code division multiple access cdma

... Trang 370 CODE DIVISION MULTIPLE ACCESS (CDMA)10 − 3 10 − 2 10 − 1 10 0 Users Upper bound Lower bound Simulated FIGURE 2.33: System performance for FHMA system with random hopping codes (100 ... number of channels available is the same as in FDMA Trang 1178 CODE DIVISION MULTIPLE ACCESS (CDMA)One of the primary advantages of CDMA systems is universal frequency reuse That is, since the ... Trang 168 CODE DIVISION MULTIPLE ACCESS (CDMA)10 -6 10 -5 10 -4 10 -3 10 -2 10 -1 Eb/No (dB) No diversity Diversity order

Ngày tải lên: 07/08/2014, 21:20

... common code, Node 2 is transmitting on Code 2, Node 4 is transmitting on Code 4, and Node 7 is transmitting on the common code Node 3 is listening on Code 4, and Node 6 is listening on Code 2 ... brings with it the possibility of multiple channels since multiple spreading codes are possible With multiple channels, we now must determine which channels (i.e., codes) the receiver should monitor ... decoded frames sent to the mobile switching center However, softer hand-off typically fails to provide the same diversity advantage as soft hand-off Trang 2CELLULAR CODE DIVISION MULTIPLE ACCESS

Ngày tải lên: 07/08/2014, 21:20

... limiting factor in the capacity of CDMA systems As a result, capacities for single-cell CDMA systems can be substantially lower than those fororthogonal multiple access techniques such as TDMA or ... previous chapters, the conventional matched filter receiver treats multiple accessinterference (MAI), which is inherent in CDMA, as if it were additive noise because, afterdespreading, the MAI ... random spreading codes We arbitrarily examine the output of a filter matched to the kth user’s spreading waveform during the first bit interval (assuming perfect carrier and PN code phase tracking)

Ngày tải lên: 07/08/2014, 21:20

... 17:14 CODE DIVISION MULTIPLE ACCESS (CDMA) [14] F A Tobagi and L Kleinrock, “Packet switching in radio channels: Part III—Polling and (dynamic) split-channel reservation multiple access, ... C Wu and V O K Li, “Receiver-initiated busy-tone multiple access in packet radio networks,”... synchronous code- division multiple- access channel,” IEEE Transactions on Communications, ... T1: IML September 28, 2006 17:14 CODE DIVISION MULTIPLE ACCESS (CDMA) [69] Z Zvonar and D Brady, “Suboptimum multiuser detector for synchronous CDMA frequency-selective Rayleigh fading

Ngày tải lên: 07/08/2014, 21:20

... Chương 1: Giới thiệu 1.1 Công nghệ WCDMA và tình trạng triển khai WCDMA(wideband code division multiple access) là chuẩn liên lạc 3G song hành cùng với chuẩn GSM WCDMA là công nghệ nền tảng cho các ... công nhận WCDMA là giao diện nền tảng cho UMTS FOMA được NTT Docomo đưa vào ứng dụng từ năm 2001 và được coi là dịch vụ 3G thương mại đầu tiên trên thế giới.Mặc dù cũng dựa vào nền tảng WCDMA song ... nghệ và được phát triển trên cơ sở của hệ thống 3G W-CDMA HSDPA có tốc độ truyền tải dữ liệu lên tối đa gấp 5 lần so với khi sử dụng công nghệ CDMA Về mặt lý thuyết, HSDPA có thể đạt tốc độ truyền

Ngày tải lên: 02/06/2015, 17:26

... Spread-spectrum multiple access is a popular technique al-lowing several users to share the same bandwidth at the same time Spread spectrum is often equated with direct-sequence codivision multiple access ... Nevertheless, the interleaved code symbols can be transmit-ted at a rate up to 1/R times higher than the info bit rate, whereR is the code rate of the encoder Therefore the terms code symbol and chip ... (1/R, 1) code with ran-dom code bits is used throughout this paper, that is, every info bit is mapped to a random binary sequence of length 1/R This code is equivalent to a repetition code with

Ngày tải lên: 22/06/2014, 23:20

... MIMO multiple input multiple output BEM basis expansion model ML maximum likelihood BER bit error rate MMSE minimum mean square error BS base station MS mobile station CDMA code division multiple ... division multiple access MSE mean square error CFO carrier frequency offset OFDM orthogonal frequency division multiplexing CP cyclic prefix OFDMA orthogonal frequency division multiple access CRLB ... parallel to sequential FDMA frequency division multiple access QPSK quaternary phase shift keying FFT fast Fourier transform SDMA space division multiple access IBI inter-block interference SB

Ngày tải lên: 14/09/2015, 14:03

... regarding the traffic on the stability performance of Gaussian multiple-access channels We will focus our attention on a slotted Gaussian multiple-access channel withK users sending bursty data to a single ... capacity A ((2nR1, 2nR2, , 2 nR K),n) code for multiple-access channel consists ofK encoding functions f i:Wi → X n i where Wiis the input to the encoder at useri and takes 2 nR ivalues, and ... the ensemble of i.i.d random codes Specifically, each user generates a codebookC(i)containing 2nR i = SNR r i n i codewords denoted as X(1i), , X(SNR i) rin i Each codeword isn-length vector

Ngày tải lên: 21/06/2014, 23:20

... strategies (i) Regenerative decode-and-forward (RDF) The relay decodes the messagew i, re-encodes it using the same code book as the source node, and transmits the codeword to the destination ... (ii) Nonregenerative decode-and-forward (NDF) The relay decodes the messagew i, re-encodes it using a different code book from that used by the source node, and transmits the codeword to the destination ... multiple access relay (MAR) systems in order to maximize the achievable rate region Four relaying strategies are considered; namely, regenerative decode-and-forward (RDF), nonregenerative decode-and-forward

