CDMA

In modern communication systems, spread spectrum is playing an increasingly important role day by day due to its inherent advantages like noise immunity and also due its practical applications like mobile communications in CDMA. Our project is in accordance with this increasingly important communication technology. This project aims to Generate Gold Code sequence and modulate a message signal to produce a corresponding spreaded baseband modulated signal which is actually used in much higher proportions for transmission of voice and data signals in technologies like CDMA. The project also incorporates a receiver unit which demodulates the entire received signal with the assistance of the same gold code to generate the original message signal. An addition to this primary aim of our project is to study the cross correlation of two Gold Codes sequences and two Pseudo Noise sequences to ascertain which is a better tool for modulating the given message signal in terms of better noise immunity and security with the help of graphs using the MATLAB programming language.

Wavelets have been favorably applied in almost all aspects of digital wireless communication systems including data compression, source and channel coding, signal denoising, channel modeling and design of transceivers. The main property of wavelets in these applications is in their flexibility and ability to characterize signals accurately. In this paper recent trends and developments in the use of wavelets in wireless communications are reviewed. Major applications of wavelets in wireless channel modeling, interference mitigation, denoising, OFDM modulation, multiple access, Ultra Wideband communications, cognitive radio and wireless networks are surveyed. The confluence of information and communication technologies and the possibility of ubiquitous connectivity have posed a challenge to developing technologies and architectures capable of handling large volumes of data under severe resource constraints such as power and bandwidth. Wavelets are uniquely qualified to address this challenge. The flexibility and adaptation provided by wavelets have made wavelet technology a strong candidate for future wireless communication.

Energy consumption is one of the important challenges in WSNs deployment and applications. This is because power of WSNs is limited by battery which is difficult if not impossible to replace or recharge in some manner in the sensor nodes. Power consumption can be controlled in WSNs in more than one layer. In this thesis, power efficiency problems and techniques of enlarging battery life using WSNs physical layer are investigated in the second layer MAC sub-layer. The latter has been achieved using the multiple access techniques, TDMA and CDMA.
Initially, the research attempt to divide the WSN nodes into clusters such that at any time only one specific cluster will operate and the remaining cluster sill be switched off to reduce the power consumption. Each cluster consists of several nodes and one sub-station (SS), the total number of nodes equal to 128 nodes at each case of cluster, all the nodes in one cluster send its data to this (SS) and this (SS) forwards this data to main station (MS). Furthermore, the link between nodes, SS, and MS is controlled and scheduled such that cluster and node switched to active or sleep. Four systems with multi-types of multiple access are proposed and tested with each case of clustering have been adopted. These systems are classified according to the way multiple access provided in the link: TDMA-TDMA-OFDM system, CDMA-CDMA system, CDMA-TDMA-OFDM system, and TDMA-OFDM-TDMA-OFDM system. These systems have been simulated and investigated. By comparing the results of each system with different case of cluster, it has been found that the less consumed powers achieved with 8 clusters of 16 nodes/cluster case. The results also show that the best performance is achieved with CDMA-CDMA system with 8 clusters of 16 nodes/cluster case.
Extra power consumption reduction has been achieved in this research via the application of convolutional coding and interleaving with four proposed systems. It has been found that convolutional code makes better performances and less error rates with different ratio in the proposed system. Furthermore, more enhancement has been achieved by using convolutional code with interleaving to all system except CDMA-CDMA system which gives results similar to the results of convolutional code only. By comparing the results of the proposed system with each other after enhancement, the results show that the CDMA-CDMA system is still has the less error bit ratio and the best performance and achieves the most power consumption reduction.

The development of technological capability (TC) is critical for manufacturing firms in high-tech industries. Stages of development of industrial technology in a developing country: a model. Research Policy 9, 254-277] model of acquisition, assimilation, and improvement is widely accepted to explain TC development in developing economies. However, some R&D practices we observed in Chinese manufacturing companies appear to be in disagreement with Kim's model. Based on four in-depth cases studies set in China's mobile phone industry, we hypothesize (a) a complementary stage in Kim's model, and (b) those stages can be traversed concurrently. r

This paper reviews the state of the art and current trends towards 3G and 3G+ mobile satellite systems that are being planned in parallel or within the International Mobile Telecommunications (IMT-2000) framework. The subject is firstly approached by introducing the key and enabling technologies both for satellites and high altitude platform stations. After having introduced an overall picture, another review is presented on physical layer research activities including propagation and channel modeling. Finally, the use of the reviewed channel models for Code Division Multiple Access system level analysis is introduced and some current efforts towards system design are presented. Copyright © 2002 John Wiley & Sons, Ltd.

