Abstract: In this paper we propose a Particle Swarm heuristic
optimized Multi-Antenna (MA) system. Efficient MA systems
detection is performed using a robust stochastic evolutionary
computation algorithm based on movement and intelligence of
swarms. This iterative particle swarm optimized (PSO) detector
significantly reduces the computational complexity of conventional
Maximum Likelihood (ML) detection technique. The simulation
results achieved with this proposed MA-PSO detection algorithm
show near optimal performance when compared with ML-MA
receiver. The performance of proposed detector is convincingly
better for higher order modulation schemes and large number of
antennas where conventional ML detector becomes non-practical.
Abstract: This paper describes a 2.4 GHz passive switch mixer
and a 5/2.5 GHz voltage-controlled negative Gm oscillator (VCO)
with an inversion-mode MOS varactor. Both circuits are implemented
using a 1P8M 0.13 μm process. The switch mixer has an input
referred 1 dB compression point of -3.89 dBm and a conversion
gain of -0.96 dB when the local oscillator power is +2.5 dBm.
The VCO consumes only 1.75 mW, while drawing 1.45 mA from a
1.2 V supply voltage. In order to reduce the passives size, the VCO
natural oscillation frequency is 5 GHz. A clocked CMOS divideby-
two circuit is used for frequency division and quadrature phase
generation. The VCO has a -109 dBc/Hz phase noise at 1 MHz
frequency offset and a 2.35-2.5 GHz tuning range (after the frequency
division), thus complying with ZigBee requirements.
Abstract: In this paper, a Gaussian multiple input multiple output multiple eavesdropper (MIMOME) channel is considered where a transmitter communicates to a receiver in the presence of an eavesdropper. We present a technique for determining the secrecy capacity of the multiple input multiple output (MIMO) channel under Gaussian noise. We transform the degraded MIMOME channel into multiple single input multiple output (SIMO) Gaussian wire-tap channels and then use scalar approach to convert it into two equivalent multiple input single output (MISO) channels. The secrecy capacity model is then developed for the condition where the channel state information (CSI) for main channel only is known to the transmitter. The results show that the secret communication is possible when the eavesdropper channel noise is greater than a cutoff noise level. The outage probability is also analyzed of secrecy capacity is also analyzed. The effect of fading and outage probability is also analyzed.
Abstract: This paper deals with an adaptive multiuser detector for direct sequence code division multiple-access (DS-CDMA) systems. A modified receiver, precombinig LMMSE is considered under time varying channel environment. Detector updating is performed with two criterions, mean square estimation (MSE) and MOE optimization technique. The adaptive implementation issues of these two schemes are quite different. MSE criterion updates the filter weights by minimizing error between data vector and adaptive vector. MOE criterion together with canonical representation of the detector results in a constrained optimization problem. Even though the canonical representation is very complicated under time varying channels, it is analyzed with assumption of average power profile of multipath replicas of user of interest. The performance of both schemes is studied for practical SNR conditions. Results show that for poor SNR, MSE precombining LMMSE is better than the blind precombining LMMSE but for greater SNR, MOE scheme outperforms with better result.
Abstract: This paper proposes a fast tree join scheme to provide
seamless multicast handover in the mobile networks based on the Fast
Mobile IPv6 (FMIPv6). In the existing FMIPv6-based multicast
handover scheme, the bi-directional tunnelling or the remote
subscription is employed with the packet forwarding from the previous
access router (AR) to the new AR. In general, the remote subscription
approach is preferred to the bi-directional tunnelling one, since in the
remote subscription scheme we can exploit an optimized multicast
path from a multicast source to many mobile receivers. However, in
the remote subscription scheme, if the tree joining operation takes a
long time, the amount of data packets to be forwarded and buffered for
multicast handover will increase, and thus the corresponding buffer
may overflow, which results in severe packet losses. In order to reduce
these costs associated with packet forwarding and buffering, this paper
proposes the fast join to multicast tree, in which the new AR will join
the multicast tree as fast as possible, so that the new multicast data
packets can also arrive at the new AR, by which the packet forwarding
and buffering costs can be reduced. From numerical analysis, it is
shown that the proposed scheme can give better performance than the
existing FMIPv6-based multicast handover schemes in terms of the
multicast packet delivery costs.
