A Rigorous Proof of MIMO Channel Capacity’s Increase with Antenna Number

It is well known that adding more antennas at the transmitter or at the receiver offers larger channel capacity in the multiple-input multiple-output communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receive antennas. The proof is based on the famous capacity formula of Foschini and Gans and uses matrix theory.

Analysis of Lifting and B-Spline DWT Implementations for Implantable Neuroprosthetics

The large amount of data generated by neuroprosthetic devices requires a high communication bandwidth for extra-cranial transmission, critically limiting the number and utility of wireless implantable applications. Discrete wavelet transform (DWT) can provide exceptionally efficient data compression for neural records. Two energy efficient hardware implementations for one dimensional, multi-level, multi-channel DWT have been compared to identify the optimal approach for real time processing within an implanted device. This paper defines area-power minimized hardware implementation of the lifting and B-spline DWT schemes and analyzes their performance tradeoffs for implantable neuroprosthetics. The lifting scheme is shown to be increasingly superior for a larger number of input channels.

A New Routing Metric for Satisfying Both Energy and Delay Constraints in Wireless Sensor Networks

Besides energy constraint, wireless sensor networks should also be able to provide bounded communication delay when they are used to support real-time applications. In this paper, a new routing metric is proposed. It takes into account both energy and delay constraints. It can be used in AODV. By mathematical analysis and simulations, we have shown the efficiency of this new routing metric.

A New Cost Function for Air Quality Modeling

In this paper a new Back-Propagation (BP) algorithm cost function is appropriately studied for the modeling of air pollution time series. The underlying idea is that of modifying the error definition in order to improve the capabilities of this kind of models to forecast episodes of poor air quality. The proposed error definition can be regarded as a generalization of the traditional squared error cost function thanks to the presence of a parameter α which allows to obtain the ordinary BP as a special case when α = 1. A criterion for choosing this parameter is stated based on setting a-priori a maximum level of allowable false alarms. The goodness of the proposed approach is assessed by means of case studies both on synthetic and measured air quality data.

MGFs for Rayleigh Random Variables

Expressions are given for the moment generating functions of the Rayleigh and generalized Rayleigh distributions.

Dynamic Sensor Self-Organization for Distributive Moving Target Tracking

To support distributive tracking of moving targets in a wireless sensor network, sensors that receive signal from the same target must collaborate to facilitate collaborative, distributed target tracking. We present an efficient dynamic sensor self-organizing algorithm that clusters sensors into groups without requiring a centralized control. Extensive simulations are conducted to verify the performance improvement as well as the communication reduction for the proposed methods.

Methods for Compression of Feedback in Adaptive Multi-carrier 4G Schemes

In this paper, several algorithms for compressing the feedback of channel quality information are presented and analyzed. These algorithms are developed for a proposed adaptive modulation scheme for future multi-carrier 4G mobile systems. These strategies compress the feedback data and, used together with opportunistic scheduling, drastically reduce the feedback data rate. Thus the adaptive modulation schemes become more suitable and efficient to be implemented in future mobile systems, increasing data throughput and overall system performance.

A Tool for Unbiased Comparison between Logarithmic and Floating-point Arithmetic

For applications requiring a large dynamic, real numbers may be represented either in floating-point, or in the logarithm number system (LNS). Which system is best for a given application is difficult to know in advance, because the cost and performance of LNS operators depend on the target accuracy in a highly non linear way. Therefore, a comparison of the pros and cons of both number systems in terms of cost, performance and overall accuracy is only relevant on a per-application basis. To make such a comparison possible, two concurrent libraries of parameterized arithmetic operators, targeting recent field-programmable gate arrays, are presented. They are unbiased in the sense that they strive to reflect the state-of-the-art for both number systems. These libraries are freely available at .

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Master Interface for On-chip Hardware Accelerator Burst Communications

We explain a systematic way of interfacing data-flow hardware accelerators (IP) for their integration in a system on chip. We abstract the communication behaviour of the data flow IP so as to provide basis for an interface generator. Then we measure the throughput obtained for different architectures of the interface mechanism by a cycle accurate bit accurate simulation of a SoC integrating a data-flow IP. We show in which configuration the optimal communication scheme can be reached.

Improving Spectral Capacity and Wireless Network Coverage by Cognitive Radio Technology and Relay Nodes in Cellular Systems

Methods to enhance the use of the frequency spectrum by automatical spectrum sensing plus spectrum sharing in a cognitive radio technology context have been presented and discussed in this paper. Ideas to improve the wireless transmission by orthogonal OFDM-based communication and to increase the coverage of cellular systems by future wireless networks, relay channels, relay stations and collaborate radio have been presented as well. A revised hierarchical deployment of the future wireless and wired networks are shortly discussed.

An Operational Conceptual Model for Global Communication Infrastructures

The global communication infrastructure has taken an increased relevance for the future global multimedia village. This global infrastructure has suffered from a mismatch between the conceptual models being used, and the effective operational networks deployed to support it. This mismatch is now affecting the much needed developments to support a global village. This paper presents a novel model for structuring communication networks which closely reflects the visions and needs from an operational network. This model shows a path for protocol evolutions for the global communication infrastructure.