ABSTRAK ANALISIS STRATEGI PENETAPAN HARGA JASA LAYANAN KOMUNIKASI ESIA SEBAGAI TITIK BALIK FAKTOR PENGUBAH PERILAKU PASAR. Telekomunikasi sebagai faktor penting dalam era globalisasi membuat jasa layanan komunikasi semakin berkembang pesat. Perkembangan jasa layanan komunikasi yang demikian pesat tidak lepas dari perilaku pasar yang responsif. Pembentukan perilaku pasar ini, tidak lepas dari kemunculan produk Esia yang membuat harga layanan jasa menjadi semakin murah seiring dengan kemunculan. Penentapan dan strategi harga Esia dalam bersaing dengan produk sejenis di pasar telekomunikasi seyogyanya mampu menurunkan harga jasa layanan telekomunikasi secara nasional. Esia sebagai jasa layanan komunikasi dalam perkembangan telah berhasil menjadi salah satu faktor titik balik pengubah perilaku pasar dari inelastis menjadi elastis

User requirements are growing faster than ever and the limitations of the current mobile communication systems have forced the researchers to come up with more advanced and efficient technologies. 4G mobile technology is the next step in this direction. 4G is the next generation of wireless networks that will totally replace 3G networks. It is supposed to provide its customers with better speed and all IP based multimedia services. 4G is all about an integrated, global network that will be able to provide a comprehensive IP solution where voice, data and streamed multimedia can be given to users on an "Anytime, Anywhere" basis. At present we have many technologies each capable of performing functions like supporting voice traffic using voice over IP (VoIP), broadband data access in mobile environment etc., but there is a great need of deploying such technologies that can integrate all these systems into a single unified system. 4G presents a solution of this problem as it is all about seamlessly integrating the terminals, networks and applications. The race to implement 4G is accelerating as well as quite challenging. The aim of this paper is to highlight the benefits, challenges in deployment and scope of 4G technologies.

Orthogonal variable spreading factor (OVSF) codes are standard in third generation UMTS cellular systems. The efficient generation of these codes is essential for reducing the area and power of wireless transceivers. In this paper, the basic properties of this family of codes are analyzed from an RTL perspective and two efficient hardware code generators are proposed. Tradeoffs and design solutions as well as low power considerations are discussed. These results represent the first reported implementation of an OVSF code generator. 1 *

Multiuser underwater acoustic communication is one of the enabling technologies for the autonomous ocean-sampling network (AOSN). Multiuser communication allows vehicles, moorings, and bottom instruments to interact without human intervention to perform adaptive sampling tasks. In addition, multiuser communication may be used to send data from many autonomous users to one buoy with RF communications capability, which will then forward the information to shore. The two major signaling techniques for multiuser acoustic communication are phase-shift keying (PSK) direct-sequence spread-spectrum (DSSS) and frequency-shift keying (FSK) frequency-hopped spread-spectrum (FHSS). Selecting between these two techniques requires not only a study of their performance under multiuser conditions, but also an analysis of the impact of the underwater acoustic channel. In the case of DSSS, limitations in temporal coherence of the channel affect the maximum spreading factor, leading to situations that may be better suited to FHSS signals. Conversely, the multipath resolving properties of DSSS minimize the effects of frequency-selective fading that degrade the performance of FSK modulation. Two direct-sequence receivers potentially suitable for the underwater channel are presented. The first utilizes standard despreading followed by decision-directed gain and phase tracking. The second uses chip-rate adaptive filtering and phase tracking prior to despreading. Results from shallow water testing in two different scenarios are presented to illustrate the techniques and their performance.

There are public concerns regarding possible carcinogenic or cancer-promoting effects of radiofrequency electromagnetic fields (RF-EMFs) because of the extensive use of wireless mobile phones and other telecommunication devices in daily life. However, so far it is unclear if nonthermal exposure of single EMF exposure in animal studies has a direct influence on carcinogenesis. Here, carcinogenic effects of combined signal RF-EMFs on AKR/J mice, which were used for the lymphoma animal model, were investigated. Six-week-old AKR/J mice were simultaneously exposed to two types of RF signals: single code division multiple access (CDMA) and wideband code division multiple access (WCDMA). AKR/J mice were exposed to combined RF-EMFs for 45 min/day, 5 days/week, for a total of 42 weeks. The whole-body average specific absorption rate (SAR) of CDMA and WCDMA fields was 2.0 W/kg each, 4.0 W/kg in total. When we examined final survival, lymphoma incidence, and splenomegaly incidence, no differences were found between sham-and RF-exposed mice. However, occurrence of metastasis infiltration to the brain in lymphoma-bearing mice was significantly different in RF-exposed mice when compared to sham-exposed mice, even though no consistent correlation (increase or decrease) was observed between male and female mice. However, infiltration occurrence to liver, lung, and spleen was not different between the groups. From the results, we suggested that simultaneous exposure to CDMA and WCDMA RF-EMFs did not affect lymphoma development in AKR/J mice.

With an increase in the number of end users using internet services, the average data rate of 30 Mbps will not be in a position to accommodate the future mobile technology. So radio and mobile communication specialists started an R&D work on 4G mobile communication systems before even completing IMT-2000 system [2]. 4G is the fourth generation standard for cellular wireless communication. It can offer speed up to 100 Mbps for high mobility communication where else it can deliver up to 1 GB for low mobility communication. The main focus on 4G communication system is to integrate the existing wireless technologies like WCDMA, Wireless LAN, Bluetooth, HSUPA/HSDPA, 1xEVDO [1] . Stability of a system and quality of service will be ensured in 4G communication systems.

