: We demonstrate an all-fiber fast optical frequency-hop code division multiple access (FFH-CDMA) for high bandwidth communications. Transmission rates of up to 1.6 Gb/s per user were achieved with an 8-wavelength multiple Bragg grating written in 8 cm of fiber. Introduction Code division multiple access ...
E-print Network
This effort demonstrated the interference mitigation capabilities of the auxiliary vector (AV) receiver for video transmission over direct-sequence code division multiple access (DS-CDMA) systems. The proposed receiver design is compared to the convention...
National Technical Information Service (NTIS)
This paper introduces a new class of precision timing and frequency reference that indirectly receives GPS timing and frequency information via the transmissions from Code Division Multiple Access 'CDMA' mobile telecommunications base stations operating i...
Anew slotted multi-code code division multiple access (CDMA) protocol is proposed for wireless packet networks. On the uplink, request attempts are made simultaneously with transmission of data packets, by selecting one of request minislots with a randomly chosen code. The performance of the proposed protocol is evaluated bysimulation ...
network supporting multi-hop transmissions, MAC should be jointly designed with call admission controlDistributed Medium Access Control for Next Generation CDMA Wireless Networks Hai Jiang, Princeton wireless networks are expected to have a simple infrastructure with distributed control. In this article
In this letter we present a simplified proof for the convergence of the windowed Cholesky factorization of the time-varying asynchronous code-division multiple-access (CDMA) channel. Index Terms---Filter tap convergence, multiuser CDMA. I. INTRODUCTION T HE DETERMINATION of the whitening matched filter (WMF) for the time-invariant ...
Orthogonal Frequency Division Multiplexing (OFDM) is a widely used technique for data transmission on multipath fading channels. The multipath component of these types of channels causes a phenomenon known as frequency selective fading. This type of fading can severely degrade or completely eliminate the signal energy of many of the OFDM tones producing an irreducible error ...
NASA Astrophysics Data System (ADS)
In this paper, we consider the problem of video transmission over wireless generalized multicarrier code division multiple access (GMC-CDMA) systems. Such systems offer deterministic elimination of multiple access interference. A scalable video source codec is used and a multirate setup is assumed, i.e., each video ...
PubMed
An integrated system for code division multiple access (CDMA) radio access to asynchronous transfer mode (ATM) network is considered. The inherently high error rate associated with the Rayleigh fading channel is overcome by two-dimensional CRC codes for efficient ATM-CDMA interfacing. Simulations show promising ...
... Accession Number : ADA221804. Title : Throughput Performance of a Direct Sequence CDMA Packet Radio Network. Descriptive ...
DTIC Science & Technology
Orthogonal Frequency Division Multiplexing (OFDM) is a very popular technique used for data transmission on multipath fading channels. The multipath component of these types of channels causes a phenomenon known as frequency selective fading. This type of fading can severely degrade or completely eliminate the signal energy of many of the OFDM tones producing an irreducible ...
One of the key limitations of Orthogonal Frequency Division Multiplexing (OFDM) waveforms when used for data transmission on multipath fading channels is frequency selective fading. This type of fading can cancel out or severely degrade the signal strength of many of the OFDM tones, producing an irreducible error rate. In the early 1990"s, researchers combined some of the ...
The paper presents a twin-class unequal protected video transmission over mobile channels. As a transport vehicle, we have considered CDMA-2000. A dual priority transmission has been invoked in CDMA-2000 by adopting a relative gain adjustment strategy for...
Time-varying multipath fading associated with the wireless link limit the capacity of a wireless system. To adapt to this adverse radio environment efficiently, we investigate the use of a pilot-aided fade-resistant transmission scheme for the uplink of a chip-interleaved code division multiple access (CDMA) system. We analyze the ...
A multi-media multi-rate CDMA network is introduced in this paper. Multi-rate CDMA networks not only can transmit information sources with different data rate but they can also accommodate more users by adjusting the transmission rate. The multi-rate CDMA system is designed as a fixed-chip-rate variable-data-rate ...
Wireless access in hybrid fiber/coax (HFC) networks can integrate two major telecommunication infrastructure, i.e., wireless and HFC networks. This paper studies the technical feasibility of integrating IS-95 code-division-multiple- access (CDMA) wireless networks and HFC networks. Capacity estimation of an HFC optical node-based ...
A novel multiple access scheme based on slow frequency hopping multicarrier direct-sequence code division multiple access (SFH/MC DS-CDMA) is proposed and investigated, which can be rendered compatible with the existing second-generation narrowband CDMA and third-generation wideband CDMA ...
This project is focused on the development of advanced components and system technologies for secure data transmission on high-speed fiber optic data systems. This work capitalizes on (1) a strong relationship with outstand ing faculty at the University o...
