wideband code division multiple access คือ

... Now, with independent random hopping codes, the probability of at least one hit can be written as Trang 2SPREAD SPECTRUM TECHNIQUES FOR CODE DIVISION MULTIPLE ACCESS 69where P2is the probability ... 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 ... 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

... Detection As discussed in previous chapters, the conventional matched filter receiver treats multiple accessinterference (MAI), which is inherent in CDMA, as if it were additive noise because, ... capacities for single-cell CDMA systems can be substantially lower than those fororthogonal multiple access techniques such as TDMA or FDMA In addition, if one of thereceived signals is significantly ... 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, ... (5.95) P1: IML/FFX P2: IML MOBK023-05 MOBK023-Buehrer.cls September 28, 2006 15:56 166 CODE DIVISION MULTIPLE ACCESS (CDMA) where Z k,l,i,n is the vector of Walsh transform outputs for the lth path

Ngày tải lên: 07/08/2014, 21:20

... 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 ... (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 ... 10.1155/ASP/2006/81729 Iterative Pilot-Layer Aided Channel Estimation with Emphasis on Interleave-Division Multiple Access Systems Hendrik Schoeneich and Peter Adam Hoeher Information and Coding Theory Lab,

Ngày tải lên: 22/06/2014, 23:20

... acampora@ece.ucsd.edu Received 30 May 2003; Revised 5 February 2004 Space-division multiple-access (SDMA) systems that employ multiple antenna elements at the base station can provide much higher ... of multiple-access system with multiple antennas at the base station Most previous studies are constrained to either fixed channel condition [11,12] or ergodic capacity region [13] The space-division ... maximize the sum capacity of a time invariant Gaussian MIMO multiple-access channel The ergodic capacity region for MIMO multiple-access channel with covariance feedback has been studied in [13]

Ngày tải lên: 23/06/2014, 01:20

... 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 ... S/P sequential to parallel MAI multiple access interference TDMA time division multiple access MF matched filtering WiMAX worldwide interoperability microwave access viii Summary In current broadband

Ngày tải lên: 14/09/2015, 14:03

... 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 ... Jun 2003, pp. 229–233. [50] ——, “Ultra wideband impulse radio signal interference to code division multiple access system,” in IEEE International Symposium on Personal, Indoor and Mobile Radio

Ngày tải lên: 12/09/2015, 11:00

... 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 ... smaller to avoid the excessive multiple access interference Therefore, in ad-dition to the SDMA that defines the channelization in each slot, another level of medium access control is necessary

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 ... without interference from another CCU Wireless Access Tech Lab Wireless Access Tech Lab Introduction (2) CCU Wireless Access Tech Lab Wireless Access Tech Lab Introduction (3) In conventional

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

... 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

... advancements in the field of multiple access communications, with an emphasis on wireless sensor networks, physical layer techniques, resources handling and allocation, medium access control protocols, ... Carrier-Sense Multiple Access Protocols with Cooperative Diversity Ramiro Samano-Robles and Atilio Gameiro A Centralized Mechanism to Make Predictions Based on Data from Multiple ... hard-coded in the java classes and are not accessible from the GUI These parameters are not supposed to be modified by the user, as they are part of the different modules Table lists the hard-coded

Ngày tải lên: 04/03/2019, 11:46

... transmission. THEORY OF CODE DIVISION MULTIPLE ACCESS COMMUNICATION 1 INTRODUCTION TO CELLULAR MOBILE RADIO COMMUNICATION The subject of this book is code division multiple access (CDMA) communi- cations. ... during Theory of Code Division Multiple Access Communication, by Kamil Sh. Zigangirov ISBN 0-471-45712-4 Copyright  2004 Institute of Electrical and Electronics Engineers 1 THEORY OF CODE DIVISION MULTIPLE ... actually consists of two simplex channels. Frequency division multiple access (FDMA) and time division multiple access (TDMA) are the two major access techniques used to share the available band- width...

Ngày tải lên: 01/06/2014, 11:27