    Migrating from an existing system to new systems like 4G has a greater impact on lot of political and technical issues and it has huge challenges to overcome. This project work intends to deal with various factors like fundamental issues within a network technology, effective use of a spectrum, standards, and also about various services of 4G and its impact on future communication system. This project work will also exhibits the development, transition, and the future work with respect to deploying 4G.

In this paper, the performance of uncoded uplink transmissions in a broadband code division multiple access (CDMA) system using tapped delay line (TDL) antenna array under multipath conditions is investigated. An expression for broadband CDMA system is derived to calculate the optimal weights of TDL antenna array. Using the derived broadband expression, the performance of TDL antenna array is investigated and compared with that of the already existing narrowband systems. Simulation results show that TDL antenna array can reduce multipath fading and multiple access interference (MAI). It is shown that if the signal-tonoise ratio (SNR) level is maintained at 20 dB and two-ray channel model is used, two antennas with four taps each can support 30 users with a BER of 10 3 . If three-ray channel model is used, the same antenna arrangement is not enough to support 30 users. To support these 30 users with BER of 10 3 , the number of taps needs to be increased to eight. Finally, the number of taps needs to be further increased to 16 if four-ray channel model is used. Not only that, the SNR should also be increased to 25 dB to achieve the same BER. DS-CDMA system, several receiver structures, such as the decorrelator, the minimum mean square error (MMSE) receiver, the multistage parallel interference cancelation receiver, the successive interference cancelation receiver, and the decorrelating decision feedback receiver, have been investigated in DS-CDMA system in literatures . In DS-CDMA system using parallel interference canceler (PIC) receiver with four stages, the signal-to-noise ratio (SNR) required to achieve a BER performance of 10 3 is 8 dB, whereas the single-stage PIC receiver with feedback approach requires only 2 dB to achieve the same BER . The effect of using PIC in multiuser detection (MUD) scheme is also investigated in where the authors show its superiority in satellite systems using either CDMA or a combination of time division multiple access and CDMA techniques. Using combination of soft and hard PIC detectors, the authors provide a comparative study of improving system performance using more stages of PIC in MUD schemes. In , blind user identification detection (UID) scheme based on linear prediction algorithm for asynchronous DS-CDMA systems over multipath fading channels is investigated and compared with the existing subspace-based UID algorithms; the authors concluded the paper showing the superiority of their proposed scheme in asynchronous CDMA systems.

Two enhancements are proposed to the application and theory of support vector machines. The first is a method of multicategory classification based on the binary classification version of the support vector machine (SVM). The method, which is called the -ary SVM, represents each category in binary format, and to each bit of that representation is assigned a conventional SVM. This approach requires only log 2 ( ) SVMs, where is the number of classes. We give an example of classification on an octaphase-shift-keying (8-PSK) pattern space to illustrate main concepts.

This paper describes how CDMA (Code Division Multiple Access) technique in CDMA communication system is used. Walsh Hadamard orthogonal codes are used as orthogonal code words. DSK(Dsp Starter Kit -TMS320C6713) along with CCStudio V3.1 is used to simulate the whole process.Voice input (or Digital Data) is taken as information, which is broken as packets and transmitted using CDMA technique, the recieved data is Decoded and played back.

Wireless Sensor Network (WSN) is an attractive choice for a variety of applications as no wired infrastructure is needed. Other wireless networks are not as energy constrained as WSNs, because they may be plugged into the mains supply or equipped with batteries that are rechargeable and replaceable. Among others, one of the main sources of energy depletion in WSN is communications controlled by the Medium Access Control (MAC) protocols. An extensive survey of energy efficient MAC protocols is presented in this article. We categorise WSN MAC protocols in the following categories: controlled access (CA), random access (RA), slotted protocols (SP) and hybrid protocols (HP). We further discuss how energy efficient MAC protocols have developed from fixed sleep/wake cycles through adaptive to dynamic cycles, thus becoming more responsive to traffic load variations. Finally we present open research questions on MAC layer design for WSNs in terms of energy efficiency.

To address the concern for cellular phone electromagnetic interference (EMI) to aircraft radios, a radiated emission measurement process for CDMA and GSM (ETSI GSM 11.22) wireless handsets was developed. Spurious radiated emissions were efficiently characterized from devices tested in either a semi-anechoic or reverberation chamber, in terms of effective isotropic radiated power. Eight representative handsets (4 GSM, 4 CDMA) were commanded to operate while varying their radio transmitter parameters (power, modulation, etc.). This report provides a detailed description of the measurement process and resulting data, which may subsequently be used by others as a basis of consistent evaluation for cellular/PCS phones, Bluetooth, IEEE802.11b, IEEE802.11a, FRS/GMRS radios, and other portable transmitters. Aircraft interference path loss (IPL) and navigation radio interference threshold data from numerous reference documents, standards, and NASA partnerships were compiled. Using this data, a preliminary risk assessment is provided for CDMA and GSM wireless phone interference to aircraft localizer, Glideslope, VOR, and GPS radio receivers on typical transport airplanes. The report identifies where existing data for device emissions, IPL, and navigation radio interference thresholds needs to be extended for an accurate risk assessment for wireless transmitters in aircraft. . . Acknowledgements: Special thanks is extended to the University of Oklahoma Center for Wireless Electromagnetic Compatibility, whose team members provided reference material, consultation, test equipment, operational procedures and test support at NASA Langley Research Center for controlling GSM and CDMA handsets using keypad codes, base station simulators, and a test harness interface.