In this letter, we report results on the relative performance of scalable video transmission via a singlerate or a multirate direct sequence code-division multiple-access (DS-CDMA) channel using minimum total squared correlation (TSC) spreading codes. Our findings demonstrate the superiority of the multirate system on a wide range ...
, compared with the soft handoff policy be- cause high transmission power near the cell boundary of various types of data services by restricting the high power transmission of user packets in the soft access scheme on the reverse link is employed to support data services. A soft handoff policy, hard
... Accession Number : ADA415141. Title : Smart Antenna in DS-CDMA Mobile Communication System Using Circular Array Technique. ...
... Accession Number : ADA407090. Title : Smart Antenna Application in DS-CDMA Mobile Communication System. Descriptive Note : Master's thesis. ...
... Accession Number : ADA447434. Title : Multiuser Detectors for MIMO DS/CDMA Systems. Corporate Author : NATIONAL ...
... Accession Number : ADA220189. Title : High-Throughput, Survivable Protocols for CDMA Packet-Radio Networks (SRNTN-74). ...
... Accession Number : ADA527820. Title : Coded DS-CDMA Systems with Iterative Channel Estimation and no Pilot Symbols. ...
(pseudo-noise) spreading sequences as pseudo-noise CDMA (PN-CDMA). The second basic CDMA technique is also INTRODUCTION Code-division multiple access (CDMA) has become very popular in recent years, not only in mobile be viewed as a multidimensional modulation whose bandwidth occupancy and ...
Throughout this paper, a closed form expression of the multiple access interference (MAI) limited bit error rate (BER) is provided for the multiwavelength optical code-division multiple-access system when the system is working above the nominal transmission rate limit imposed by the passive encoding-decoding operation. This system is ...
The design of the CDMA modem of small terminals for a Spread Spectrum Code Division Multiple Access (SS-CDMA) communication network is described. For the implementation of this access scheme the large set of Kasami sequences with a code length of 1023 chi...
Optical code division multiple access (O-CDMA) uses very narrow transmission pulses and is thus susceptible to fiber optic link impairments. When the O-CDMA is implemented as wavelength/time (W/T) matrices which use wavelength division multiplexing (WDM) sources such as multi-frequency laser transmitters, the ...
Energy Citations Database
In this paper, a new multirate optical network based on a hybrid slotted-ALOHA (S-ALOHA)/overlapped code division multiple access (O-CDMA) system is proposed as an effective way of integrating multiclass traffic. The key issue in this proposal is to exploit the potential of the optical O-CDMA using fiber Bragg gratings when jointly ...
7. Multiple Access Husheng Li Dept. of Electrical Engineering and Computer Science Spring, 2008Multiple Access TDMA CDMA OFDM Random Access Tackling Interference Wireless Communications Chapter #12;Multiple Access TDMA CDMA OFDM Random Access Tackling ...
We propose a novel asynchronous direct-sequence codedivision multiple access (DS-CDMA) using feedback-controlled spreading sequences (FCSSs) (FCSS/DS-CDMA). At the receiver of FCSS/DS-CDMA, the code-orthogonalizing filter (COF) produces a spreading sequence, and the receiver returns the spreading sequence to the ...
Performance of an Indoor Optical Wireless PPM-CDMA System with Interference Cancellation schemes-2-880-8224 Abstract - A new puke position modulation - code division multiple access (PPM-CDMA) system is proposed that PPM-CDMA systems with both decorrelating detection and SIC achieve signifcant SNR improvement over
... or realize it, the basic idea behind this ... channel under the assumption that the channel ... CDMA (Code Division Multiuser Access) communication is a ...
... orthogonal codedivision multiple-access (CDMA) systems for efficient communication in environments subject to multipath fading phenomen& The ...
. Handoffs due to user mobility require network signaling to maintain the communication link and may result link transmission accuracy. Key words: Handoff, wireless multimedia communications, code for wireless multimedia communications, and addresses the handoff issues in the network. With the CDMA
The present invention relates generally to an optical CDMA transmission system and method employing differential optical encoding and bipolar decoding. Differential encoding and bipolar decoding may be performed at the bit level, wherein differential phas...
This work deals with synchronous CDMA transmission using orthogonal channel codes in frequency selective multipath. The motivating application is the Forward Link in 3G CDMA Cellular Systems. In saturated systems, the intra-cell Multi-user Access Interference created by the multipath causes the RAKE receiver to ...
The transmission of both optical code division multiple-access (OCDMA) and wavelength division multiplexing (WDM) users on the same band is investigated. Code pulses of spectral amplitude coding (SAC)/optical code division multiple-access (CDMA) are overlaid onto a multichannel WDM system. Notch filters are ...
