Shaiful Jahari Hashim

Crosstalk-Aware Multiple Error Detection Scheme Based on Two-Dimensional Parities for Energy Efficient Network on Chip

Achieving reliable operation under the influence of deep-submicrometer noise sources including crosstalk noise at low voltage operation is a major challenge for network on chip links. In this paper, we propose a coding scheme that simultaneously addresses crosstalk effects on signal delay and detects up to seven random errors through wire duplication and simple parity checks calculated over the rows and columns of the two-dimensional data. This high error detection capability enables the reduction of operating voltage on the wire leading to energy saving. The results show that the proposed scheme reduces the energy consumption up to 53% as compared to other schemes at iso-reliability performance despite the increase in the overhead number of wires. In addition, it has small penalty on the network performance, represented by the average latency and comparable codec area overhead to other schemes.

Multiclass Support Vector Machines for Classification of ECG Data with Missing Values

The article presents an experimental study on multiclass Support Vector Machine (SVM) methods over a cardiac arrhythmia dataset that has missing attribute values for electrocardiogram (ECG) diagnostic application. The presence of an incomplete dataset and high data dimensionality can affect the performance of classifiers. Imputation of missing data and discriminant analysis are commonly used as preprocessing techniques in such large datasets. The article proposes experiments to evaluate performance of One-Against-All (OAA) and One-Against-One (OAO) approaches in kernel multiclass SVM for a heartbeat classification problem with imputation and dimension reduction techniques. The results indicate that the OAA approach has superiority over OAO in multiclass SVM for ECG data analysis with missing values.

An overview of spectrum sensing techniques for cognitive LTE and LTE-A radio systems

Advanced communication systems, such as long term evolution (LTE) and LTE-advanced (LTE-A) systems, promise to increase the number of users with high-speed data exchange. However, it leads to spectrum scarcity because of the huge size of data exchange with limited spectrum resources. Cognitive radio (CR) technique is considered the best solution for this spectrum scarcity problem. Spectrum sensing (SS), one of the CR techniques is used to detect the spectrum hole of primary user (PU) without interference with PU. In this paper, several SS approaches for LTE and LTE-A systems are investigated in the CR system. These SS approaches are based on two techniques, namely energy detection and cyclostationary feature detection techniques. The first technique includes four approaches of auto-correlation based advanced energy, time domain detection, Welch periodogram and two-stage model algorithms, while the second technique contains two approaches, namely pilot induced cyclostationary and second order cyclostationary algorithms. According to the analysis, the two-stage model and the second order cyclostationary algorithms are better than the other algorithms because they produce accurate results at the expense of system complexity. Hence, in general a good SS algorithms would require some trade-off between complexity and accuracy.

A low power multiplexer based pass transistor logic full adder

In this paper, a high-speed low-power full adder design using multiplexer based pass transistor logic featuring full-swing output is proposed. The adder is designed and simulated using the industry standard 130 nm CMOS technology, at a supply voltage of 1.2 V. The obtained Power Delay Product (PDP) of its critical path is 29×10-18 J and its power consumption is 2.01μW. The proposed full adder is also capable to function at lower supply voltages of 0.4 V and 0.8 V without significant performance degradation. The proposed adder when cascaded in a 4-bit ripple carry adder configuration, its power, delay and PDP performance are better than the other adders making it suitable for larger arithmetic circuits.

Peak-to-average power ratio reduction based on Cross-Correlation in OFDM systems

Two of the most important techniques of Peak-to-average power ratio (PAPR) reduction in orthogonal frequency division multiplexing (OFDM) systems are Partial Transmit Sequence PAPR (PTS-PAPR) and Cross-Correlation-PTS. This paper investigates a complete analysis on these two techniques providing simulation and discussion of their performance on PAPR reduction and bit error rate (BER). Moreover the comparison of these methods by using Saleh model amplifier in an OFDM system is provided. The results show that PTS-PAPR outperforms the Cross-Correlation-PTS in terms of PAPR performance while Cross-Correlation-PTS method is more efficient in BER reduction.

