WCDMA Uplink Capacity of Highways Cigar-Shaped Microcells with Incorporated HSUPA Service

The multi-service (voice, data and HSUPA) uplink capacity and the interference statistics of the sectors of the cigar-shaped WCDMA microcell are studied using a model of 5 highway microcells. The two-slope propagation loss model with lognormal shadowing is used in the analysis. It is concluded that the voice and data service are significantly affected by HSUPA users and sector capacity decreases dramatically when one of these users gets connected to a given sector or to one next to it. Also it has been concluded that the capacity decrement is highly sensitive to the location of the HSUPA users. Thus, no more than one HSUPA with a process gain of 16 can be connected to a given base station. In this case, the HSUPA user should interrupt its transmission when it is near to the sector border. No more than one HSUPA user with a process gain of 8 is permitted in a given sector and the sector next to it. When the HSUPA user is at the sector border, its transmission should be disabled.     

A High Bandwidth Power Scalable Sub-Sampling 10-Bit Pipelined ADC With Embedded Sample and Hold

A pipelined ADC architecture for use in sub-sampled systems which is power scalable in relation to its down sampled bandwidth is presented. The ADC uses a technique to eliminate the front-end sample hold, thereby reducing power consumption. The technique allows for a power savings of 20% compared to a previous design. A method to improve the settling behavior of rapid power-on opamps is also presented. Measured results in a 1.8 V 0.18 CMOS process verify the removal of the front-end sample and hold does not cause gross MSB errors for input frequencies higher than 267 MHz. With 50 MS/s, for the SNDR is 51.5 dB, and with 4.55 MS/s for the SNDR is 52.2 dB.     

Cooperative transmission protocol with full diversity and iterative detection

The authors propose a three-node full diversity cooperative protocol, which allows the retransmission of all symbols. By allowing multiple nodes to transmit simultaneously, relaying transmission only consumes limited bandwidth resource. To facilitate the performance analysis of the proposed cooperative protocol, the lower and upper bounds of the outage probability are first developed, and then the high signal-to-noise ratio behaviour is studied. Our analytical results show that the proposed strategy can achieve full diversity. To achieve the performance gain promised by the cooperative diversity, at the relays decode-and-forward strategy is adopted and an iterative soft-interference-cancellation minimum mean-squared error equaliser is developed. The simulation results compare the bit-error-rate performance of the proposed protocol with the non-cooperative scheme and the scheme presented by Azarian et al. (2005).     

New high accuracy CMOS current conveyors

In this paper, a new CMOS CCII⁺ is proposed. The circuit is characterized by high precision in voltage tracking and exhibits very low input resistance. An adaptive voltage offset cancellation methodology is introduced and then applied to the proposed circuit. As a result, a higher accuracy CCII⁺ is presented. For both circuits, the voltage offset cancellation is independent of the input current and voltage. To demonstrate the strength of the proposed architectures, fair comparisons with Liu and Yodprasit CCII realizations are held.     

Apodized chirped fiber Bragg grating for postdispersion compensation in wavelength division multiplexing optical networks

In this paper, a postdispersion compensation unit is proposed leading to a better performance for the optical communication systems. This unit utilizes a chirped fiber Bragg grating (CFBG). For enhanced performance of the CFBG, a proper apodization function is chosen to improve the quality factor (Q‐factor) and the bit error rate (BER) of the system. A 110‐km wavelength division multiplexing (WDM) optical link is investigated. The system performance is evaluated through its Q‐factor, eye diagram, and BER showing best performance when using the Hamming apodization function.     

Analysis of the decoupled uplink downlink technique for varying path loss exponent in multi-tier HetNet

In this paper, the impact of varying path loss exponent (PLE) on user association probability, decoupled uplink coverage probability as well as decoupled uplink average spectral efficiency in downlink uplink decoupled (DUDe) multi-tier heterogeneous networks, is investigated. We investigate the effect of the difference in path loss exponents in both macro and small cell environments over uplink network performance. It is assumed that the mobile user connected to the macro base station experience different path loss exponent as compared to when connected to small base station. It is observed that the difference of path loss exponents in both cases has significant effect on the user association probability, decoupled uplink coverage probability as well as decoupled uplink average spectral efficiency. Moreover, in order to further support key findings and make sound comparison between coupled and DUDe performance in varying PLE environment, generalized analytical expressions for coupled association probabilities, along with coupled uplink coverage probability and coupled uplink average spectral efficiency have been derived. The analytical results evaluated in this paper are compared with the computer simulation and found in good agreement. Our analysis shows that decoupling technique performs suboptimal for cases where the environments around macro and small base stations are different with respect to each other. The work explained in this paper highlights the limitation of applying DUDe technique in realistic conditions where the PLEs of cellular tiers are not exactly equal to one another.

     

POLYBiNN: Binary Inference Engine for Neural Networks using Decision Trees

Journal of Signal Processing Systems - Convolutional Neural Networks (CNNs) and Deep Neural Networks (DNNs) have gained significant popularity in several classification and regression applications....     

Towards SoC Validation Through Prototyping: A Systematic Approach Based on Reconfigurable Platform

Hardware/software covalidation is becoming one of the most critical issues in current System-on-Chip (SoC) design. Nowadays, covalidation is usually performed by cosimulation which is slow and lacks accuracy. The other alternative is to build a hardware prototype specific to the application. However, this alternative is expensive in terms of time, man-power, and cost. As SoCs increase in complexity, validation becomes more and more difficult, time consuming and error prone. Thus, a new approach for covalidation is inescapable. In this paper, we present a novel efficient prototyping approach for complex SoC covalidation. The proposed approach enables systematic prototyping of embedded applications on a reconfigurable platform. The process starts from the RT level model of the application. The application and the reconfigurable platform have to be adapted to obtain the prototype. We decompose the prototyping process into four steps, in order to match the application and the platform. Besides, we propose adapted solutions to deal with constraints typically encountered in existing reconfigurable platforms. The main advantages of this method are: fast and accurate validation, systematic prototyping flow, and large application field. Prototyping of a subset of VDSL using the ARM Integrator platform illustrates the effectiveness of our approach.     

A Threshold-Free LLR-Based Scheme to Minimize the BER for Decode-and-Forward Relaying

In cooperative communications, the problem of error propagation has a detrimental effect on the diversity order of the wireless system. To mitigate such an effect, we present a relaying scheme that is based on the absolute value of the log-likelihood ratio (LLR) of the received message signals at both the relay node and the destination node. The calculated LLR values are then compared to each other and based on the result of the comparison, a decision is made on whether or not to activate the relay node. The proposed scheme does not rely on any threshold, and is thus simple in nature. A closed-form expression is derived for the bit-error-rate (BER) of the proposed scheme. The theoretical developments are validated by simulations. As a means for performance measurement, the proposed scheme is compared to its counterparts and is shown to provide a better BER performance at a much lower complexity. Furthermore, a closed-form expression of the outage probability is also derived.     

Energy efficient scheduling in local area networks

Wireless Networks - In Wireless Local Area Networks (WLAN), portable devices such as notebooks, tabs, and smart phones are powered by batteries with limited energy. With the great increase of using...