A sensor may be deployed in an open space; on a battle field in front of, or beyond, enemy lines; in the interior of industrial machinery; at the bottom of water Body; in a biologically and chemically contaminated field; in a commercial building; in a home; or in on a human body. It is not possible to recharge the batteries in all environments and hence lifetime of a sensor is very crucial. So to increase the lifetime, the sensors are grouped into clusters and information is exchanged with base station via cluster head. An energy efficient cluster head selection technique is required to increase the lifetime of WSN. The traditional LEACH protocol selects the cluster head by random time which may select low energy sensors as cluster head. In this paper, the cluster head selection is based on energy variable and mean distance of neighboring nodes. This methodology is implemented using both CDMA and TDMA approaches and results show that using the CDMA approach reduces the energy consumption and improves the network lifetime compared to TDMA approach.

Multi Carrier Code Division Multiple Access (MC-CDMA) is an attractive choice for high speed wireless communication as it avoids the problem of Inter Symbol Interference (ISI) and also exploits frequency diversity. In order to support multiple users with high speed data communications, the MC-CDMA technique is used to address these challenges. MC-CDMA experiences severe multipath fading which badly affects its performance. When transmission over fading channel multi-cell interference occurs and this degrades the performance of the system. This paper specially analyzes the BER performance under Rayleigh fading channel conditions of MC-CDMA in presence of AWGN (Additive White Gaussian Noise) using BPSK modulation for different number of subcarrier, different number of users using MATLAB program, and finally the paper also presents a comparison between simulated results, which shows the reduction in BER performance.

The network traffic in the upcoming wireless network is expected to be extremely nonstationary and next generation wireless networks including 3rd generation are expected to provide a wide range of multimedia services with different QoS constraints on mobile communication because of that there is no guarantee for a given system to provide good quality of service. So that there is a need to design an efficient queuing mechanism by which the QoS is going to be improved for wideband services. This paper proposes an efficient active queue management mechanism to control the congestion at the router. This paper is mainly aimed towards the WCDMA scheme for wideband services like video. So that it integrates the WCDMA with IR-RAN using active queue management. By simulation result our proposed WCDMA architecture along with active queue management (AQM) will achieves the effective peak signal to noise ratio (PSNR).

https://sites.google.com/site/ijcsis/

Spread spectrum code-division multiple-access (CDMA) systems are currently considered as very attractive alternatives to the more familiar FDMA and TDMA systems, especially in the presence of multipath fading and external interference. The problem of code selection in a CDMA system with a finite number of users is addressed in this paper. A simple and efficient method for the selection of finite code sets with relatively high processing gain from Gold and Kasami code families of relatively large sizes is described in detail. Selected code sets of period 63 are presented along with their overall average performance parameters for different number of users.

This paper gives an overview on communications system based and global navigation satellite system (GNSS) based navigation. Starting from the physical layer model of a mobile communications or navigation receiver, we highlight similarities and differences between the two receivers. We explain navigation principles for timing measurements and present the possible navigation accuracies of different communications systems and GNSSs. Finally, we examine synergies of combined receivers and systems.

In this paper we consider distributed power control in a multicell wireless data system and study the effect of pricing transmit power. Drawing on our earlier work in [1], we formulate the QoS of a data user via a utility function measured in bits per Joule. We consider distributed power control, modeled as a non-cooperative game, where users maximize their utilities in a multicell system. Base station assignment based on received signal strength as well as received signal-to-interference ratio (SIR) are considered jointly with power control. Our results indicate that for both assignment schemes, such a procedure results in an inefficient operating point (Nash equilibrium) for the entire system. We introduce pricing of transmit power as a mechanism for influencing data user behavior and our results show that the distributed power control based on maximizing the net utility (utility minus the price) results in improving the Pareto efficiency of the resulting operating point. Variations of pricing based on global and local loading in cells are considered as a means of improving the efficiency of wireless data networks. Finally, we discuss the improvement in utilities through a centralized scheme where each base station (BS) calculates the best SIR to be targeted by the terminals it is assigned.

Long Term Evolution (LTE) network deploys Orthogonal Frequency Division Multiple Access (OFDMA) technology for downlink multi-carrier transmission. To meet the Quality of Service (QoS) requirements for  LTE networks, packet scheduling has been employed. Packet scheduling determines when and how the user’s packets are transmitted to the receiver. Therefore effective design of packet scheduling algorithm is an important discussion. The aims of packet scheduling are maximizing system throughput, guaranteeing  fairness among users, and minimizing either or both Packet Loss Ratio (PLR)and packet delay. Inthis paper, the performance of two packet scheduling algorithms namely Log Maximum-Largest Weighted Delay First (LOG-MLWDF) and Max Delay Unit (MDU), developed for OFDM(Orthogonal Frequency Division  Multiplexing)networks, has been investigated in LTE downlink networks, and a comparison of those algorithms with a well-known scheduling algorithm namely Maximum-Largest Weighted Delay First(MLWDF) has been studied.The performance evaluation was in terms of system throughput, PLR and  fairness index. This study was performed for both real time (voice and video streaming)and non-real time (best effort)perspectives. Results show that for streaming flows,LOG-MLWDF shows best PLR  performance among the considered scheduling schemes, and for best effort flows, it outperforms the other two algorithms in terms of packet delay and throughput.