A new tunnelled EAP based authentication method for WiMAX networks

Despite well-defined and commercially viable security standards for WiMAX networks, vulnerability in current system design and other inherent characteristics expose the network to various types of security attacks. These attacks are commonly related to network access security, authentication of users, validation of data transmission, and confidentiality issues. In order to provide better protection to WiMAX users, several improvements in the security mechanism have been provided. One notable solution is by using a more secure protocol, namely the Privacy Key Management (PKM), which later being revised into PKMv2 (PKM version 2). In this protocol, authentication (as well as mutual authentication) plays an important role since it must be completed in order to establish a secure connection between the network entities. PKMv2 uses either RSA-based or EAP-based authentication modes. While there are variations of authentication modes exist in the literature, some of them prone to man-in-the-middle (MITM) attack and significant overheads. This paper proposes a new method called EAP-TTLS-ISRP which embeds the transmission of security messages in a secure tunnel. This authentication method is proposed for a single EAP based authentication to achieve both user and device authentications between Mobile Station (MS) and Authentication Server (AS) by using strong and fast authentication methods. The proposed method outperforms other methods in the number of messages exchanged and thus it has less overhead cost, it also satisfies the EAP requirement for secure and efficient data exchange, as well as robust to MITM attacks. Automated Validation of Internet Security Protocols and Applications (AVISPA) verification tools are used to verify the security performance of the proposed EAP-TTLS-ISRP method.

Feature level fusion for biometric verification with two-lead ECG signals

Electrocardiogram (ECG) is a new generation of biometric modality which has unique identity properties for human recognition. There are few studies on feature level fusion over short-term ECG signals for extracting non-fiducial features from autocorrelation of ECG windows with an identical length. In this paper, we provide an experimental study on fusion at feature extraction level by using autocorrelation method in conjunction with different dimensionality reduction techniques over vector sets with different window lengths from short and long-term two-lead ECG recordings. The results indicate that the window and recording lengths have significant effects on recognition rates of the fused ECG data sets.

An Adaptive Threshold Feedback Compression Scheme Based on Channel Quality Indicator (CQI) in Long Term Evolution (LTE) System

Channel quality indicator (CQI) feedback in long-term evolution (LTE) system is an essential technique in describing the instantaneous channel state information. The CQI calculations highly depend on the accuracy of the channel estimation process in order to assign appropriate modulation and coding scheme. However, one of the critical issues affecting the LTE system performance is obtaining the CQI for each transmission period which will inevitably cost many resources. Therefore, an appropriate method for reducing CQI feedback overhead along with accurate channel estimation technique is required to manage the allocated resources and obtains significant improvements in system performance. In this paper, an adaptive threshold feedback compression scheme based on CQI scheme is proposed to obtain better system performance in terms of system throughput and error rate in LTE system. This proposed adaptive scheme dynamically adapts its threshold level to the signal to noise ratio variations, thus increasing the throughput and reducing the CQI feedback overhead. Results show that the proposed CQI based adaptive threshold feedback compression scheme enhances the tradeoff between system throughput and block error rate.

Low power GPS baseband receiver design

The versatility of todays travel has increased the need for tracking ones location with the upmost precision. The high power consumption in Global Positioning System (GPS) receiver can cause overheating issues and reduce the battery lifetime, limiting the continuous GPS operation in mobile devices. In this paper, we propose a power management controller utilizing clock-gating technique to reduce the power consumption of the GPS baseband receiver. A power saving of approximately 45% can be achieved through turning off all the unused tracking channels and keeping the number of locked channels to the minimum to get a position. This power management controller design is general and suitable for any multi-channel GPS baseband receiver design.

Digital-Controlled Multimode Multiband Power Amplifier with Multiple Gated Transistor

ABSTRACT Multimode multiband (MMMB) connectivity has become a de facto requirement for smartphones in order to accommodate the various different frequencies, bandwidths, output power, and modulation schemes. In this work, a two-stage single-chip MMMB power amplifier (PA) with multiple gated transistor technique has been designed to obtain dual-mode output power options, with its input matching and intermediate matching networks made tunable to enable switching of the PA output between low-band and high-band frequencies. In the low-band region, the PA offers 195 MHz of operating bandwidth starting from the frequency of 770 up to 965 MHz, covering the long term evolution (LTE) bands 5 and 8, with output saturated power of 27.3 dBm and peak power added efficiency (PAE) of 47.4%. In the high-band region, the PA has 900 MHz bandwidth starting from the frequency of 1.3 up to 2.2 GHz, covering the LTE bands 1, 2, and 3, with output saturated power of 27.9 dBm and peak PAE of 45.3%. The achieved ACPRs are −40 and −42 dBc in the low-band and high-band, respectively, which are well within the LTE linearity specifications. By using a low-cost CMOS process, the proposed MMMB PA has potential applications in the system-on-chip (SoC) integration of wireless transceiver.