Joint Estimation and Decoding of Space-Time Trellis Codes
- PDF / 788,915 Bytes
- 11 Pages / 600 x 792 pts Page_size
- 53 Downloads / 222 Views
Joint Estimation and Decoding of Space-Time Trellis Codes Jianqiu Zhang Department of Electrical and Computer Engineering, State University of New York at Stony Brook, Stony Brook, NY 11794-2350, USA Email: [email protected]
Petar M. Djuri´c Department of Electrical and Computer Engineering, State University of New York at Stony Brook, Stony Brook, NY 11794-2350, USA Email: [email protected] Received 31 May 2001 and in revised form 22 January 2002 We explore the possibility of using an emerging tool in statistical signal processing, sequential importance sampling (SIS), for joint estimation and decoding of space-time trellis codes (STTC). First, we provide background on SIS, and then we discuss its application to space-time trellis code (STTC) systems. It is shown through simulations that SIS is suitable for joint estimation and decoding of STTC with time-varying flat-fading channels when phase ambiguity is avoided. We used a design criterion for STTCs and temporally correlated channels that combats phase ambiguity without pilot signaling. We have shown by simulations that the design is valid. Keywords and phrases: space-time coding, sequential importance sampling, Kalman filtering, phase ambiguity, design criterion.
1. INTRODUCTION Space-time coding (STC) originally introduced by Foschini [1] and further developed by Tarokh et al. in [2] provides a framework for exploiting spatial and temporal diversity to increase data rate in wireless communications. A general introduction of space-time coding can be found in [3]. Among families of space-time codes, we are interested in STTCs because of their many advantages over block STCs as pointed out in [2]. It is generally assumed that STCs will be used in fading environments, and therefore in decoding it is necessary to obtain channel state information (CSI), that is, estimate of the fading coefficients of the channel. In the literature, most of the time it is assumed that CSI becomes available through sending pilot sequences periodically from the transmit to the receive side. When CSI is not available, we have to estimate the channel, and that presents many challenges because the wireless channel may vary with time or frequency or both, and in systems with multiple transmit and receive antennas, many channels need to be estimated. Some design efforts have been directed to the construction of STCs which allow for circumventing channel estimation such as the unitary ST-modulation scheme discussed in [4] or differential spacetime modulation considered in [5]. An interesting Kalman
filter space-time algorithm for joint estimation and decoding of Alamouti’s block ST code [6] was proposed in [7], where Kalman filtering is used for tracking the channel. We have not seen similar work for STTCs. Here we consider the problem of joint channel estimation and decoding of STTCs when no pilot signal is available and the channel is modeled as timevarying flat-fading channel. Because STTCs use complicated modulation schemes, the observation at the receive side may not be a linear
Data Loading...