Overall Requirements for Global Information Multimedia Communication Village <Emphasis Type="Italic">10th Strategic Workshop</Emphasis>

The foundations for the definition of the network of the future should be based on a correct user and community characterizations to minimize the fragmentation of the experiences during the global interactions with information communication infrastructures. This paper describes some of the complex objectives and main challenges that telecommunication solution and services have to deal with in order to respect both specific requirements of global user interactions, habits and personalization, and framework requirements about green environments.

Simulation Study of the SIR in Mobile Ad-Hoc Networks

Most studies for mobile ad hoc network (MANET) assume fixed communication range/sensing range (CR/SR) without consideration of signal-to-interference ratio (SIR). In this Letter, we study the impact of SIR with different CR/SR settings by computer simulation. A model with the worst-case scenario, where we allow as many pair of sender/receiver nodes as possible in the simulated area, is developed in this study. Results show that transmission rules based on fixed CR/SR only may not be adequate for use in MANET due to low SIR.

Analysis of Forwarding Mechanisms on Fine-Grain Gradient Sinking Model in WSN

The communication efficiency of large-scale WSNs with high node density is highly related with specific forwarding strategy in complicated wireless environments. Thus, it is the key problem that how to use the characteristic of high-density to select appropriate forwarding nodes to relieve the load imbalance and improve the communication efficiency. In this paper, we first propose a Fine-grain Gradient Sinking (FGS) model and several data forwarding strategies based on this model. Then we give the criteria of communication efficiency and emphatically analyze the communication efficiency of various forwarding strategies. Simulation results show that forwarding strategies under FGS model can achieve higher communication efficiency, and the efficiency can be further elevated by introducing the statistics of packet receive rate during the forwarding process.

An Expression for the Average Quantization Error

The quantization error for MIMO (multiple-input multiple-output) downlink channels is known to be the minimum of independent and identically distributed beta random variables. In this note, an exact expression is derived for the average quantization error. Computational issues relating to its correctness, usage and approximations are discussed.

Isolation of Failing Scan Cells through Convolutional Test Response Compaction

This paper describes a non-recursive fault diagnosis technique for scan-based designs with convolutional test response compaction. The proposed approach allows a time-efficient and accurate identification of failing scan cells using Gauss–Jordan elimination method.

Performance Evaluation of a Multi-band UWB Location and Communication System Based on Modified Gegenbauer Functions

Ultra wide band (UWB) may offer very efficient solutions for various communication and sensing applications. Two approaches have emerged, which meet all the communication requirements: impulse and multi-band systems. The present work is concerned in the second approach. So, we propose to use orthogonal functions called Modified Gegenbauer Functions (MGF) in a multi-band UWB system occupying the 3–6 GHz frequency band. Different scenarios are studied and compared in the scope of a system offering communication and location capabilities for subway trains. In order to evaluate the performance of the proposed system, the bit error rate (BER) values for communication are calculated and analyzed in the presence of multi-user interference, assuming asynchonous users. It is shown that Gegenbauer functions offer the performance required for our multi-band UWB communication and location system.

Design and FPGA-Implementation of a High Performance Timing Recovery Loop for Broadband Communications

Timing recovery in communication systems with linear modulations is usually performed with a non-data-aided feedback loop based on a fractional interpolator timing corrector and the Gardner’s timing error detector. The contribution of this paper is twofold. First, some design rules are given to predict the behaviour of the loop if pipeline is used. Second, it is shown that pipelining can be used to reduce power consumption in a timing feedback loop. A timing recovery loop has been implemented in an FPGA device and power consumption measures indicates that by including 16 extra registers in the loop the power consumption decreases a 63% and the synchronizer can process up to 66.5 MSPS.

Time-frequency hopping sequences with three no hit zones

Based on the idea of no hit zone (NHZ) in frequency hopping (FH) systems, new sequences with three no hit zones (T-NHZ) in time-frequency hopping (TFH) systems are presented. With the T-NHZ in the time- frequency (TF) correlation functions, the proposed T-NHZ sequences can be directly employed in time-frequency hopping code division multiple access (TFH-CDMA) communication systems to reduce or eliminate multipath interference. Simulation results show that T-NHZ sequences can achieve much better bit error performance than the NHZ sequences and the traditional FH sequences.

Reactive ID Assignment for Wireless Sensor Networks

Globally unique ID allocation is usually not applicable in a sensor network due to the massive production of cheap sensor nodes, the limited bandwidth, and the size of the payload. However, locally unique IDs are still necessary for nodes to implement unicast communications to save power consumption. Several solutions have been proposed for locally unique ID assignment in sensor networks. However, they bring much communication overhead, which is not desirable due to the limited power supply in a sensor node. Combined with a directed diffusion communication paradigm, a reactive ID assignment scheme with security mechanisms is proposed in this paper. It defers ID conflict resolution until data communications are initiated and thus saves communication overhead.