Abstract: Performance of a dual maximal ratio combining
receiver has been analyzed for M-ary coherent and non-coherent
modulations over correlated Nakagami-m fading channels with nonidentical
and arbitrary fading parameter. The classical probability
density function (PDF) based approach is used for analysis.
Expressions for outage probability and average symbol error
performance for M-ary coherent and non-coherent modulations have
been obtained. The obtained results are verified against the special
case published results and found to be matching. The effect of the
unequal fading parameters, branch correlation and unequal input
average SNR on the receiver performance has been studied.
Abstract: QoS Routing aims to find paths between senders and
receivers satisfying the QoS requirements of the application which
efficiently using the network resources and underlying routing
algorithm to be able to find low-cost paths that satisfy given QoS
constraints. The problem of finding least-cost routing is known to be
NP-hard or complete and some algorithms have been proposed to
find a near optimal solution. But these heuristics or algorithms either
impose relationships among the link metrics to reduce the complexity
of the problem which may limit the general applicability of the
heuristic, or are too costly in terms of execution time to be applicable
to large networks. In this paper, we concentrate an algorithm that
finds a near-optimal solution fast and we named this algorithm as
optimized Delay Constrained Routing (ODCR), which uses an
adaptive path weight function together with an additional constraint
imposed on the path cost, to restrict search space and hence ODCR
finds near optimal solution in much quicker time.
Abstract: In this paper application of artificial intelligence for
baby and children caring is studied. Then a new idea for injury
prevention and safety announcement is presented by using digital
image processing. The paper presents the structure of the proposed
system. The system determines the possibility of the dangers for
children and babies in yards, gardens and swimming pools or etc. In
the presented idea, multi camera System is used and receiver videos
are processed to find the hazardous areas then the entrance of
children and babies in the determined hazardous areas are analyzed.
In this condition the system does the programmed action capture,
produce alarm or tone or send message.
Abstract: This study aims to identify processes, current
situations, and issues of recycling systems for four home appliances,
namely, air conditioners, television receivers, refrigerators, and
washing machines, among e-wastes in China and Japan for
understanding and comparison of their characteristics. In accordance
with results of a literature search, review of information disclosed
online, and questionnaire survey conducted, conclusions of the study
boil down to:
(1)The results show that in Japan most of the home appliances
mentioned above have been collected through home appliance
recycling tickets, resulting in an issue of “requiring some effort" in
treatment and recycling stages, and most plants have contracted out
their e-waste recycling.
(2)It is found out that advantages of the recycling system in Japan
include easiness to monitor concrete data and thorough
environmental friendliness ensured while its disadvantages include
illegal dumping and export. It becomes apparent that advantages of
the recycling system in China include a high reuse rate, low
treatment cost, and fewer illegal dumping while its disadvantages
include less safe reused products, environmental pollution caused by
e-waste treatment, illegal import, and difficulty in obtaining data.
Abstract: To compress, improve bit error performance and also enhance 2D images, a new scheme, called Iterative Cellular-Turbo System (IC-TS) is introduced. In IC-TS, the original image is partitioned into 2N quantization levels, where N is denoted as bit planes. Then each of the N-bit-plane is coded by Turbo encoder and transmitted over Additive White Gaussian Noise (AWGN) channel. At the receiver side, bit-planes are re-assembled taking into consideration of neighborhood relationship of pixels in 2-D images. Each of the noisy bit-plane values of the image is evaluated iteratively using IC-TS structure, which is composed of equalization block; Iterative Cellular Image Processing Algorithm (ICIPA) and Turbo decoder. In IC-TS, there is an iterative feedback link between ICIPA and Turbo decoder. ICIPA uses mean and standard deviation of estimated values of each pixel neighborhood. It has extra-ordinary satisfactory results of both Bit Error Rate (BER) and image enhancement performance for less than -1 dB Signal-to-Noise Ratio (SNR) values, compared to traditional turbo coding scheme and 2-D filtering, applied separately. Also, compression can be achieved by using IC-TS systems. In compression, less memory storage is used and data rate is increased up to N-1 times by simply choosing any number of bit slices, sacrificing resolution. Hence, it is concluded that IC-TS system will be a compromising approach in 2-D image transmission, recovery of noisy signals and image compression.