International Conference on Signal Processing and Communication - ICSPC'17
July 28-29 2017 Coimbatore, Tamil Nadu, India

The conference aims to bring together the Scientists, Scholars, Engineers, Industrialists and Students from in and around the world to present and share their knowledge and experience on the on-going research activities and hence to foster research relations between universities and industries. This conference provides opportunities for the delegates to exchange new ideas, insights, applications and experiences, to establish research relations and to find global partners for collaborations and to solve future problems in signal processing and communication.

=== Important Dates ===

March 15, 2017........................Tutorial  Special Session proposals
March 15, 2017.........................Paper submission deadline
April 15, 2017........................... Notification of acceptance
April 30, 2017............................Camera-ready paper submission
July 28-29, 2017........................ICSPC17 Conference

The authors are invited to submit technical papers of their original, unpublished work under the below-mentioned sub-themes. The works within the broad areas (but not limited to) are acceptable for the presentation in the conference.

Track 1
Bio-Signal Processing
Audio/Speech Processing and Coding
Statistical Signal Processing
Signal Processing for Communications
Medical Image Processing
Array Signal Processing
Soft Computing for Image Processing
Remote Sensing
Signal Processing for Security
Video Processing
Biometrics
Cryptography/Steganography/Watermarking
VLSI Signal Processing

Track 2

Mobile and Cellular Communications
Vehicular Communication Networks
Wireless Sensor Networks
Antennas, RF, and Microwave Communications
Optical Communication
MIMO and Space-Time Communications
Cognitive Radio and Cognitive Networks
Satellite Communication
Virtual Reality and Gaming
OFDM and CDMA Communication Receivers

Data Communications concerns the
transmission of digital messages to devices external
to the message source. However, the aim of any
communications system is to provide the highest
possible transmission rate at the lowest possible
power and with the least possible noise. In this
research paper, it is required to acquire two audio
voice signals with 8 bits of resolution and 8 kHz
sampling frequency for 5 seconds. First audio voice
signal for 5 seconds indicated as “My name is Ali
Tariq Bhatti. I am doing research in Reed-Solomon
and CDMA for an assigned task”. Second audio
voice signal for 5 seconds indicated as“My name is
Friendz. I am doing research in Reed-Solomon and
CDMA for an assigned task”. However, in this
research paper, two MAT files will be loaded and
then, store the two recorded audio voice signals that
is one of mine and my friend in ‘.wav’ format in one
of each MAT file. As both acquired voice signals
must have sufficient amplitude without clipping it to
allow one listen to the voice clearly when played.
The two recorded voice signal of ‘.wav’ file because
of CDMA implementation required in this research
paper was also then read by MATLAB for further
processing. The implementation of the Reed-
Solomon code using Additive White Gaussian Noise
(AWGN) channel to perform the recorded voice
signal to be read, simulated, transmitted and received.
However, this memory-less AWGN channel shows
noise to transmit and receive the voice signal. So,
sampled both audio voice signals by 8 KHz sampling
frequency, quantize using 8-bit μ-law companding
on-uniform quantizer, and modulate the signal by
Binary phase shift keying (BPSK). BPSK is the
modulation achieved by as system bandwidth isn’t a
constraint. The standard deviation of this AWGN is
considered to be 0.8. In addition, designed an
algorithm for Reed-Solomon channel coding with
CDMA implementation and verify the performance
of the algorithm by playing the two original and the
two received voice signals. After doing modulation
process through BPSK, spread the coded CDMA for
both audio voice signals by adding them. Then,
simulated the AWGN noise and after that dispread
both the received signals and demodulated it. BER
Performance computed between Theoretical and
Empirical. At the last, Mean Square Error is
calculated for Signal-to-Noise ratio between the
errors of two audio voice signals before and after
transmission. So, then verified work to the
requirement of this research by making a comparison
of both the original and received voice signals via
playing back both signals. Moreover, the comparison
of both the voice signals before they are transmitted
and after they are received can be evaluated by the
effectiveness of the R-S coding. Therefore, R-S
channel coding is a very efficient technique for signal
transmission by making these comparisons.

Mobile communication has been readily available for several years, and is major business today. It provides a valuable service to its users who are willing to pay a considerable premium over a fixed line phone, to be able to walk and talk freely. Because of its usefulness and the money involved in the business, it is subject to fraud. Unfortunately, the advance of security standards has not kept pace with the dissemination of mobile communication.
Some of the features of mobile communication make it an alluring target for criminals. It is a relatively new invention, so not all people are quite familiar with its possibilities, in good or in bad. Its newness also means intense competition among mobile phone service providers as they are attracting customers. The major threat to mobile phone is from cloning.