Multi-carrier code division multiple access (MC-CDMA) has been considered as one of the promising techniques for the next generation of mobile communication systems because of its efficient bandwidth usage, robustness to the multi-path fading and simple channel-sharing scheme. However, MC-CDMA cannot be employed in the uplink ...
We describe a receiver that performs optical code division multiple access (O-CDMA) decoding followed by pulse position modulation (PPM) symbol detection that behaves like a radar quadrant receiver. Simulations determine the impact of multi-access interference on symbol detection for up to 32 users.
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Spread-spectrum code division multiple access (CDMA) and single channel per carrier frequency division multiple access (FDMA) systems are compared for spectrum efficiency. CDMA is shown to have greater maximum throughput than FDMA for the MobileStar(sm) system which uses digital voice activated carriers and ...
Subchannel allocation for the reverse link of multicarrier code- division multiplex-access (MC-CDMA) system with adaptive frequency hopping (AFH) is investigated. An efficient allocation method that can be employed with the matched filter (MF) receiver as...
The design of the CDMA modem of small terminals for a Spread Spectrum Code Division Multiple Access (SS-CDMA) communication network is described. For the implementation of this access scheme the large set of Kasami sequences with a code length of 1023 chips was chosen. Synchronization of the receiver reference code ...
Most of the Radio Frequency Identification (RFID) systems operating in HF and UHF bands employ narrowband modulations (FSK or ASK) with Manchester coding. However, these simple transmission schemes are vulnerable to narrowband interference (NBI) generated by other radio systems working in the same frequency band, and also suffer from collision problem and need special ...
We present an adaptive video transmission scheme for use in a code-division multiple-access network, which incorporates efficient bandwidth allocation among source coding, channel coding, and spreading under a fixed total bandwidth constraint. We derive the statistics of the received signal, as well as a theoretical bound on the packet drop rate at the ...
This project is focused on the development of advanced components and system technologies for secure data transmission on high-speed fiber optic data systems. This work capitalizes on (1) a strong relationship with outstanding faculty at the University of California-Davis who are experts in high speed fiber-optic networks, (2) the realization that code division multiple ...
... Title : A Direct Sequence - Code Division Multiple Access/Binary Phase Shift Keying (DS-CDMA/BPSK) Modem Design. ...
We propose fast optical frequency-hop code division multiple access (FH-CDMA) for high bandwidth local area networks. Encoding and decoding are achieved by tunable fiber Bragg gratings. Frequency hopping offers many advantages compared to the previously proposed optical CDMA multiple access techniques. The ...
Catalog Description: Basic concepts of signals and information transmission. Fundamental features of transmission channels. Switching techniques for computer communication. Frequency and time division multiplexing for communication networks. Code division multiple access (CDMA) technique. Modulation, modems, and ...
We report measurements on what an eavesdropper ''sees'' when tapping into a wavelength/time O-CDMA system in which 16 of 32 codes are ''lit''. Severe multi-access interference (MAI) provides some data confidentiality.
We demonstrate a BER of 10{sup -11} for 16 simultaneous users, using wavelength/time O-CDMA. We show the extent to which severe multi-access interference can be used to mask and/or degrade the signal from an intruder.
... network of half-duplex radios. ... transmissions and stability of a slotted single hop network ... for all transmitter-receiver pairs, and the thermal noise level ...
The future 3G/4G wireless communication systems will provide internet access for mobile users. Packet scheduling algorithms are essential for QoS of diversified data traffics and efficient utilization of radio spectrum. This paper firstly presents a new packet scheduling algorithm DSTTF under the assumption of continuous transmission rates and scheduling ...
With multiple overlapped piconets, the IEEE 802.15.3 Medium Access Control (MAC) protocol uses a Parent/Child (P/C) or Parent/Neighbor (P/N) configuration to avoid inter-piconet interference. However, the throughput of a P/N or P/C configuration cannot exceed that of a single piconet. In the present paper we propose an efficient means of managing multiple piconets to cooperate ...
Work Item Description Analysis of the feasibility of a satellite based broadcast layer using the UTRA FDD W-CDMA technology to complement UTRAN and possibly GERAN. 1 3GPP Work Area
... Accession Number : ADA415205. Title : Uniform Circular Antenna Array Applications in Coded DS-CDMA Mobile Communication Systems. ...
... Second, the broad band nature of these modes may allow quantum CDMA-type teleportation schemes for multi-user access. ...
... CA Cooperative Agreement CAD Computer-aided Design CAM Computer- aided Manufacturing CDMA Code Division Multiple Access ...
... Accession Number : ADA371495. Title : Linear Interference Suppression and Pulse Optimization for DS-CDMA. Descriptive Note : Final rept. ...
