Non-data-aided SNR estimation for QPSK modulation in AWGN channel

Signal-to-noise ratio (SNR) estimation is an important parameter that is required in any receiver or communication systems. It can be computed either by a pilot signal data-aided approach in which the transmitted signal would be known to the receiver, or without any knowledge of the transmitted signal, which is a non-data-aided (NDA) estimation approach. In this paper, a NDA SNR estimation algorithm for QPSK signal is proposed. The proposed algorithm modifies the existing Signal-to-Variation Ratio (SVR) SNR estimation algorithm in the aim to reduce its bias and mean square error in case of negative SNR values at low number of samples of it. We first present the existing SVR algorithm and then show the mathematical derivation of the new NDA algorithm. In addition, we compare our algorithm to two baselines estimation methods, namely the M2M4 and SVR algorithms, using different test cases. Those test cases include low SNR values, extremely high SNR values and low number of samples. Results showed that our algorithm had a better performance compared to second and fourth moment estimation (M2M4) and original SVR algorithms in terms of normalized mean square error (NMSE) and bias estimation while keeping almost the same complexity as the original algorithms. 2014 IEEE.Qatar National Research FundScopu

A simple cross correlation switched beam system (XSBS) for angle of arrival estimation

We propose a practical, simple and hardware friendly, yet novel and efficient, angle of arrival (AoA) estimation system. Our intuitive, two-phases cross-correlation-based system requires a switched beam antenna array with a single radio frequency circuitry, which is used to collect an omni-directional reference signal using a single element of the antenna array in the first phase. Our system applies energy detection on the collected reference signal to decide on the presence or absence of a transmitted signal. In the second phase, the system steers the main beam to scan the angular region of interest. The collected signal from each beam angle is cross correlated with the omni-directional reference signal to determine the angle of arrival of the received signal. The combined practicality and high efficiency of our system is demonstrated through performance and complexity comparisons with one of the literature's best performing multiple signal classification (MUSIC) algorithm. Our proposed AoA estimation system has a negligible root mean square error at signal to noise ratio level greater than -16 dB, which is very comparable to MUSIC. 2013 IEEE.Qatar National Research FundScopu

Comparative simulation for physical layer key generation methods

The paper cogitates about a comparative simulation for various distillation, reconciliation, and privacy amplification techniques that are used to generate secure symmetric physical layer keys. Elementary wireless model of two mobile nodes in the presence of a passive eavesdropper is used to perform the comparison process. Important modifications are proposed to some phases' techniques in order to increase the performance of the generation process as a whole. Different metrics were used for comparison in each phase, in the distillation phase, we use the Bit Mismatch Rate (BMR) for different SNR values to compare various extracted random strings of the two intended nodes. On the other hand, the messaging rate and process complexity is exploited to estimate the performance of the compared techniques in both reconciliation and privacy amplification phases. The randomness and entropy properties of the keys are verified using the NIST suite, all the generated keys are 128 bits, it is shown that the success rate of the keys passing the randomness tests depends strongly on the techniques that are used through the three generation phases. 2015 IEEE.Qatar National Research FundScopu

Estimating the number of sources: An efficient maximization approach

Estimating the number of sources received by an antenna array have been well known and investigated since the starting of array signal processing. Accurate estimation of such parameter is critical in many applications that involve prior knowledge of the number of received signals. Information theoretic approaches such as Akaikes information criterion (AIC) and minimum description length (MDL) have been used extensively even though they are complex and show bad performance at some stages. In this paper, a new algorithm for estimating the number of sources is presented. This algorithm exploits the estimated eigenvalues of the auto correlation coefficient matrix rather than the auto covariance matrix, which is conventionally used, to estimate the number of sources. We propose to use either of a two simply estimated decision statistics, which are the moving increment and moving standard deviation as metric to estimate the number of sources. Then process a simple calculation of the increment or standard deviation of eigenvalues to find the number of sources at the location of the maximum value. Results showed that our proposed algorithms have a better performance in comparison to the popular and more computationally expensive AIC and MDL at low SNR values and low number of collected samples. 2015 IEEE.Qatar National Research FundScopu

Mobile wireless sensor networks applied to the survey of water infrastructures

The paper reports our last advances in the realization of mobile wireless sensor networks (WSNs), able to reveal unknown tracks and leakages within underground pipelines used to distribute water. This WSN technology is based on a concept recently proposed by the authors, which makes use of mobile acoustic sensors able to flow within a pipe, transported by the fluid, and equipped with a wireless interface that reports the acquired information to the surface. The paper starts from the early and simplified realization that has been already presented to demonstrate the feasibility of the concept and describes the realization of advanced prototypes, using wireless modules that work in different frequency ranges with specifically designed antennas with the auxiliary possibility to track the position of the device. Ad-hoc solutions have been identified for the construction of the microwave front-end, allowing an improved stability despite the mobility and the rotations. Battery life, compared to application requirements, have been investigated and optimized. Moreover, the technology has been adapted to different operational contexts, making use of different choices of the Physical Layers and various transmission protocol optimizations. At last, results are presented and discussed.Qatar National Research FundScopu