Multiuser Detection for Turbo-Coded DS/CDMA. (May 2001)Qinghua Li, B.E., South China University of Technology;M.E., Tsinghua University, BeijingCo–Chairs of Advisory Committee: Dr. Costas N. GeorghiadesDr. Xiaodong Wang Multiuser detection and turbo coding are two of the most powerful techniquesfor enhancing the performance of next-generation wideband code-division multiple-...

| An approach to optimal soft decoding for vector quantization over a code-division multiple-access channel is presented. The decoder of the system is soft in the sense that the unquantized outputs of the matched lters are utilized directly for decoding (no decisions are taken), and optimal according to the minimum mean squared error criterion. The derived decoder utilizes a-priori source infor...

In this paper, we consider the application of multiuser detection to the downlink of interference-limited multipleinput multiple-output (MIMO) cellular systems. MIMO systems have been shown to yield a tremendous capacity for a single link with white Gaussian noise. In a cellular environment, there will often be co-channel interference from other cells, which becomes the dominating channel impai...

1 The issue of group-blind multiuser detection in MAC channel among wireless nodes in the environment of multiple networks coexisting and sharing spectrum is addressed under the Framework of coalitional game. We investigate the performance and stability of multiple access channel (MAC) with linear decorrelating multiuser detection under varying SNR, channel gains and coalitional structures, in ...

Direct sequence code division multiple access (DS-CDMA) is a popular wireless technology. This paper presents comparative study between linear multiuser detectors, optimal multiuser detector, and conventional single user matched filter in DS-CDMA system. Analysis and simulations are conducted in synchronous AWGN channel, and Gold sequence is used as the spreading codes. The study shows that opt...

We consider the problem of multiuser detection for DSCDMA in doubly-selective (timeand frequency-selective) channels, and propose a time-varying multiuser detector (TVMUD) to solve this problem. Using a basis expansion model (BEM) to model the doubly-selective channel and the TVMUD, we derive a closed-form expression for the BEM coefficients of the TV-MUD as a function of the BEM coefficients o...

In MIMO receivers, the channel state needs to be estimated for equalization, detection, and for feedback to the transmitter in case of adaptive modulation and coding. Most current iterative [7, 16, 27] and non-iterative [25] schemes in the single-user MIMO case are training-based and rely on the transmission of pilot symbols. Alternatives to pilot-based algorithms are semi-blind schemes which e...

Potential applications of blind channel identification and equalization in data communication systems have recently been explored. For multiuser systems that are irreducible and column-reduced, second-order statistical methods normally can identify channel dynamics up to a unitary mixing matrix. Additional user separation (equalization) can rely on higher order statistics and other prior inform...

We propose entangled (M+1)-mode quantum states as a multiuser quantum channel for continuous-variable communication. Arbitrary quantum states can be sent via this channel simultaneously to M remote and separated locations with equal minimum excess noise in each output mode. For a set of coherent-state inputs, the channel realizes optimal symmetric 1-->M cloning at a distance ("telecloning"). It...

Multiuser multiple-input multiple-output (MIMO) downlink (DL) transmission schemes experience both multiuser interference as well as inter-antenna interference. The singular value decomposition provides an appropriate mean to process channel information and allows us to take the individual user’s channel characteristics into account rather than treating all users channels jointly as in zero-for...