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The effect of sample-timing error on the bit-error-rate (BER) performance of the interleave-division multiple access (IDMA) systems are studied in this paper. We construct an asynchronous IDMA system model to investigate the effect of sample-timing error caused by the asynchronous transmission from different user ends (UEs) on the BER performance. The theoretic analysis shows that sample-timing error...
In this work, a system model for RF wireless interconnect has been proposed based on digital on-off keying (OOK) modulated RF transceiver with 2 Gb/s transmission rate and 40 GHz carrier frequency. To evaluate performance of wireless interconnect, the impact of critical non-idealities caused by circuit blocks has been analyzed and simulated in Matlab?? Simulink?? environment. A set of rough circuit...
Code division multiple access (CDMA) utilizes spread spectrum techniques and has been widely deployed in wireless communications. Two major types of spread spectrum multiple access (SSMA) schemes are: i. direct sequence spread spectrum (DSSS) and ii. frequency hopped multiple access (FHMA). The benefits and technical advantages of CDMA could be translated in the optical-CDMA (OCDMA) for faster data...
Communication through intermediate relay node, splits the channel between source and destination into two possibly shorter links, which improves link quality as well as combat with harsh multi-path fading. Close form expressions of average received SNR, outage probability and average bit error rate (BER) have been derived, for the case when communication between source and multi-antenna destination...
The paper derives a more accurate upper bound for BER for M-QAM than is currently used in the literature. This allows a more thorough analysis of the power adaptation to fading conditions for optimization of spectral efficiency. By taking into account the effect of error coding gain on power adaptation, a 7-state FSMC model for the implementation of the adaptive modulation and coding scheme in WiMAX...
HCF controlled channel access (HCCA), defined in the IEEE 802.11e document, provides a sample scheduler to allocate transmission opportunity (TXOP) to QoS-aware stations (QSTAs). Since the calculation of TXOP duration is based on mean data rate, it is efficient for constant bit rate (CBR) traffic. For variable bit rate (VBR) traffic, however, delay bound of some admitted traffic flows may be violated...
It is necessary that the satellite transponder has ability to suppress interferences for reliable communications in real applications, specially military areas. Adaptive interference suppression methods using transform domain approach are presented for an on-board filter bank in this paper. The three kinds of algorithms to compute the threshold level are jointly evaluated with the notch filter or...
We propose a transceiver structure that can effectively improve BER (bit error rate) performance for TR-UWB (transmitted reference-ultra wide band) systems based on impulse radios. Unlike coherent UWB systems that are too complex for practical implementation while having good BER performances, the complexity of the TR-UWB systems is quite low since they transmit data with the corresponding reference...
Bidirectional optical cross connects (BOXCs) using a fiber Bragg gratings (FBGs) and optical circulators (OCs) have been considered for bidirectional WDM ring networks. Theoretical analysis is carried out to evaluate the performance of a bidirectional optical cross connects (BOXCs) in a wave length division multiplexing (WDM) transmission system in the presence of homodyne crosstalk due to fiber Bragg...
The paper evaluates the performance of a CDMA based wireless sensor networks (WSN) in terms of outage probability and BER, considering correlation among interferers in shadowed environment. An appropriate model for the interference power, outage and BER are presented for a single hop communication. Detection probability is also evaluated in shadowed environment. The effects of node density, minimum...
In this paper, we propose a method to enhance the application of importance sampling (IS) technique for efficient simulation of Viterbi decoded terminated convolutional codes. The proposed method exploits the weight enumerators of terminated convolutional codes to enhance the performance of the IS technique known as error event simulation (EES). The essence of the proposed technique is to simulate...
OFDM is one of the most promising techniques for the high speed next generation mobile communication. However, it has a high peak to average power ratio. In this paper, we propose spread spectrum (SS)-OFDM for PAPR reduction. In this method, each subcarrier forms Nyquist pulse the same way to OSSR-OFDM which we proposed in. The results of computer simulation show that our proposal with a large roll-off...
A cognitive radio wireless network is investigated, in which a number of primary users (PUs) transmit in orthogonal frequency bands. There are also a number of secondary users (SUs) in the network, which monitor transmission opportunities in these frequency bands by collaboratively detecting whether each PU is transmitting. Each SU can participate in detecting only one PU's transmission at a time...
We consider the digital fingerprinting problem where colluders apply uniform linear averaging followed by AWGN. For each user, the receiver computes the correlation between the attacked signal and that user's fingerprint, and performs thresholding (focused detection). We model the fingerprinting problem as a multi-user communications problem and develop a detection theoretic framework. Assuming independent...
Compressed sensing deals with the reconstruction of a high-dimensional signal from far fewer linear measurements, where the signal is known to admit a sparse representation in a certain linear space. The asymptotic scaling of the number of measurements needed for reconstruction as the dimension of the signal increases has been studied extensively. This work takes a fundamental perspective on the problem...
This paper describes a dual-band clock and data recovery circuit using a new half-rate linear phase detector. With the proposed sampling scheme, the phase detector produces UP/DN signals with equal pulsewidth and thus eliminates the demand of current scaling in the charge pump. The test chip fabricated by CMOS 0.18 ??m 1P6M process can operate at 2.7 and 1.62 Gbps which satisfies the DisplayPort standard...
In this paper, we analyze the performance of estimating the common support for jointly sparse signals based on their projections onto lower-dimensional space. We formulate support recovery as a multiple-hypothesis testing problem and derive both upper and lower bounds on the probability of error for general measurement matrices, by using Chernoff bound and Fano's inequality, respectively. When applied...
This paper presents an FPGA-based implementation of a tri-mode decoder for decoding the cyclic (4095,3367) Euclidean geometry LDPC code which has minimum distance 65 and no trapping set of size less than 65. The implementation integrates three compatible decoding algorithms in a single decoder. The three decoding algorithms are the one-step majority-logic decoding (OS-MLGD) algorithm and two iterative...
Given the possibility of communication systems failing catastrophically, we investigate limits to communicating over channels that fail at random times. These channels are finite-state semi-Markov channels. We show that communication with arbitrarily small probability of error is not possible. Making use of results in finite block-length channel coding, we determine sequences of block-lengths that...
When rate expectations of users in a wireless network cannot all be satisfied, one choice is to discard some users from the system, in a mechanism called admission control. However, in a data network, users have a certain tolerance to occasional rate outages. In this paper we argue that it may be preferable for users to reduce their rate objectives smoothly, by considering an outage probability tolerance,...
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