wideband code division multiple access คือ

Ngày tải lên: 27/06/2014, 14:20

... 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

Ngày tải lên: 22/06/2014, 23:20

Ngày tải lên: 23/06/2014, 01:20

... Standards 46 2.6 Summary 48 3 Multiple Access in Cellular Communication Systems 49 3.1 Multiple Access and the OSI Layers 49 3.2 Basic Multiple Access Schemes 53 3.3 Medium Access Control in 2G Cellular ... individual portions of its resources to support multiple communications, basic multiple access techniques (such as frequency-, time-, or code- division multiple access, with FDMA, TDMA, and CDMA as their ... with multiple access protocols,which govern access to these resources. The basic multiple access schemes are briefly described further below in this section, and the importance of the multiple access...

Ngày tải lên: 02/03/2013, 16:59

... Outgoing access list is ________ Inbound access list is ________ Interface __________ Outgoing access list is ________ Inbound access list is ________ Interface __________ Outgoing access ... Verify the Access Lists a. Now that the access lists have been applied, they need to be verified. First, verify what lists have been defined. From a CLI session on one of the routers with access ... of the routers with access lists, display the access lists with the Boaz#show ip access- lists command. Record the information about one of the access lists. _____________________________________________________________________________________...

Ngày tải lên: 18/01/2014, 05:20

... polling access method 12.40 Figure 12.22 Time -division multiple access (TDMA) 12.35 Figure 12.20 Logical ring and physical topology in token-passing access method 12.1 Chapter 12 Multiple Access Copyright ... protocol 12.24 Figure 12.13 Collision and abortion in CSMA/CD 12.38 Figure 12.21 Frequency -division multiple access (FDMA) 12.29 In CSMA/CA, the IFS can also be used to define the priority of a station ... rule and examples of creating Walsh tables 12.43 Figure 12.23 Simple idea of communication with code 12.10 A pure ALOHA network transmits 200-bit frames on a shared channel of 200 kbps. What...

Ngày tải lên: 16/02/2014, 20:20

... cyclic redundancy check (CRC) codes with generation polynomial G(x) = x 4 +x+1, as an example of the coded transmission. The codebook is denoted as C tc . For comparison, uncoded transmission is also ... various codes such as natural binary codes to represent the quantized observations. In this paper, our focus is to design decentralized estimators; therefore, we will not address the transmission codebook ... estimation for a deterministic parameter using digital communications over orthogonal multiple- access fading channels with a multiple- bit quantizer. By introducing a general messaging function, the proposed...

Ngày tải lên: 18/06/2014, 22:20

... (2008) 28 which codebook is denoted as C tn . We consider BPSK modulati on for all codebooks. Because the code length of the uncoded transmission is shorter than that of the coded transmission, ... cyclic redundancy check (CRC) codes with generation polynomial G(x) = x 4 +x+1, as an example of the coded transmission. The codebook is denoted as C tc . For comparison, uncoded transmission is also ... for example, when the natural binary code and BPSK are applied to r e pr e s ent each quantized observation and to modulate. For any c m in such a transmission codebook, defined as C tn , there exists...

Ngày tải lên: 20/06/2014, 04:20

... the minimum distance of the BCH code. ). The encoded sequence at the output of the BCH encoder is next processed through an inner LDGM code, that is, a linear code with low density generator matrix ... coding of correlated senders over multiple access channels,” in Proceedings of the Allerton Conference on Communication, Control, and Computing, 2004. [39] A. Hocquenghem, “Codes correcteurs d’erreurs,” ... sequence {x n k } K k =1 to codeword {c n l } L l =1 through the LDGM parit y check matr ix H and the BCH code (to be later detailed), and the relationship between the received sequence {y l } L l =1 and the N codewords {c n l } L l =1 ,withn...

Ngày tải lên: 21/06/2014, 07:20

... analyzing the performance of wireless multiple access protocols. 8. Conclusion In this paper, we have introduced the notion of partial inter- ference in wireless multiple access systems and illustrated the ... impact of interference on multiple access networks, we propose an analytical framework to characterize partial interference for two representative types of multiple access wireless networks, ... demonstrate that it is important to model the partial interference effects while analyzing wireless multiple access networks. This is because such considerations can result in not only significant quantitative...

Ngày tải lên: 21/06/2014, 11:20

... article “Polarization Division Multiple Access With Polarization Modulation for LOS Wireless Communications” by Bin Cao, Qin-Yu Zhang, and Lin Jin discusses a potential multiple access and modulation ... frequency offset (CFO) estimation in the uplink of multiuser multiple- input multiple- output (MIMO) orthogonal frequency division multiplexing (OFDM) systems. Conventional maximum likelihood ... in Multiple Access Communications such as new cooperative MAC protocols; spectrum sharing, and channel assignment techniques for cognitive radio networks; new results on PHY layer multiple access...

Ngày tải lên: 21/06/2014, 17:20

... the capacity analysis given in Section 3 for a single user to be extended to a multiple- access system. 4.1. Multiple- access interference model Asgivenin(4), the received signal is modeled as r(t) = K  k=1 L  l=1 a lk (t)X (k) l  t ... active in the multiple- access system, the optimal PPM receiver has a complex structure that takes advantage of all receiver knowledge regarding the characteristics of the multiple- access interference ... Capacity of a multiple access UWB system with PAM over a multipath fading channel with L = 4, m = 0.65, K = 200, G = 100, and P x =−11 dBm. The instantaneous capacity for a multiple access UWB system...

Ngày tải lên: 21/06/2014, 22:20

... the code, and P e (d) is the PEP defined as the probability of decoding a received sequence as a weight-d codeword given that the all- zero codeword is transmitted. In (6), w d is the number of codewordswithoutputweightd ... spread-spectrum multiple- access communications over fading channels,” IEEE Transactions on Communications, vol. 30, no. 5, part 2, pp. 996–1009, 1982. [3] G. Einarsson, “Coding for a multiple- access frequency- hopping ... distance of the code. The resultant code rate after puncturing is given by  R c = mR c m −1 . (34) Ta bl e 1 shows the code rates and the minimum distances of the punctured codes for different...

Ngày tải lên: 21/06/2014, 23:20

... regarding the traffic on the stability performance of Gaussian multiple- access channels. We will focus our attention on a slotted Gaussian multiple- access channel with K users sending bursty data to a ... to the encoder at transmitter i can have any bit-sequence of length nγ i . These are encoded to 2 nγ i codewords of length n (sincewedonot know the whole statistical information,we encode only ... ensemble of i.i.d. random codes. Specifically, each user generates a codebook C (i) containing 2 nR i . = SNR r i n i codewords denoted as X (i) 1 , , X (i) SNR r i n i .Each codeword is n-length vector...

Ngày tải lên: 21/06/2014, 23:20

... strategies. (i) Regenerative decode-and-forward (RDF). The relay decodes the message w i , re-encodes it using the same code book as the source node, and transmits the codeword to the destination ... Nonregenerative decode-and-forward (NDF). The relay decodes the message w i , re-encodes it using a different code book from that used by the source node, and transmits the codeword to the destination ... allocation for orthogonal 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...

Ngày tải lên: 22/06/2014, 01:20

Ngày tải lên: 22/06/2014, 19:20

Ngày tải lên: 22/06/2014, 19:20

Ngày tải lên: 23/06/2014, 00:20

Ngày tải lên: 23/06/2014, 00:20