نتایج جستجو برای: multiple correlation
تعداد نتایج: 1119577 فیلتر نتایج به سال:
In this note, we propose a full-duplex decode-and-forward cooperative diversity scheme based on code division with orthogonal complementary codes. We consider a simple case in which a single user is assisted by a single relay to achieve cooperative diversity. When the cooperation is full-duplex, the operational delay of the relay makes the channel asynchronous and this may cause multiple-access...
A new type of a linear decorrelating receiver, named Pseudo-Decorrelator, for asynchronous code division multiple access systems over a Rayleigh fading multipath channel is presented in this paper. Starting with the analyis of the multiple access components of the decision statistics, the outputs of a bank of matched filters, the (K × 3K) cross-correlation matrix for each bit is obtained. The n...
In this paper, we introduce a novel multiple access scheme based on a combination of a multi-levelled modem and multi-carrier techniques with the use of complete complementary codes. This modulation technique combines a multi-dimensional code division multiple access (CDMA) modem with recent designs of perfectly complete complementary orthogonal codes. The rotational properties of the spreading...
We propose a low cost polymeric optical waveguides-based optical CDMA encoder and decoder modules. The structures of the optical CDMA encoder and decoder modules are presented. The performance of the optical CDMA encoder and decoder modules is simulated using 10-chip binary phase-shift keying (BPSK) coding schemes. The optical CDMA encoder and decoder modules can effectively transmit and recove...
ABSTRACT Support of multiple data services can be accomplished via code division multiple access (CDMA) with a constant chip rate, but variable data rates. We present exact equations for the cross-correlation of codes in a multiple-data rate system, and thus equations for the multiple access interference (MAI) and bit error rate (BER). Previous analysis has found the BER using the mean of the M...
A multiple input multiple output (MIMO) radar is an emerging field which has attracted many researchers recently. In this type of radar, unlike an standard phased array radar, one can choose transmitted probing signals freely to maximize the power around the locations of the targets of interest, or more generally to approximate a given transmit beam-pattern, or to minimize the cross-correlation...
Space-time coding (STC) has been shown to play a key role in the design of MIMO radars with closely spaced antennas. Multiple-input–multiple-output (MIMO) radar is emerging technology for target detection, parameter identification, and target classification due to diversity of waveform and perspective. First, it turns out that a joint waveform optimization problem can be decoupled into a set of...
This paper investigates the problem of spreading sequence and receiver code synchronization techniques for satellite based CDMA communications systems. The performance of CDMA system depends on the autocorrelation and cross-correlation properties of the used spreading sequences. In this paper we propose the uses of chaotic Lu system to generate binary sequences for spreading codes in a direct s...
Modern communication systems extensively use Code Division Multiple Access (CDMA) technology that associates one unique code to each user. Therefore the generation of these spreading codes has drawn considerable attention amongst the researchers with a fundamental requirement of having as much distinct members as possible along with a constraint of minimizing the inter-code correlation. Since t...
Three novel classes of optical orthogonal codes (OOCs) based on combinatorial designs are proposed. They are applicable to both synchronous and asynchronous incoherent optical code-division multiple access (OCDMA) and compatible with spectral-amplitude-coding (SAC), fast frequency hopping, and time-spreading schemes. Simplicity of construction, larger codeword families, and larger flexibility i...
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