Abstract: In this paper, the detection of a fault in the Global Positioning System (GPS) measurement is addressed. The class of faults considered is a bias in the GPS pseudorange measurements. This bias is modeled as an unknown constant. The fault could be the result of a receiver fault or signal fault such as multipath error. A bias bank is constructed based on set of possible fault hypotheses. Initially, there is equal probability of occurrence for any of the biases in the bank. Subsequently, as the measurements are processed, the probability of occurrence for each of the biases is sequentially updated. The fault with a probability approaching unity will be declared as the current fault in the GPS measurement. The residual formed from the GPS and Inertial Measurement Unit (IMU) measurements is used to update the probability of each fault. Results will be presented to show the performance of the presented algorithm.
Abstract: Maximal Ratio Combining (MRC) is considered the most complex combining technique as it requires channel coefficients estimation. It results in the lowest bit error rate (BER) compared to all other combining techniques. However the BER starts to deteriorate as errors are introduced in the channel coefficients estimation. A novel combining technique, termed Generalized Maximal Ratio Combining (GMRC) with a polynomial kernel, yields an identical BER as MRC with perfect channel estimation and a lower BER in the presence of channel estimation errors. We show that GMRC outperforms the optimal MRC scheme in general and we hereinafter introduce it to the scientific community as a new “supraoptimal" algorithm. Since diversity combining is especially effective in small femto- and pico-cells, internet-associated wireless peripheral systems are to benefit most from GMRC. As a result, many spinoff applications can be made to IP-based 4th generation networks.
Abstract: The objective from this paper is to design a solar
thermal engine for space vehicles orbital control and electricity
generation. A computational model is developed for the prediction of
the solar thermal engine performance for different design parameters and conditions in order to enhance the engine efficiency. The engine is divided into two main subsystems. First, the concentrator dish
which receives solar energy from the sun and reflects them to the
cavity receiver. The second one is the cavity receiver which receives
the heat flux reflected from the concentrator and transfers heat to the
fluid passing over. Other subsystems depend on the application required from the engine. For thrust application, a nozzle is
introduced to the system for the fluid to expand and produce thrust.
Hydrogen is preferred as a working fluid in the thruster application.
Results model developed is used to determine the thrust for a
concentrator dish 4 meters in diameter (provides 10 kW of energy),
focusing solar energy to a 10 cm aperture diameter cavity receiver.
The cavity receiver outer length is 50 cm and the internal cavity is 47
cm in length. The suggested design material of the internal cavity is
tungsten to withstand high temperature. The thermal model and
analysis shows that the hydrogen temperature at the plenum reaches
2000oK after about 250 seconds for hot start operation for a flow rate
of 0.1 g/sec.Using solar thermal engine as an electricity generation
device on earth is also discussed. In this case a compressor and
turbine are used to convert the heat gained by the working fluid (air)
into mechanical power. This mechanical power can be converted into
electrical power by using a generator.
Abstract: We investigate efficient spreading codes for transmitter based techniques of code division multiple access (CDMA) systems. The channel is considered to be known at the transmitter which is usual in a time division duplex (TDD) system where the channel is assumed to be the same on uplink and downlink. For such a TDD/CDMA system, both bitwise and blockwise multiuser transmission schemes are taken up where complexity is transferred to the transmitter side so that the receiver has minimum complexity. Different spreading codes are considered at the transmitter to spread the signal efficiently over the entire spectrum. The bit error rate (BER) curves portray the efficiency of the codes in presence of multiple access interference (MAI) as well as inter symbol interference (ISI).
Abstract: This paper may be considered as combination of both pervasive computing and Differential GPS (global positioning satellite) which relates to control automatic traffic signals in such a
way as to pre-empt normal signal operation and permit lifesaving vehicles. Before knowing the arrival of the lifesaving vehicles from
the signal there is a chance of clearing the traffic. Traffic signal
preemption system includes a vehicle equipped with onboard computer system capable of capturing diagnostic information and
estimated location of the lifesaving vehicle using the information provided by GPS receiver connected to the onboard computer system
and transmitting the information-s using a wireless transmitter via a
wireless network. The fleet management system connected to a
wireless receiver is capable of receiving the information transmitted
by the lifesaving vehicle .A computer is also located at the
intersection uses corrected vehicle position, speed & direction
measurements, in conjunction with previously recorded data defining
approach routes to the intersection, to determine the optimum time to
switch a traffic light controller to preemption mode so that lifesaving
vehicles can pass safely. In case when the ambulance need to take a
“U" turn in a heavy traffic area we suggest a solution. Now we are
going to make use of computerized median which uses LINKED
BLOCKS (removable) to solve the above problem.
