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Two-dimensional Optical Code Division Multiple Access (2-D OCDMA) has gained great interest among researchers in optical communication systems. This work is aimed to present an alternative way of formulating the spectral/spatial incoherent two-dimensional Extended Enhanced Double Weight (2-D Extended-EDW) code. This code is proposed to suppress the phase induced intensity noise (PIIN) by using multiple...
A 2-Dimensional (2-D) Wavelength/Time (W/T) scheme is proposed for spectral amplitude coding OCDMA network system. The new hybrid codes are utilizing Flexible Cross Correlation (FCC) and Modified Double Weight (MDW) codes which both codes have good correlation properties and capable to suppress multiple access interference (MAI). From the numerical calculation, it has been shown that this new hybrid...
In this paper, a new transmit power allocation (TPA) algorithm is proposed for Vertical Bell Labs Layered Space-Time (V-BLAST) system with channel correlation and estimation error. At the receiver, the minimum mean squared error (MMSE) rule is adopted for signal detection. At the transmitter, adaptive power allocation scheme based on Lagrange multiplier method is presented to allocate appropriate...
In this paper, we propose a new formalism for traffic transmission over optical code-division multiple-access (OCDMA) network architectures capable of mitigating environmental temperature variation effects in the transmission link. Those environmental effects do play an important role in the overall performance of the network. To carry out this analysis, we use unequal priority substreams with unequal...
Super-regenerative receivers (SRR) are known for their ultra-low power (ULP) consumption. However, its wide frequency selectivity seriously degrades performance especially in the presence of interference. An attractive approach to address this problem is by lowering the quench rate of the SRR to the modulation rate. However, this brings in uncertainty due to lack of oversamples and leads to the timing...
In this paper, we propose a novel estimate-and-forward (EF) transmission protocol, and combine it with the essence of compressive sensing (CS) for a network consisting of two correlated sources, one relay and one destination. Compared with the conventional estimate-and-forward (EF) protocol, in our protocol, correlation is exploited in calculating the soft symbols at the relay. Then we transform the...
TCH codes are a class of binary nonlinear cyclic codes that have been used in several systems (e.g. mobile satellite, Ultra-Wideband) for tasks like coding and synchronization. The original generating method of this class of codes restricts the length (or period) of the codewords to the set {2, 4, 16, 256, 65536}. In this paper we use an alternative generation method based on the algebraic properties...
Writing process in hard disk drives (HDD) is affected from nonlinearity. Normally, nonlinearity is not easy to be avoided or removed since it is unexpected and caused by various sources. In this paper, we review a description of a nonlinearity behavior by using a Volterra model, and using a random binary number to generate an input data. The Volterra model can describe both linear and nonlinear parts...
This paper investigates the performance of dualhop multiple antenna amplify-and-forward relaying system of transmit beamforming (TB) and maximum ratio combining considering feedback delay and co-channel interference (CCI) at the relay node. Source-relay and relay-destination channels experience Rayleigh and Rician fading respectively. TB vector is calculated using outdated channel state information...
In this paper, a novel FM-chaos based noncoherent modulation technique is proposed. In this proposed Frequency-Modulated High Efficiency Differential Chaos Shift Keying (FM-HE-DCSK) with selective Orthogonalization scheme, superior qualities of HE-DCSK, like high data rate and bandwidth efficiency are preserved. The proposed scheme is also observed to provide improved BER performance, comparable to...
The performance of transmit beamforming (BF) systems in terms of the spatial correlation coefficient and channel gain variance (CGV) are analyzed over Rayleigh fading channels. We derive bit error rate (BER) of distributed BF (DBF) systems as a function of CGV of distributed channel links. As for clustered BF (CBF), we express its BER as the explicit function of the correlation coefficient. Based...
To improve the performances of a communication link, both in terms of capacity and bit error rate, MIMO technique is a solution which has been widely studied. However, in road or railway tunnels, the waves are guided by the structure and the angular spread of the rays, both at the transmitting side and at the receiving side, is rather small. Nevertheless, improvement of the capacity based on the Shannon...
In this paper, a new noncoherent chaos based communication scheme is presented. System is a hybrid combination of Differential Chaos Shift Keying (DCSK) and Correlation Delay Shift Keying (CDSK) schemes. Here, reference signal block is the sum of outputs from two identical chaos signal generators shifted from each other by a fixed delay, and then each pair of bits is modulated using the same output...
In this paper, we evaluate the influence by a continuous wave (CW) interference on the bit error rate (BER) performance of the spread spectrum (SS) system using a real-valued Huffman sequence under the additive white Gaussian noise (AWGN) environment. The aperiodic correlation function of the sequence has zero sidelobes except at the left and right shift-ends. The system can give the unified communication...
Data hiding schemes using complete complementary codes have been developed for image and audio signals. It has been shown that a high payload and a low bit-error-rate can be achieved by such data hiding strategies because of the ideal auto- and cross-correlation properties of complete complementary codes. The authors have proposed a disaster prevention broadcasting system based on the data hiding...
This paper clarifies the bit error rate (BER) performance of a new multicarrier code division multiple access (MC-CDMA) scheme without the multiple access interference (MAI) and inter carrier interference (ICI) over a very large delay spread channel, which can be characterized by a block coding technique using a set of sequences with a zero correlation zone (ZCZ code) and the minimum mean square error...
Most of the studies on spatial modulation (SM) signal detection assume perfect channel state information (CSI) and ignore the channel's time-spatial correlation. Performance degradation incurs in the presence of imperfect CSI and channel correlations when estimating or predicting channel state based on periodic pilots. Detector structures that take into account both the channel estimation error and...
We propose a semi-blind multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) system, with a precoding aided carrier frequency offset (CFO) estimation approach, and an independent component analysis (ICA) based equalization structure. A number of reference data sequences are carefully designed offline and are superimposed to source data via a non-redundant linear...
A novel narrowband interference (NBI) suppression technique is considered. The traditional code-aided technique, which is proposed to suppress NBI and multiple access interference (MAI) in DS/CDMA networks simultaneously, encounters large computation complexity or performance deterioration when the processing gain is extremely large or small. These problems are solved by the proposed technique. A...
In this paper, we theoretically analyse the influence by intersymbol interference (ISI) on the bit error rate (BER) performance of the spread spectrum (SS) system using a real-valued Huffman sequence whose aperiodic correlation function has zero sidelobes except at the left and right shift-ends, under the quasi-static Rayleigh fading environment. The system can give the unified communication and ranging...
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