... from CDMA (code division multiple access) multiuser detection. 4. Independent component analysis (ICA). He will employ MATLAB and SIMULINK ...
A Handoff Control Scheme Using a Restrictive Transmission for Data Services in DS-CDMA Systems Jin W. Chang and Dan K. Sung Communication Networks Research Laboratory, Dept. of EE, Korea Advanced-42-869-3439, E-mail: dksung@ee.kaist.ac.kr or jwchang@cnr.kaist.ac.kr ABSTRACT A handoff control scheme for data
The purpose of this research contract was to design and analyze an optical multiple access system, based on Code Division Multiple Access (CDMA) techniques, for on board routing applications on a future communication satellite. The optical multiple access...
The concept of a fully meshed network of small personal communications terminals (PCTs) capable of avoiding undesirable double-hop delays for voice communications between these terminals is described. The satellite transponder bandwidth and satellite resources are shared on demand by all spread spectrum carriers via code-division multiple access (CDMA). ...
Spread spectrum modulation techniques such as frequency-hopped code division multiple access (FH-CDMA) are an efficient way to allow multi-user transmission over a limited bandwidth. Recently, there has been a push to increase user capacity over the same bandwidth. In particular, smart antenna arrays have been studied for their ...
This paper describes requirement for wireless transmission of Chaotic Code Division Multiplexed Access (Chaotic CDMA) and it focuses on real-time synchronization algorithm embedded into electronic programmable device. CDMA with quasi-orthogonal codes is used to allow multi-users to transmit simultaneously in the ...
. An enhanced DQRUMA/MC-CDMA protocol using minislots for request accesses is proposed to reduce request collisions. In the proposed protocol, request attempts are transmitted concurrently with data packets request accesses. The performance of the proposed protocol is evaluated by simulation and its result shows
Against the backdrop of the explosive expansion of the Internet and the continued dramatic increase in demand for high-speed multimedia wireless services, there is an urgent demand for flexible, bandwidth-efficient transceivers. Multistandard operation is also an important requirement for the future generations of wireless systems. This article presents a versatile broadband multiple ...
The propagation of optical Code Division Multiple Access (CDMA) signals was studied by computer simulation. Group velocity dispersion produces the worst impairment. With dispersion management, the decoder successfully recovers the signals, even in the presence of severe multi-access interference.
In unslotted frequency-hopped (FH) code-division multiple-access (CDMA) systems, a number of users can simultaneously transmit their packets by using quasi-orthogonal FH patterns (codes). The number of interfering users varies throughout the packet durati...
This paper presents the current stage of an IP-based architecture for heterogeneous environments, covering UMTS-like W-CDMA wireless access technology, wireless and wired LANs, that is being developed under the aegis of the IST Moby Dick project. This architecture treats all transmission capabilities as basic physical and data-link ...
This paper introduces an incorporated spectral-amplitude coding (SAC) optical code-division multiple-access (OCDMA) scheme. One novel class of optical signature codes based on combinatorial designs is employed with M-ary pulse-position modulation (PPM) signaling to improve the system performance beyond the interference limit. A union upper bound on the bit error rate (BER) is ...
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 ...
The OF (occurrence frequency) of CCLs (cross-correlation levels) is introduced to objectively judge CDMA (code division multiple access) code sets. Four-CCL and 5-CCL codes possessing more ideal OFs of CCLs than Gold code are presented. A new technique utilizing a multivariable Bernoulli process to model the outputs of a CDMA receiver ...
In this letter, we derive an exact bit error rate (BER) expression for downlink multi-carrier code division multiple access (MC-CDMA) systems with orthogonal restoring combining (ORC) in Nakagami-m fading channel. A simple approximated expression is also provided. For uncoded and coded MC-CDMA systems, the BER expressions are ...
In military radio communication systems it is important to transmit with as low power as possible to avoid detection by the hostile signal intelligence, and still obtain sufficient transmission quality. This thesis develops a distributed power control pro...
Mouse C3H 10T1/2 fibroblasts and human glioblastoma U87MG cells were exposed to cellular phone communication frequency radiations to investigate whether such exposure produces DNA damage in in vitro cultures. Two types of frequency modulations were studied: frequency-modulated continuous-wave (FMCW), with a carrier frequency of 835.62 MHz, and code-division multiple-access ...
This paper proposes adaptive transmit window control based on both location of mobile stations and traffic load for channel state based packet transmissions in CDMA cellular downlink communications. The proposed scheme constrains downlink packet transmissions by employing a transmit window individually given to each mobile station. The ...
