, and H. Haas, ”Energy evaluation of spatial modulation at a multi-antenna base station,” in Proc. IEEE VTC-fall, Sept. 2013.

Error rate analysis for typical SM-MIMO in different fading channels,

  1. Bouida1, A. Ghrayeb1, and K. A. Qaraqe, ”Adaptive spatial modulation for spectrally-efficient MIMO systems,” in Proc. IEEE WCNC,Apr. 2014.

Maximize spectral efficiency (SE) with given symbol/bit error rate (SER/BER), were proposed via adapting modulation orders. As considering energy efficiency (EE)maximization, adaptive modulation designs in were proposed without involving circuit power consumption


We propose the framework for selecting thebest transmission mode according to the large-scale fadingloss and spatial correlations in Rayleigh fading channels. Our goal is to pursue the optimization of two fundamental performance metrics: SE and EE. The framework considers SM-based schemes with different transmission rates, spacesignalconstellations, numbers of activated antennas, and withouttransmit diversity design. We first derive the simplifiedclosed-form approximation of the SER/BER applicable fordifferent modes. Then given a pre-determined candidate setof transmission modes, we propose the SE and EE basedselection optimization problems for selecting the mode withthe best SE and EE, respectively. Both optimization problemsare subject to certain error rate, transmission rate, and powerconstraints. By linking the error rate requirement to the transmitpower via the closed-form approximation, the proposed SEand EE optimization problems can be easily solvable by naïve exhaustive search with low complexity. Furthermore, sincethe costly metric computation of the closed-form expressioncan be replaced by the inexpensive table look-up operation,the complexity of the framework can be further reduced.



In this work, we consider the point-to-point MIMO systemequipped with Nt transmit antennas, Nr receive antennas, andseveral RF chains capable of being switched on/off. We adoptSM-based MIMO to convey information bits, and considerthe large-scale fading loss and channel spatial correlationsperfectly known at the transmitter. Given a pre-defined transmissionmode set  with size M, our goal is to select the bestmode from  via using the large-scale fading loss and channelcorrelations. By the result of mode selection, the informationbits are converted to the SM-based signal for transmission. Thereceiver employing the maximum likelihood (ML) detector is then adopted for detection


  • Replaces the error rate constraint with elegant closed-form expression, is the key to the framework
  • It is practical with the low complexity and by using merely the slowly varying channel statistics.



  • System : Pentium Dual Core.
  • Hard Disk : 120 GB.
  • Monitor : 15’’ LED
  • Input Devices : Keyboard, Mouse
  • Ram : 1GB


  • Operating system : Windows 7.
  • Coding Language : MATLAB
  • Tool : MATLAB R2013A


Ming-Chun Lee and Wei-Ho Chung, Member, IEEE, “Spectral Efficiency and Energy EfficiencyOptimization via Mode Selection for SpatialModulation in MIMO Systems”, IEEE Transactions on Vehicular Technology, 2017.


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