Spectrally efficient communication for wireless sensor networks using a cooperative MIMO technique

Abstract

The multi-input multi-output (MIMO) communication framework is adopted for wireless sensor networks by having multiple sensors equipped with single-element antennas cooperate in transmission. A power method-based iterative algorithm is developed that computes the optimal transmit and receive eigen-filters distributively among the sensors while transferring most of the computational burden to the central collector node. Since the proposed algorithm implicitly exploits the channel state information (CSI) both at the receiver and the transmitter, it is expected that the resulting spectral efficiency is higher than what can be achieved by receive CSI-only space-time coding. This intuition is confirmed by employing a variable-rate adaptive modulation scheme for the eigen-transmission and comparing its spectral efficiency with that of orthogonal space time block codes (OSTBCs) at specific target bit error rates. The performance is also evaluated using realistic channel estimation as well as the least mean square (LMS) and recursive least square (RLS) algorithms for iterative eigencoding.

Statistical Analysis of Array Gain for Cooperative MISO Transmitters without CSI

“…As in [2], the analysis covers multiple cooperation nodes at both transmitter and receiver sides, but again results are only provided for 2 x 1 and 2 x 2 Alamouti-based schemes. Another interesting contribution is [4], which analyzes the increase in spectral efficiency that can be achieved with channel state information at the transmitter (CSIT), an assumption that was precluded in previous works based on Alamouti schemes and space-time block codes (STBC). This assumption is also adopted in [5], which analyzes the performance of collaborative beamforming using the theory of random arrays.…”

“…2, that is, at distance D − R from the target destination. In this case, it can be shown that (20) yields the maximum gain G max = N 2 /(1 − α) 4 .…”

Energy efficient wavelet based OFDM for V-BLAST MIMO Wireless Sensor Networks

“…MIMO systems have good spectral efficiency and are known to require less transmission energy than traditional Single Input Single Output (SISO) systems for a given throughput and bit error rate (BER) requirement [1]. However, MIMO systems also have a higher circuit complexity, which consumes energy.…”

Nonlinear Channel Estimation Issues in Cooperative Sensor MIMO

“…The use of multiple single-antenna sensors to form a virtual transmit antenna array has been proposed in [1] [2] and [3]. Typically, each sensor transmits one column of an OSTBC [4], and the resulting spatial/temporal diversity allows tradeoffs between reduced sensor power, error rates and range.…”