The analysis of both performance and capacity of direct sequence CDMA in terrestrial cellular systems has been addressed in the technical literature. It has been suggested that CDMA be used as a multiple access method for satellite systems as well, in particular for multispot beam Low Earth Orbit Satellites (LEOS). One is tempted to ...
May 31, 2011... and the advanced wideband Direct Sequence - Code Division Multiple Access ( DS-CDMA) conceptual systems utilizing phased-array technology ...
NASA Website
For future mobile radio systems, an appropriately chosen multiple access technique is a critical issue. Multiple access techniques presently under discussion are code division multiple access (CDMA), time division multiple access (TDMA), and hybrids of both. In this paper, a hybrid C/TDMA ...
An integrated medium access control framework for a direct sequence code-division multiple access (CDMA) radio access to an asynchronous transfer mode (ATM) network is considered. The system accommodates multimedia services such as voice and data. The inherently high error rate associated with the multipath fading ...
This thesis examines a circular adaptive antenna array used at the mobile station for a typical Direct Sequence Code Division Multiple Access (DS- CDMA) cellular mobile communications system. The primary objective is to reduce co-channel interference of a...
Low probability of intercept (LPI) performance of a direct-sequence code division multiple access (DS-CDMA) system is investigated in this paper; both chaotic and pseudo-random binary spreading sequences are considered. Several intercept receiver structur...
Multicarrier code-division multiple access (MC-CDMA) system with adaptive frequency hopping (AFH) has attracted attention of researchers due to its excellent spectral efficiency. A suboptimal water-filling (WF) channel allocation algorithm was previously ...
of the received signal power level is shown in Fig. 1. The CDMA soft-handoff region in hexagonal cells with radius830 IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY, VOL. 47, NO. 3, AUGUST 1998 Effect of Soft Abstract-- The effect of soft and softer handoffs on code- division multiple-access (CDMA) system capacity
We present a novel multiple access scheme for Passive Optical Networks (PON) based on optical Code Division Multiple Access (OCDMA). Di erent from existing proposals for implementing OCDMA, we replaced the predominating orthogonal or weakly correlated signature codes (e.g. Walsh-Hadamard codes (WHC)) by convolutional codes. Thus CDMA ...
A digital image-watermarking algorithm based on fractional Fourier transform (FRFT) domain is presented by utilizing chaotic CDMA technique in this paper. As a popular and typical transmission technique, CDMA has many advantages such as privacy, anti-jamming and low power spectral density, which can provide robustness against image ...
The original DQRUMA/MC-CDMA protocol may suffer severe code collisions due to a limited number of request codes. An enhanced DQRUMA/MC-CDMA protocol using minislots for request accesses is proposed to reduce request collisions. In the proposed protocol, request attempts are transmitted concurrently with data packets of other calls. A ...
Remote teleconsultation by specialists is important for timely, correct, and specialized emergency surgical and medical decision making. In this paper, we designed a new personal digital assistant (PDA)-phone-based emergency teleradiology system by combining cellular communication with Bluetooth-interfaced local wireless links. The mobility and portability resulting from the use of PDAs and ...
In this paper, we propose a scheme for the optimal allocation of power, source coding rate, and channel coding rate for each of the nodes of a wireless Direct Sequence Code Division Multiple Access (DS-CDMA) visual sensor network. The optimization is quality-driven, i.e. the received quality of the video that is transmitted by the nodes is optimized. The ...
We investigate the problem of joint transmitter and receiver power allocation with the minimax mean square error (MSE) criterion for uplink transmissions in a multi-carrier code division multiple access (MC-CDMA) system. The objective of power allocation is to minimize the maximum MSE among all users each of which has limited transmit ...
A new method for developing optical code division multiplexed access (CDMA) address code sequences is presented. The method is based on the genetic algorithm, which has already shown success in developing 2D correlation functions for pattern recognition. The algorithm is very flexible in its optimization criteria and is thus adequate for various optical ...
A general constraint common to many wireless networks lies in the short lifetime of mobile terminal batteries. Energy efficient protocols that adapt to terminal battery power level can be used to reduce the effects of this limitation. This paper addresses such power-adaptive algorithms in medium access control (MAC) protocols and in the power control mechanisms for hybrid ...
In some multi-user radio systems the receiver is not allowed to transmit feedback information to the senders. In other applications the transmitters cannot receive feedback information sent by the receiver. For these cases a multiple access protocol is ne...
The integration of land, sea, and air forces within the littoral environment will require fading resistant, high data rate, non-exploitable communications. The large volumes of video and data information, i.e. Internet access, video teleconferencing and d...
A Satellite Mobile Communication. System Based on Band-Limited. Quasi- Synchronous. Code Division. Multiple Access (BLQS-CDMA). Abstract. R. De Gaudenzi, ...
