MULTIPLE ACCESS TECHNIQUES PPT FOROUZAN

Multiple Access Techniques for Wireless Communications2005/07/06Weng Chien-Erh Wireless Access Tech. Lab.CCU Wireless Access Tech. Lab.Table of Contents(1)IntroductionFDMATDMACDMASS (Spread Spectrum)FHSSDSSSHybrid Wireless Access Tech. Lab.CCU

CHAPTER TENMultiple-Access Techniques10.1 INTRODUCTIONThree commonly used techniques for accommodating multiple users in wirelesscommunications are frequency division multiple access (FDMA), time divisionmultiple access (TDMA), and code division mu[r]

use. Frequencies up to the millimetric band (about 60 GHz) are beinginvestigated. In these regions, large amounts of spectrum are availableto accommodate wideband modulation systems and the radio waveattenuation is significantly greater than the free-space loss whichhelps to define a very high capac[r]

P1: IML/FFX P2: IML/FFX QC: IML/FFX T1: IMLMOBK023-01 MOBK023-Buehrer.cls September 28, 2006 15:541CHAPTER 1Multiuser CommunicationsAll communication systems that support multiple users must have a set of protocols to allowthese multiple users to share a common access medium. Th[r]

carrier waves, and, as the name implies, bandwidths much wider than that required for simple point-to-point communication at the same data rate. Originallythere were two motivations: either to resist enemy efforts to jam the communications (anti-jam), or to hide the fact that communication was even[r]

frequency hopping technique uses frequency diversity. Of course, the hopping sequences2 The Mobile Radio Channel and the Cellular Principle16Figure 2.7: TDMA channels on multiple carrier frequenciesFigure 2.8: TDMA with use of frequency hopping techniquemust be orthogonal, i.e. one must ascer[r]

Hindawi Publishing CorporationEURASIP Journal on Wireless Communications and NetworkingVolume 2008, Article ID 378097, 9 pagesdoi:10.1155/2008/378097Research ArticleOther-Cell Inter ference Reducing Resource Allocation inOFDM-Based Asynchronous Cellular SystemsJin-Woo Lee, June Moon, and Yong-Hwan L[r]

Hindawi Publishing CorporationEURASIP Journal on Wireless Communications and NetworkingVolume 2006, Article ID 60585, Pages 1–9DOI 10.1155/WCN/2006/60585Joint MIMO-OFDM and MAC Design for BroadbandMultihop Ad Hoc NetworksDandan Wang and Uf TureliElectrical and Computer Eng ineering Department, Steve[r]

with the front and back file systems. Unlike Panache,it does not mimic the namespace of the remote file sys-tem and does not provide direct POSIX access to thecache. Moreover, FS-Cache is a single node system andis not designed for multiple nodes of a cluster accessingthe ca che concurre[r]

propriate may change during the knowledge discovery process. For instance, at some pointone may wish to redefine the data set on which models are evaluated (e.g. because it is foundthat it contains outliers that make the evaluation procedure inaccurate) and re-evaluate pre-viously built models. In (B[r]

7Traffic Considerations inComparing Access Techniquesfor WLLStefan Mangold, Ingo Forkel, Roger Easo and Bernhard Walke7.1 IntroductionThe focus of interest is the multiple access technology that will be employed in WirelessLocal Loop (WLL) systems, here referred to as Fixed Wire[r]

Keeping the average transmission power constant, we show that the TOA accuracy of each user does not depend on its transmissionprobability, while being a nondecreasing function of the transmission probability of any other user. Therefore, a generalized,noncontinuous CDMA system with a probability co[r]

per carrier; GSM: 200 kHz carrier, eight full-rate users per carrier) FDMA still fulfils arole in providing multiple access, although not down to individual channels. In 3G systemswith wideband carriers, on the other hand, it is predominantly used to assign parts of thetotal bandwidth a[r]

LNCTstatic641046441c) What do you deduce from?For multiplexing static, the average time of stay T is N times greater than if all theframes had been ordered, as in a single queue using the single channel globally. Thestatic solutions are simple to introduce, but suffer from a very low yield. Y[r]

1The Generalized CDMA1.1 IntroductionOne of the basic concepts in communication is the idea of allowing several transmittersto send information simultaneously over a communication channel. This concept isdescribed by the terms multiple access and multiplexing.Thetermmultiple access<[r]

hand, the capacity is not fixed but is limited by the interference between users. Such asystem is said to have a ‘soft’ capacity limit, since excess users may be allowed accessat the expense of increased interference to all users. In general, the capacity in Pseudo-Orthogonal (PO) or Asynchronous (A)[r]

Hybrid networks consisting of satellite links and mobile ad hoc networkspresent a series of challenges due to different packet-loss patterns, delay, and,usually, scarce available bandwidth. In this scenario, redundant encoding, inthe form of Forward Erasure Correction (FZC) codes [29],[30], can provi[r]

x(t −τ)dτ + b(t) (3)τ is the time delay.3. Diversity schemesThis section is intended to present methods for improving the reliability of communicationsystem by using different types of diversity.6MIMO Systems, Theory and Applications3.1 Spatial diversityThe use of multiple antennas in MIMO sy[r]