This article presents a survey on medium access control protocols for wireless multimedia networks. A basic overview of MAC protocol concepts is presented, and a framework is developed for comparisons. The MAC protocols covered in this article include Random Access protocols, Contention less protocols, TDMA CDMA, third-generation WCDMA schemes and Hybrid protocols proposed for wireless Multimedia Networks. The operation of each protocol is explained, and its advantages and disadvantages are presented. Finally, a qualitative comparative outline of the discussed protocols is provided.

With the standardization of CDMA2000-1x, EVDO, and its subsequent release/revisions (0, A, B, and C) each telecom vendor continues to develop their equipment as well as network management software for supporting EVDO services and defines EVDO performance parameters separately. This leads to sort of redundancy and perplexity in multivendor network environments in which network optimization engineer
has to deal with all these performance parameters to optimize the system performance. There is need to unify these different EVDO performance parameters defined by different vendors to overcome this redundancy and confusion. To complete this objective we first has identified different EVDO key performance indicators defined by different vendors through their software i.e. element management systems (EMS). After identification of these KPIs we then take one most important KPI i.e., the Session Setup Success Rate (SSSR) and analyses its constituent counters and find out differences through daily
statistic reports, standard definitions formula and message flow diagrams defined by each vendor. Then we proposed a new KPI, HSN Ratio (Harmonic mean of session setup success and session negotiation success Ratios) to get a complete picture of end-to-end session setup success rate. Finally we have collected 15 days hourly statistic report of SSSR and session negotiation success rate defined by each vendor through their EMS’s and applied minimum mean square error method to unify the proposed HSN ratio. As a result of this process we have figure out differences between multivendor KPIs and minimizes these differences to unify them. Similarly this whole process could be repeated to unify other EVDO KPIs.

One of the research challenges in cellular networks
is the design of an efficient model that can reduc
e call
blocking probability and improve the quality of ser
vice (QoS) provided to mobile users. Blocking occur
s
when a new call cannot be admitted into the network
due to channel unavailability caused by limited
capacity or when an ongoing call cannot be continue
d as it moves from one base station to another due
to
mobility of the user. The proposed model computes
the steady state probability and resource occupancy
distribution, traffic distribution, intra-cell and
inter-cell interferences from mobile users. Previou
sly
proposed models are reviewed through which the pres
ent model is built for use in emerging wireless
networks so as to obtain improved QoS performance.
The developed model is validated through simulation
s
in MATLAB and its equations implemented using Java
Programming Language. The results obtained
indicate reduced call blocking probability below th
reshold.

We consider joint beamforming (BF) and power control to minimize cochannel interference in a CDMA wireless uplink, where an antenna array of different geometries receives from single-antenna wireless users. The problem is to find the optimum beamforming weight vector and the minimum transmission power of each terminal such that the quality of service (QoS) requirements of the users are fulfilled and the so-called near-far effect is alleviated. This will increase the channel capacity and further prolongs the battery lives of the mobile terminals. The particle swarm optimization method is used to determine the optimum beamforming weight vector and the minimum transmission power of each terminal. Uniform linear and circular array geometries are considered, with and without correlated shadow fading. Simulation results illustrate the advantage of using BF jointly with power control and the robustness of the optimization technique used.

In the design of mobile ad hoc networks, a challenging problem is how to route information reliably and efficiently from one node to another in moderate to high level of mobility. Due to mobility, limited residual energy of the node, selection of stable and durable path for the communication is the challenge. Also remaining queuing capacity is also affected on the packet loss. Many proposals have been addressed to this problem; however, few papers consider a proactive protocol like Optimized Link State Routing Protocol (OLSR) to better manage the energy consumption and link stability in routing path selection algorithms. In this paper, we explored modification to MPR selection and integrating appropriate routing metrics in the routing decision scheme to lessen effects of reason that lead to more packet loss. Our power-aware version of OLSR is proven by simulations in NS3 under a range of different mobile scenarios and network density. Significant performance gains are obtained in terms of packet loss ratio and MPR count for our modified OLSR version.

The increase in the consumer demand and the exponential growth for wireless systems, which enables consumer to communicate in any place by means of information, has in turn led to the emergence of many portable wireless communication products. The present research works primarily targets to integrate as much as signal processing applications in a single portable device. Since integration through software applications compromises system speed, integration through hardware will be the better compliment. Software Defined Radio (SDR) Technology yields to achieve this small form factor system while keeping power consumption under the limit. SDR enables soft changeable system functionality, such as receiver demodulation technique .In this implementation two type modulation techniques are used, ASK and FSK. The flexibility of changing the receiver functionality in runtime is usually attained by FPGA. However, using a complete FPGA for reconfiguration of a particular functionality is not an efficient method in terms of power consumption and switching time. We proposed a SDR architecture using a recent advancement in FPGAs, called Partial Reconfiguration (PR). PR helps to change certain portion of FPGA, while the rest keeps functioning. It also reduces the total hardware usage and hence the power. The different demodulation technique and other signal processing application from an external memory unit can be loaded into FPGA PR modules while the other parts of FPGA doing a constant data processing.