The atmospheric two-dimensional optical code-division multiple-access (CDMA) systems using pulse-position modulation (PPM) and Turbo-coded were presented. We analyzed the bit-error rate (BER) of the proposed system using pulse-position modulation (PPM) with considering the effects of the scintillation, avalanche photodiode noise, thermal noise, and ...
In this paper, we derive optimal admission policies for integrated voice and data traffic in packet radio networks employing code division multiple access (CDMA) with direct-sequence spread spectrum (DS/SS) signaling. The network performance is measured in terms of the average blocking probability of voice calls and the average delay and packet loss ...
Optical code-division multiple access (OCDMA) is an interesting subject of research because of its potential to support asynchronous, bursty communications. OCDMA has been investigated for local area networks, access networks, and, more recently, as a packet label for emerging networks. Two-dimensional (2-D) OCDMA codes are preferred in current research ...
... Accession Number : AD0670798. Title : CENTRAL CHOLINERGIC TRANSMISSION: BEHAVIORAL ASPECTS OF CHOLINERGIC TRANSMISSION. ...
In this paper, performance of different MultiUser Detection (MUD) receivers are investigated for a MultiCarrier (MC)-Code Division Multiple Access (CDMA) system in an Indoor Wireless Local Area Network (WLAN). Simulation results show that benefits of MC-CDMA schemes in terms of capacity, throughput and Bit Error Rate (BER), are ...
Abstract � A novel approach to Multiuser Transmission (MUT) for the CDMA downlink in frequency-selective channels is proposed. The key idea is to minimize the BER at the receivers directly by pre-distortion of the transmitted symbols. The BER can be predicted in the transmitter by calculating the signal at the receiver (including interference) exactly ...
CDMA (code division multiple access) may be an attractive technique for wireless access to broadband services because of its multiple access simplicity and other appealing features. In order to investigate traffic handling capabilities of a future network providing a variety of integrated services, this paper ...
Due to the computational complexity of the optimum maximum likelihood detector (OMD) growing exponentially with the number of users, suboptimum techniques have received significant attention. We have proposed the particle swarm optimization (PSO) for the multiuser detection (MUD) in asynchronous multicarrier code division multiple access (MC-CDMA) system. ...
This letter presents low-complexity digital pulse shaping filter structures of a direct sequence code division multiple access (DS-CDMA) ultra wide-band (UWB) modem transmitter with a ternary spreading code. The proposed finite impulse response (FIR) filter structures using a look-up table (LUT) have the effect of saving the amount of memory by about 50% ...
A novel wideband beamforming technique for cellular CDMA systems is presented. The proposed algorithm asymptotically provides the optimum combination of space-time samples for maximizing the SINR for the Signal with the Desired Code (SDC) by canceling strong Multi-User Access Interference (MUAI) and optimally combining the multipath. In contrast to ...
We propose in this work, a simple method to calculate the bit error rate (BER) performance of a direct sequence code division multiple access (DS/CDMA) system over a Rayleigh multipath fading with power control error for both coherent and noncoherent reception, the RAKE structure receivers under consideration employ despreading sequences weighted (WDS) by ...
This proceedings of the 1999 conference of the Pacific Telecommunications Council contains 134 papers divided into the following topical areas: (1) Internet, including business developments, telephony, commerce, country developments in the Asia-Pacific region, Internet deployment, and Internetworking technology; (2) policy/regulatory, including country studies, competition, and broadcast; (3) ...
ERIC Educational Resources Information Center
In the downlink of WCDMA systems, the different users are multiplexed synchronously to transmission channel by short orthogonal spreading codes that user specific and a long overlay scrambling code that is base-station specific. It is well known that in a multiple-user synchronous DS-CDMA system with multi-path fading, the widely used rake receiver is ...
: In CDMA systems combining of several traffic channels leads to a multi-code (MC) CDMA system offering higher user data rates without increasing the system bandwidth. Due to imperfect spreading sequences, the transmission quality degrades in case of multipath propagation. The additional noise power caused by co-channel interference ...
This paper focuses on a CDMA design study for future third-generation mobile and personal communication systems such as FPLMTS and UMTS. In the design study, a rigorous top down approach is adopted starting from the most essential objectives and requirements of universal third-generation mobile systems. Emphasis is laid on high flexibility with respect to the implementation of ...
Two multiple-access signaling techniques of current interest for mobile communications are broadband code-division multiple-access (CDMA) and narrowband time-division multiple-access (TDMA). This project examined the relationship between signal design and...
To decrease total system cost and improve efficiency, in future mobile communication systems, we can implement a structure of multiple cells covering an area. This is often referred to as a Hierarchical Cell Structure, HCS. We compare five methods of sharing the scarce radio resources in a two layer HCS: I) DS-CDMA in macro cells and TDMA in micro cells, II) TDMA in macro ...