Abstract: In diversity rich environments, such as in Ultra-
Wideband (UWB) applications, the a priori determination of the
number of strong diversity branches is difficult, because of the considerably large number of diversity paths, which are characterized
by a variety of power delay profiles (PDPs). Several
Rake implementations have been proposed in the past, in order to reduce the number of the estimated and combined paths. To this
aim, we introduce two adaptive Rake receivers, which combine
a subset of the resolvable paths considering simultaneously the
quality of both the total combining output signal-to-noise ratio (SNR) and the individual SNR of each path. These schemes achieve
better adaptation to channel conditions compared to other known receivers, without further increasing the complexity. Their performance
is evaluated in different practical UWB channels, whose models are based on extensive propagation measurements. The
proposed receivers compromise between the power consumption,
complexity and performance gain for the additional paths, resulting in important savings in power and computational resources.
Abstract: Many Wireless Sensor Network (WSN) applications necessitate secure multicast services for the purpose of broadcasting delay sensitive data like video files and live telecast at fixed time-slot. This work provides a novel method to deal with end-to-end delay and drop rate of packets. Opportunistic Routing chooses a link based on the maximum probability of packet delivery ratio. Null Key Generation helps in authenticating packets to the receiver. Markov Decision Process based Adaptive Scheduling algorithm determines the time slot for packet transmission. Both theoretical analysis and simulation results show that the proposed protocol ensures better performance in terms of packet delivery ratio, average end-to-end delay and normalized routing overhead.
Abstract: Scale Time Offset Robust Modulation (STORM) [1]–
[3] is a high bandwidth waveform design that adds time-scale
to embedded reference modulations using only time-delay [4]. In
an environment where each user has a specific delay and scale,
identification of the user with the highest signal power and that
user-s phase is facilitated by the STORM processor. Both of these
parameters are required in an efficient multiuser detection algorithm.
In this paper, the STORM modulation approach is evaluated with
a direct sequence spread quadrature phase shift keying (DS-QPSK)
system. A misconception of the STORM time scale modulation is that
a fine temporal resolution is required at the receiver. STORM will
be applied to a QPSK code division multiaccess (CDMA) system
by modifying the spreading codes. Specifically, the in-phase code
will use a typical spreading code, and the quadrature code will
use a time-delayed and time-scaled version of the in-phase code.
Subsequently, the same temporal resolution in the receiver is required
before and after the application of STORM. In this paper, the bit error
performance of STORM in a synchronous CDMA system is evaluated
and compared to theory, and the bit error performance of STORM
incorporated in a single user WCDMA downlink is presented to
demonstrate the applicability of STORM in a modern communication
system.
Abstract: Multiple-Input-Multiple-Output (MIMO) is one of the most important communication techniques that allow wireless systems to achieve higher data rate. To overcome the practical difficulties in implementing Dirty Paper Coding (DPC), various suboptimal MIMO Broadcast (MIMO-BC) scheduling algorithms are employed which choose the best set of users among all the users. In this paper we discuss such a sub-optimal MIMO-BC scheduling algorithm which employs antenna selection at the receiver side. The channels for the users considered here are not Identical and Independent Distributed (IID) so that users at the receiver side do not get equal opportunity for communication. So we introduce a method of applying weights to channels of the users which are not IID in such a way that each of the users gets equal opportunity for communication. The effect of weights on overall sum-rate achieved by the system has been investigated and presented.
Abstract: Two completely different approaches for a Gigabit
Ethernet compliant stream transmission over 50m of 1mm PMMA SI-POF have been experimentally demonstrated and are compared in this paper. The first solution is based on a commercial RC-LED
transmission and a careful optimization of the physical layer architecture, realized during the POF-PLUS EU Project. The second solution exploits the performance of an edge-emitting laser at the
transmitter side in order to avoid any sort of electrical equalization at the receiver side.