Total Weighted Square Correlation Research Articles

Method for Minimizing Total Generalized Squared Correlation of Synchronous DS-CDMA Signature Sequence Sets in Multipath Channels

We characterize the Total Generalized Squared Correlation (TGSC) for a given signature sequence set used in uplink synchronous code division multiple access (S-CDMA) when channel state information is known perfectly at bothtransmitter and receiver. We give a definition of the TGSC based on the eigenvalues of Gram matrix associated to signature sequences set for multipath channels in the presence of the colored noise. Total Squared Correlation (TSC) and Total Weighted Squared Correlation (TWSC) measures are particular cases of TGSC. We present a method for minimizing TGSC (TSC, TWSC) in multipath channels and in the presence of the colored noise. Numerical results for overloaded synchronous CDMA systems are presented in order to support our analysis.

On the Optimal Sequences and Total Weighted Square Correlation of Synchronous CDMA Systems in Multipath Channels

We generalize the total square correlation and the total weighted square correlation (TWSC) for a given signature set used in synchronous code division multiple access (S-CDMA) systems. We define the extended TWSC measure for multipath channels in the presence and the absence of the colored noise. The main results of this paper are the following: 1, the necessary and sufficient conditions of the received Gram matrix to maximize the sum capacity in the presence of multipath; 2, the conditions on the channel such that the received multipath sequences in the presence of the colored noise are Welch bound equality (WBE) sequences; 3, a decentralized method for obtaining generalized WBE sequences that minimize the TWSC in the presence of multipath and colored noise. Using this method, the optimal sequences, which achieve sum capacity for overloaded S-CDMA systems, in the presence of multipath are obtained. Numerical examples that illustrate the mathematical formalism are also included.

Transmitter adaptation algorithm for multicellular synchronous DS-CDMA systems with multipath

A procedure for the design of complex sequence/signature sets for a multicell system under synchronous multipath transmission is presented. The optimization criterion is the total weighted square correlation (TWSC) that incorporates transmission power and channel impulse response values. By solving an inverse eigenvalue problem related to block structured matrices, the bandwidth of initial generalized Welch bound equality signals is preserved in the extended signal space associated to multiple cell system. Numerical results for overloaded uplink multicellular direct-sequence code-division multiple-access (DS-CDMA) systems are presented in order to support our analysis.

Multicell spreading sequence design algorithm for overloaded S-CDMA

An algorithm for the design of the overloaded complex spreading sequence sets on the uplink of multicell synchronous S-CDMA systems is introduced. Assuming that in each cell the number of active users K is greater than the corresponding processing gain N, the total weighted squared correlation (TWSC) criterion is used as a performance measure. The mathematical formalism is supported with selected numerical examples in the multicell context.

Spreading Sequence Design for Multiple Cell Synchronous DS-CDMA Systems under Total Weighted Squared Correlation Criterion

An algorithm for designing spreading sequences for an overloaded multicellular synchronous DS-CDMA system on uplink is introduced. The criterion used to measure the optimality of the design is the total weighted square correlation (TWSC) assuming the channel state information known perfectly at both transmitter and receiver. By using this algorithm it is possible to obtain orthogonal generalized WBE sequences sets for any processing gain. The bandwidth of initial generalized WBE signals of each cell is preserved in the extended signal space associated to multicellular system. Mathematical formalism is illustrated by selected numerical examples.