Hierarchical Genetic Algorithms (HGA) as a tool for search and optimizing methodology have now
reached a mature stage. The minimum resource facility to carry user traffic, termed a channel unit (CU),
is composed of a one time-slot and one code in the TD-CDMA/TDD system. The control of the number of
CUs depends on the traffic load solves varied and asymmetrical traffic problems in the 3G system. In a
cellular network, the call arrival rate, call duration and the communication overhead between the base
stations and the control center are vague and uncertain, regardless of whether the criteria of concern are
nonlinear, constrained, discrete or NP hard. In this paper, the HGA is used to tackle the neural network
(NN) topology as well as the fuzzy logic controller for the dynamic CU allocation scheme in wireless
cellular networks. Therefore, we propose a new efficient HGA CUs Allocation (HGACA) in cellular
networks. It aims to efficiently satisfy the diverse quality-of-service (QoS) requirements of multimedia
traffic. The results show our algorithm has a lower blocking rate, lower dropping rate, less update
overhead, and shorter channel-acquisition delay than previous methods.

Constant modulus transforms like discrete Fourier transform (DFT), Walsh transform, and Gold codes have been successfully used over several decades in several engineering applications, including discrete multi-tone (DMT), orthogonal frequency division multiplexing (OFDM) and code division multiple access (CDMA) communications systems. In this paper, we present a generalized framework for DFT called Generalized DFT (GDFT) with nonlinear phase by exploiting the phase space. We show that GDFT offers sizable correlation improvements over DFT, Walsh, Oppermann and Gold codes, leading to better performance in all multi-carrier communications scenarios investigated. We also highlight how known constant modulus orthogonal transforms are special solutions of the proposed GDFT framework. Moreover, we introduce practical design methods offering computationally efficient implementations of GDFT as enhancements to DFT. We conclude the paper with examples of communications applications where GDFT is shown to outperform DFT and other known constant modulus bases.

As over 70 percent of the earth's surface is covered by water, it is desirable to deploy underwater sensor networks to support oceanic research. Under Water Sensor Networks (UWSNs) use acoustic waves and are characterized by long and variable propagation delays, intermittent connectivity, limited bandwidth and low bit rates. Energy savings have always been the primary concern in wireless sensor network protocols; however there are applications where latency and throughput are prioritized over energy efficiency and are so significant that the application would not be able to satisfy its requirements without them. Although existing duty-cycle MAC protocols are power efficient, they introduce significant end-to-end delivery latency, provide poor throughput and are not suitable for the challenging environment of an UWSN. In this paper, we utilize CDMA as the underlying multiple access technique, due to its resilience to multi-path and Doppler's effects prevalent in underwater environments. We propose UW-MAC, a CDMA-based power controlled medium access protocol that uses both transmitter based and receiver based CDMA inside a formed cluster, and uses a TDMA schedule to make the cluster heads communicate with the base station. Our MAC algorithm targets latency and throughput needs in addition to its ability to increase the overall network lifetime. We discuss the design of UW-MAC, and provide a head-to-head comparison with other protocols through extensive simulations focusing on the performance in terms of latency, throughput and energy consumption.

We present a geolocation method for GSM/CDMA/UMTS networks. A cell area is partitioned into a grid, and a sequential Bayesian updating scheme is proposed to identify the grid point within the circular belt, defined by the one-way delay between the mobile and the base station, that is the most likely position of the user. Using GSM as case study, we employ an RF simulation model to study the accuracy of the algorithm compared to existing methods. We show that the accuracy of the Bayesian update method is relatively insensitive to cell size and robust to parameter settings.

Orthogonal frequency division multiplex (OFDM) modulation is being used more and more in telecommunication both in wired and wireless. This modulation technique has several advantages, reason for its increasing usage in communication. OFDM can provide high data rates, it can be implemented easily, it is spectrally efficient and with sufficient robustness to channel imperfections. On the other hand most third generation mobile phone systems are using Code Division Multiple Access (CDMA) as their modulation technique. For this reason, CDMA is also investigating so that the performance of both CDMA and OFDM can be compared. It is found that OFDM performs extremely well when compared with CDMA, and provide very high tolerance to multipath delay spread, channel noise, and peak power clipping. In addition to this it provides a high spectral efficiency The noise performance of OFDM is found to depend solely on the modulation technique used for modulating each carrier of the signal. The OFDM signal performance is found to be the same as for a single carrier system, using the same modulation technique and can provide large data rates with sufficient robustness to radio channel impairments The minimum signal to noise ratio (SNR) required for BPSK was ~7 dB, where as it was ~12 dB for QPSK and ~25 dB for 16PSK. CDMA was found to perform poorly in a single cellular system, with each cell only allowing 7-16 simultaneous users in a cell, compared with 128 for OFDM.1.25 MHz bandwidth and 19.5 kbps user data rate was used for it. This low cell capacity of CDMA was attributed to the use of non-orthogonal codes used in the reverse transmission link, leading to a high level of inter-user interference.

In this paper, we derive the error probability
of multi-hop networks employing code-division multiple
access transmission in amultiuser environment. The standard
Gaussian approximation is used tomodel themultiple access
interference in the network.We consider multi-hop networks
employing serial, parallel, and selection relaying using the
decode-and-forward technique. For the selection relaying,
we consider two schemes; namely, the threshold-based relay
selection and the maximum relay selection. In addition, we
investigate the effect of different system parameters on the
error performance of the system, such as the spreading gain,
the number of interfering users, and the path loss exponent.
Results show that as the number of users increases,
the improvement coming from the relaying decreases.

