Branislav M. Popovic

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A new general class of polyphase sequences with ideal periodic autocorrelation function is presented. The new class of sequences is based on the application of Zadoff-Chu polyphase sequences of length N = sm2, where s and m are any positive integers. It is shown that the generalized chirp-like sequences of odd length have the optimum crosscorrelation(More)
We present sets of spreading sequences that are specifically designed to suit a belief-propagation multiuser detection structure, recently presented for overloaded system scenarios. On one hand, our sequences are of the low-density type; on the other their distance spectrum properties ensure good performance in AWGN channels. Simulations results for raw and(More)
The paper contains an analysis of the basic criteria for the selection of spreading sequences for the multicarrier CDMA (MC-CDMA) systems with spectrum spreading in the frequency domain. It is shown that the time-domain crosscorrelation function between the spreading sequences is not a proper interference measure for the asynchronous MC-CDMA users.(More)
In this paper, a new construction of optimum sets of zero correlation zone (ZCZ) sequences, derived from generalized chirp-like (GCL) sequences, is presented. A special case with reduced alphabet size is also described. In a set of GCL-ZCZ sequences, the length of the zero correlation zone <i>D</i> has the maximum possible value <i>D</i> = <i>t</i> - 1 for(More)
Cell search is the procedure by which a mobile terminal acquires time and frequency synchronization to the network and detects a cell identity. In this paper, we give a non-hierarchical scheme for OFDM systems, where cell-specific signals are concurrently used for synchronization and cell identification. By using time-domain symmetric signals, the symbol(More)
Achieving higher aggregate data rates for many simultaneous users is considered as a fundamental challenge for the next generation of wireless systems. With low-density spreading (LDS), one could transmit information by overloading, i.e., using more spreading sequences than chips with reasonable implementation complexity. In this paper, we propose an(More)