A minimum variance space-time (MVST) receiver with an antenna array has recently been proposed as a relatively simple method for designing blind multiuser receivers for code division multiple access (CDMA) systems. For time-varying CDMA systems, it is necessary to update the response vector, which is used to construct the receiver ...
We investigate the detection dynamics of the parallel interference canceller (PIC) for code-division multiple-access (CDMA) multiuser detection, applied to a randomly spread, fully synchronous base-band uncoded CDMA channel model with additive white Gaussian noise (AWGN) under perfect power control in the large-system limit. It is ...
In this paper we consider a CDMA system with error-control coding. Optimal joint decoding is prohibitively complex. Instead, we propose a sequential approach for handling multiple-access interference and error-control decoding. Error-control decoding is implemented via single-user soft-input decoders utilizing metrics generated by linear algebraic ...
The current goal is to create a set of portable terminals with GPS/BD2 dual-mode satellite positioning, vital signs monitoring and wireless transmission functions. The terminal depends on an ARM processor to collect and combine data related to vital signs and GPS/BD2 location information, and sends the message to headquarters through the military CDMA ...
Compressed video bitstream transmissions over wireless networks are addressed in this work. We first consider error control and power allocation for transmitting wireless video over CDMA networks in conjunction with multiuser detection. We map a layered video bitstream to several CDMA fading channels and inject multiple source/parity ...
A multiple-user interference reduction technique is proposed for optical code-division multiple-access (CDMA) systems. Data symbols from each user are encoded using a pulse-position modulation (PPM) scheme before multiplexing. Modified prime sequences are adopted as the signature codes in the multiplexing process. An interesting property of this code is ...
currently connected to the BS or the arrival rate #12;Frame ranging contention period e > T (1) (2) (3 Multiple Access (CDMA) ranging code during a contention period after synchroniz- ing with a base station ranging contention period. Second, we attempt to have the BS process ranging requests from emergency MSs
... of topological and system state data by a portion of the users. Such transmissions are accommodated by the existing transmission channels, and ...
... Accession Number : AD0628988. Title : DATA TRANSMISSION INVESTIGATION (SHORT RANGE HF RADIO DATA TRANSMISSION). ...
... Accession Number : AD0652098. Title : DATA TRANSMISSION - DIVISION ECHELON, DATA TRANSMISSION TEST NUMBER SEVEN. ...
... Accession Number : AD0610954. Title : TRANSMISSION OF MICROPULSATIONS THROUGH THE LOWER IONOSPHERE. ...
... Accession Number : AD0708629. Title : TRANSMISSION ELECTRON MICROSCOPY OF SODIUM CHLORIDE,. Corporate ...
... Accession Number : AD0255521. Title : TRANSMISSION DEVICE FOR REVERSIBILITY OF ROTATION WITH EXTREMELY FAST ACTION. ...
... Accession Number : AD0631324. Title : TRANSMISSION AND MECHANIZATION ASPECTS OF RESIDUE CODED SIGNALS. ...
... Accession Number : AD0149145. Title : TRANSMISSION AND EPIDEMIOLOGY OF TOXOPLASMOSIS. Descriptive Note : Final rept. ...
... Accession Number : AD0410859. Title : THE TRANSMISSION OF STRESS WAVES AT AN INTERFACE SEPARATING LIQUID AND VOIGT SOLID,. ...
... Accession Number : AD0622576. Title : THE TRANSMISSION OF LIGHT BY CRYSTAL AGGREGATES BETWEEN POLARIZERS II. ...
... Accession Number : AD0670625. Title : THE TRANSMISSION OF GEOMAGNETIC DISTURBANCES. Descriptive Note : Final rept. ...
... Accession Number : AD0831561. Title : TABULATION OF DOSE TRANSMISSION FACTORS FOR HOMOGENEOUS SLABS,. ...
... Accession Number : AD0413741. Title : NONUNIFORM TRANSMISSION LINES. Corporate Author : LIBRARY OF CONGRESS ...
... Accession Number : AD0407089. Title : NONLINEAR TRANSMISSION CHARACTERISTICS OF THE PLASMA SHEATH. ...
... Accession Number : AD0075479. Title : LIGHT TRANSMISSION AND HAZE REQUIREMENTS FOR TRANSPARENT ENCLOSURES. ...
... Accession Number : ADP006888. Title : Emissivity and Transmissivity of a Randomly Laminar Structure,. Corporate Author ...
... Accession Number : ADA022858. Title : Component Development for Transmission and Correlative Reception of Artificial Atmospherics. ...