This paper reviews the state of the art and current trends towards 3G and 3GC mobile satellite systems that are being planned in parallel or within the International Mobile Telecommunications (IMT-2000) framework. The subject is firstly approached by introducing the key and enabling technologies both for satellites and high altitude platform stations. After having introduced an overall picture, another review is presented on physical layer research activities including propagation and channel modeling. Finally, the use of the reviewed channel models for Code Division Multiple Access system level analysis is introduced and some current efforts towards system design are presented.

This paper analyzes the performance of Wireless CDMA when high power amplifier use in the processing block of this. The simulation is carried out on MATLAB 7.8.1, the result shows the BER, MER comparison of WCDMA with using and without using high power amplifier. In this paper author analysis the WCDMA System without high power amplifier and with high power amplifier and the calculation of AWGN channel 15 db SNR, Received Signal via High efficiency power amplifier is plotted, AM/ PM response of resultant signal is plotted. BER, MER is calculated as a parameter to judge the performance of the proposed system.

Novel objectives such as very low outage, high capacity, and high throughput are major challenging problems in radio resource management of mobile communication systems. More specifically, in radio resource scheduling (RRS), the aim is how to optimize available resources such as transmission power and data rate to achieve certain targeted objectives. Conventional RRS algorithms are based on optimizing one objective while keeping others as constraints. This paper proposes a novel distributed RRS algorithm based on analytic multi-objective optimization. The proposed algorithm relaxes the constraints and jointly optimizes all the required objectives. Infinity set of optimal solutions, called Pareto optimal, is obtained. Each solution in the set is optimal in a specific sense. The decision maker selects the required solution that fulfills the network requirements and conditions. Some of the conventional RRS algorithms are special cases of our multi-objective based algorithm. Detailed mathematical analysis of the proposed algorithm is given. Simulation results show the behavior of the proposed algorithm as well as its advantages over conventional algorithms.

Channel modeling is a fundamental research area in wireless communication due to the complexity of the signal propagation process. To design these new wireless systems, it is essential to use channel models. It plays a crucial role in the investigation of MIMO system capacity. The independent and identically distributed (i.i.d.) channel model has been used by researchers to derive the useful bounds of MIMO capacity. The SCM (Spatial Channel Model) is an example of a more realistic channel model. It is a standardized model developed by 3GPP-3GPP2 spatial channel model (SCM) ad-hoc groups (AHG), which are standardization bodies for 3G cellular systems. This model allows us to perform system level simulations and offers three propagation scenarios for investigation: suburban macro-cell, urban macro-cell and urban micro-cell.

Wireless communication now has been focus to increase data rate and high performance. The
multi carrier on multi-hop communication system using relay's diversity technique which is
supported by a reliable coding is a system that may give high performance.
This research is developing a model of multi carrier CDMA on multi hop communication
system with diversity technique which is using Alamouti codes in Rayleigh fading channel. By
Alamouti research, Space Time Block Code (STBC) for MIMO system can perform high quality
signal at the receiver in the Rayleigh fading channel and the noisy system. In this research,
MIMO by STBC is applied to single antenna system (Distributed-STBC/DSTBC) with multi
carrier CDMA on multi hop wireless communication system (relay diversity) which is able to
reduce the complexity of the system but the system performance even can be maintained and
improved.
MC CDMA on multi hop wireless communication system with 2 hops is performing much better
than Single Input Single Output (SISO) system (1 hop system). Power needed for 1 hop system to
have the same quality as 2 hops system to reach BER 10-3 is 12 dB. And multi hop system needs
orthogonal symbol to send from relay than original symbol to reach better performance. 12.5
dB power up is needed for multi hop system which sent same symbol as transmitter than relay
system which sent orthogonal symbol.

Over the past few years, many projects using code division multiple access (CDMA) techniques have being investigated. These systems are known to have many advantages over FDMA and TDMA one being its robustness against interference. The GPS system is a well-known application of CDMA techniques. Nevertheless, it appears in many papers and reports that GPS receivers may be disturbed by several types of interference. Mitigation techniques to combat these interferences and to improve the pre-correlation signal-to-noise ratio are to be developed to enhance the GPS receiver robustness. This paper starts with an overview of potential pre-correlation mitigation solutions for the GPS receiver. A potential mitigation technique for RF interference rejection on the GPS C/A-code of a receiver for aeronautical applications is investigated. The principle of the implementation of the adaptive transversal filter solution is shown. In order to evaluate the anti-jamming capability for civil use, a GPS receiver simulator has been developed using the communication systems simulation software COSSAP. It appear that using a notch filter in DSP just after the analogue-to-digital converter (ADC) and in front of the digital loops (DPLL and DDLL) provides significant improvements. Attenuation of the continuous wave interference (CWI) from 30 to 55 dB have been measured. This paper is not restricted to the GPS system but also gives an overview of notch filtering which is well suited for CDMA as a potential mitigation technique