Ngày tải lên: 22/06/2014, 01:20

... to a single receiver Each user is LDPC encoded by different irregular LDPC codes (the LDPC codes could however belong to the same code ensemble) with code-word length N, and their respective received ... H Liao, Multiple access channels, Ph.D thesis, University of Hawaii, Honolulu, Hawaii, USA, 1972 [4] R Palanki, A Khandekar, and R McEliece, “Graph based codes for synchronous multiple access ... address the problem of designing good LDPC codes for the Gaussian multiple access channel (MAC) The framework we choose is to design multiuser LDPC codes with joint belief propagation decoding

Ngày tải lên: 22/06/2014, 19:20

... Cross-Layer Design of an Energy-Efficient Cluster Formation Algorithm with Carrier-Sensing Multiple Access for Wireless Sensor Networks Chiara Buratti IEIIT-BO/CNR, DEIS, University of Bologna ... periodically triggers the WSN, and nodes uniformly distributed over a specified area Rout-ing, multiple access control (MAC), physical, energy, and propagation aspects are jointly taken into account ... appendix Information routing is based on a clustered self-organized structure; a carrier-sensing multiple access (CSMA) protocol is chosen at MAC layer Two different scenarios are examined, characterized

Ngày tải lên: 23/06/2014, 00:20

... virtual multiple-input-multiple-output (MIMO) system, which can also be viewed as a space-division-multiple-access (SDMA) system Note that due to the analogy between the direct-sequence code-division-multiple-access ... transtrans-missions re-sult in failure), the throughput of the multiple access net-work is limited: the maximum throughput per slot is 1 for time-division-multiple-access (TDMA), and is only 1/e for slotted-ALOHA ... between the direct-sequence code-division-multiple-access (DS-CDMA) system and the MIMO system, the analysis in this paper can also be adapted to the DS-CDMA system with a single receive an-tenna

Ngày tải lên: 23/06/2014, 00:20

... communication CCU Wireless Access Tech Lab Wireless Access Tech Lab Introduction (4) CCU Wireless Access Tech Lab Wireless Access Tech Lab Frequency Division Multiple Access (FDMA) (1) Each transmitter ... Wireless Access Tech Lab Wireless Access Tech Lab Frequency Division Multiple Access (FDMA) (2) Allocation of separate channels to FDMA signals CCU Wireless Access Tech Lab Wireless Access Tech ... Multiple Access Techniques for Wireless Communications 2005/07/06 Weng Chien-Erh Wireless Access Tech Lab Table of Contents(1) Introduction FDMA TDMA CDMA SS (Spread Spectrum)

Ngày tải lên: 11/07/2014, 21:20

... Trang 1Carrier Sense Multiple Access with Collision AvoidanceCarrier Sense Multiple Access with Collision Avoidance Trang 21 Basic CSMA/CA operation 2 Wireless medium access example 3 Usage ... Trang 22Wireless medium access (2)”winner” and starts sending packet 3 4 AC K 2 Wireless medium access example Trang 23Wireless medium access (3)DIFS 5 AC K 2 Wireless medium access example Trang ... medium access (1)Contentio n Window Backoff 1) While station A is sending a packet, stations B and C also wish to send packets, but have to wait (defer + backoff) AC K 2 Wireless medium access

Ngày tải lên: 06/10/2014, 21:38

... ULTRA-WIDEBAND MULTIPLE ACCESS SYSTEMS CAO WEI NATIONAL UNIVERSITY OF SINGAPORE 2007 EXACT BER ANALYSIS AND DESIGN OF PRERAKE COMBINING SCHEMES FOR DIRECT SEQUENCE ULTRA-WIDEBAND MULTIPLE ACCESS ... DS UWB multiple access systems. The second one is to effectively capture energy using Prerake combining schemes. Although the Gaussian approximation (GA) on the distribution of multiple access ... for multiple access communications using antipodal signaling,” in IEEE International Conference on Communications, May 2003, pp. 2197–2201. [7] ——, “Performance analysis of DS-UWB multiple access

Ngày tải lên: 12/09/2015, 11:00

... Rate Computation of TH-PPM UWB Multiple Access Systems”, Proc Of PIMRC 2004, September 2004 [4] S Niranjayan, A Nallanathan and B Kannan, “Exact Modeling of Multiple Access Interference and BER ... [5] S Niranjayan, A Nallanathan and B Kannan, “Modeling of Multiple Access Interference and BER Derivation for TH and DS UWB Multiple Access Systems”, IEEE Transactions on Wireless communications, ... mono-pulses, where the multiple access technique can be time hopping (TH) or direct sequence (DS) And, different modulation techniques like PPM, PAM and OOK can be equipped to encode the data on to

Ngày tải lên: 05/10/2015, 22:04

... PERFORMANCE OF MULTIPLE ACCESS MULTI-CARRIER MULTILEVEL FREQUENCY SHIFT KEYING SYSTEMS TAY HAN SIONG NATIONAL UNIVERSITY OF SINGAPORE 2005 Trang 2OPTIMIZING PERFORMANCE OF MULTIPLE ACCESS MULTI-CARRIER ... MC-MFSK systems transmit on multiple frequency carriers simultaneously The system allows multiple-user access with its users sharing the same frequency and time space These multiple users are differentiated ... novel method of selecting the multiple sub-channels used by all users for symbol transmission The selection of sub-channels improves the error performance of the multiple-access MC-MFSK system by

Ngày tải lên: 27/11/2015, 12:32