... Accession Number : AD0758348. Title : Automobile Transmission Oil,. Corporate Author : FOREIGN TECHNOLOGY DIV ...
... Accession Number : AD0628676. Title : ANALYSIS AND TEST OF SIGNAL TRANSMISSION IN A MULTIPHASE FLUID MIXTURE. ...
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A simple exact error rate analysis is presented for random binary direct sequence code division multiple access (DS-CDMA) considering a general pulse shape and flat Nakagami fading channel. First of all, a simple model is developed for the multiple access interference (MAI). Based on this, a simple exact expression of the ...
in the entire network. The power decays in distance r in accordance with )1/( )( 0 0 + = rr P rP (1) where P0 is the transmission power, r0 > 0 is a scaling constant for distance, and > 2. The power decay law satisfies two physical observations. That is, the received power decays exponentially in distance with the exponent
U transmission antennas are scrambled using the kth user's pseudo-noise (PN) sequence PNk(t), in or- der the same order of importance. I. INTRODUCTION The capacity and the achievable data rate of wireless commu are shown in Fig.1, where real-valued data symbols using BPSK modulation and real-valued spreading [5] were
in the presence of narrowband interference (NBI) [l]. The bit error probability of the FD-MUD is derived over fading channel. It is also shown that the FD-MUD has robustness to NBI. In addition, advantages of the FD density (psd) N& and i(t) is the NBI with the transmission bandwidth BW, and the total power I
are exponentially distributed with parameter �. Then, assuming a fixed slow down rate a, the load (and thereby derivation of the blocking probabilities. However, slowing down the transmission rates in all system states to class-k 1/�(k) Mean (nominal) holding time of sessions belonging to class-k ^a(k) Maximum slow down
arrives, the frame might be already displayed. FEC can be used in these cases. We use Bose control using re� transmission was done for audio packets [3]. They show that by adding some delay before playing the audio, audio data can be protected from packet loss. Retransmission and error con� cealment
to tolerate co-channel transmissions, but avoid them by either scheduling (NB) or hopping (FH). DS-CDMA can detection techniques, since only nearby (strong) interferers can be cancelled. In DS systems, it is nearly impossible to acquire their signals. Therefore, they cannot be cancelled. Successive interference
Page 1. Multiuser Detectors for MIMO DS/CDMA Systems ... We consider a DS/CDMA communication system with K active users. ...
Abstract�In the present paper, a call admission control scheme that can learn from the network environment and user behavior is developed for code division multiple access (CDMA) cellular networks that handle both voice and data services. The idea is built upon a novel learning control architecture with only a single module instead of two or three ...
We consider the problem of joint multi-user detection and channel parameter estimation in a space-time bit-interleaved coded modulation (ST-BICM) scheme for an asynchronous DS-CDMA uplink transmission over frequency selective channels. The performance of standard coherent detectors relies on the availability of accurate estimates of the channel parameters ...
Universal Mobile Telecommunications System (UMTS) wireless technologies is a proposed standardization as a part of 3GPP solutions to satisfy IMT-2000 requirements. It is based on wideband CDMA technology. It will provide full coverage and mobility for 144 Kb/s, preferably 384 Kb/s and limited coverage and mobility for 2 Mb/s. It proposes high spectrum efficiency compared to ...
The advanced technology of computing system was followed by the rapid improvement of medical instrumentation and patient record management system. The typical examples are hospital information system (HIS) and picture archiving and communication system (PACS), which computerized the management procedure of medical records and images in hospital. Because these systems were built and used in ...
A link throughput-delay analysis is presented for a slotted direct-sequence spread-spectrum multiple-access packet radio network (PRN) operating in the presence of background noise, multiple-access interference, and pulsed jammer noise. The PRN is comprised of an arbitrary number of full-duplex radio units arranged in a paired-off topology. Slotted ALOHA ...
In mobile communication systems, high speed packet data services are demanded. In the high speed data transmission, throughput degrades severely due to severe inter-path interference (IPI). Recently, we proposed a random transmit power control (TPC) to increase the uplink throughput of DS-CDMA packet mobile communications. In this paper, we apply IPI ...
We consider a common architecture for wireless voice and data communication of multimedia services using ATM over a Rayleigh fading CDMA channel, and propose a CDMA packet frame structure with two dimensional error detection. The high error rate associated with radio transmission is overcome by introducing a data link control layer in ...
In this paper we present the design concept plus experimental results and evaluation of a newly developed advanced DWDM Radio-on-Free-Space Optical (RoFSO) communication system capable of simultaneous transmission of multiple RF signals. The RoFSO system is evaluated based on the performance metric parameters defined for the various RF signals comprising of different wireless ...
