Conference Paper

Maximum Data Rate Power Allocation for MIMO Spatial Multiplexing Systems with Imperfect CSI

Inst. of Comput. Technol., Chinese Acad. of Sci., Beijing
DOI: 10.1109/VETECS.2009.5073665 Conference: Vehicular Technology Conference, 2009. VTC Spring 2009. IEEE 69th
Source: IEEE Xplore

ABSTRACT In MIMO systems, spatial multiplexing is a powerful technique for increasing channel capacity by transmitting multiple data streams in the same channel simultaneously. Moreover, additional performance can be extracted in the presence of channel state information (CSI) at the transmitter. However, channel estimation error usually exists in practical systems and leads to imperfect CSI. As a result, the system performance is degraded. Fortunately power allocation can mitigate the problem effectively. In this paper, the power allocation problem is investigated in the case of imperfect CSI with accurate system model. A greedy power allocation (GPA) algorithm with adaptive modulation scheme is proposed to maximize the system data rate while satisfying each data stream's bit error rate requirement. Simulation results show that GPA can reduce the effects of imperfect CSI and obtain better performance than other traditional algorithms, e.g. waterfilling and equal power allocation algorithms.

Full-text

Available from: Yao Yuan, Feb 03, 2015
1 Follower
 · 
100 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: A especially favorable multiple-input multiple-output (MIMO)-based concept for future mobile radio systems consists of the application of joint detection (JD) in the uplink and joint transmission (JT) in the downlink. By this, all the computational complex signal processing is shifted to the base station (BS), resulting in low-complexity mobile stations. Both JD and JT require channel knowledge at the BS which, if time-division duplexing is applied, can be obtained by training signal-based channel estimation in the uplink. Unfortunately, channel estimates are never perfect, which leads to performance degradations if these channel estimates, instead of perfect channel knowledge, are used for JD or JT. Especially channel errors due to the time variance of the mobile radio channel are often considered to be a severe problem in the application of MIMO techniques in high-mobility scenarios, which requires closer investigation. In this paper, a novel analysis of the performance degradations of zero-forcing JD and JT due to imperfect channel knowledge is presented. The analysis is based on linear Taylor approximation of the data-estimation error due to imperfect channel knowledge.
    IEEE Transactions on Communications 04/2006; DOI:10.1109/TCOMM.2006.869783 · 1.98 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: By employing spatial multiplexing, multiple-input multiple-output (MIMO) wireless antenna systems provide increases in capacity without the need for additional spectrum or power. Zero-forcing (ZF) detection is a simple and effective technique for retrieving multiple transmitted data streams at the receiver. However the detection requires knowledge of the channel state information (CSI) and in practice accurate CSI may not be available. In this letter, we investigate the effect of channel estimation error on the performance of MIMO ZF receivers in uncorrelated Rayleigh flat fading channels. By modeling the estimation error as independent complex Gaussian random variables, tight approximations for both the post-processing SNR distribution and bit error rate (BER) for MIMO ZF receivers with M-QAM and M-PSK modulated signals are derived in closed-form. Numerical results demonstrate the tightness of our analysis
    IEEE Transactions on Wireless Communications 04/2007; 6(3-6):805 - 810. DOI:10.1109/TWC.2007.05384 · 2.76 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We examine adaptive modulation schemes for flat-fading channels where the data rate, transmit power, and instantaneous BER are varied to maximize spectral efficiency, subject to an average power and BER constraint. Both continuous-rate and discrete-rate adaptation are considered, as well as average and instantaneous BER constraints. We find the general form of power, BER and data rate adaptation that maximizes spectral efficiency for a large class of modulation techniques and fading distributions. The optimal adaptation of these parameters is to increase the power and data rate and decrease the BER as the channel quality improves. Surprisingly, little spectral efficiency is lost when the power or rate is constrained to be constant. Hence, the spectral efficiency of adaptive modulation is relatively insensitive to which degrees of freedom are adapted
    IEEE Transactions on Communications 10/2001; 49(9-49):1561 - 1571. DOI:10.1109/26.950343 · 1.98 Impact Factor