In this paper, a fast dynamic code assignment (FDCA) algorithm is proposed to assign a single Orthogonal Variable Spreading Factor (OVSF)-code for a data rate requirement in next generation wireless access networks. Our algorithm uses the code assignment operation to evaluate the cost for an OVSF-code allocation. The cost is determined by maintaining the data structure that keeps track the numb...

The asymptotic performance of Reed–Solomon (RS)codedM -ary orthogonal signaling with ratio-threshold test (RTT) type demodulation in a Rayleigh-fading channel is considered. We show that the minimum Eb=N0 needed for error-free communication is e ln 2 (2.75 dB) with RTT, and 4.79 (6.8 dB) with hard decisions. The optimum code rate that minimizes the required Eb=N0 is e 1 with RTT and 0.46 with h...

The asymptotic performance of Reed-Solomon coded M-ary orthogonal signaling with ratio-threshold test (RTT) type demodulation in a Rayleigh fading channel is considered. We show that the minimum E b =N 0 needed for error-free communication is e ln 2 (2.75 dB) with RTT, and 4.79 (6.8 dB) with hard decisions. The optimum code rate that minimizes the required E b =N 0 is e ?1 with RTT and 0.46 wit...

DS-CDMA has been recognized as the major candidate for providing high and variable data rates in third generation wireless networks, where multi-code structures and different spreading gains will be employed. In this paper, we address the problem of assignment of variable spreading gain deterministic codes to a set of users, with the objective to maximize down-link system throughput. We propose...

Pairs of words are identified more quickly as coming from different sentences the further apart the words are in the network representation of their native text. How is the distance between the words measured? According to the network connection hypothesis, the distance between 2 words is the length of the network path between the propositions to which they belong, as measured by a process of s...

Blind Synchronization for Multi-rate DS-CDMA Systemsy Zhouyue Pi and Urbashi Mitra Department of Electrical Engineering The Ohio State University, Columbus, OH 43210 e-mail:fpiz,[email protected] Abstract The synchronization problem of multi-rate asynchronous DS-CDMA systems is investigated. Both subspace and non-parametric methods are considered for two types of multi-rate access sch...

Flexible and low-complexity variable rate coding schemes based on rate-compatible con-volutional codes are presented. The codes have a wide range of code rates and are optimized for good performance on both AWGN and Rayleigh fading channels. Furthermore, the application of these codes for rate matching, combined coding and spreading in a DS-CDMA system and hybrid type-II ARQ schemes are demonst...

The blind estimation of mixing channels resulting from frequency selective fading and multipath in a multi-user CDMA system is an important problem in wireless communications. We present a novel frequency-domain approach using second order spectral statistics for recovering the unknown channels. Unlike other methods which are based on timedomain analysis we make no particular assumption about t...

The blind estimation of mixing channels resulting from frequency selective fading and multipath in a multiuser CDMA system is an important problem in wireless communications. We present a novel frequency-domain approach using second order spectral statistics for recovering the unknown channels. Unlike other methods which are based on time-domain analysis we make no particular assumption about t...