CDMA truy cập và chuyển mạch P10

... ‘Pseudo-Orthogonal’ CDMA 10.1 Overview The CDMA systems presented in the previous chapters were mainly based on the synchronous or orthogonal approach. As we have discussed, orthogonal CDMA achieves ... mobility environment. In such an enviroment, we use ‘Pseudo-Orthogonal’ (PO) CDMA. In the PO -CDMA, capacity (users /CDMA- band) is limited by interference resultingfrom the use of imperfectly orthogonal ... Multi-User Detection As we mentioned above, the capabilities of a pseudo-orthogonal or Asynchronous CDMA (A -CDMA) are limited by the near-far eﬀect, and in general by the Multiple Access Interference...

Tài liệu CDMA truy cập và chuyển mạch P1 pdf

... sequences. Then we have the conventional asynchronous CDMA, also called direct sequence CDMA (DS /CDMA) .The Orthogonal CDMA Orthogonal CDMA (O -CDMA) is based on binary orthogonal sequences of length ... The multiuser data communications process.GENERALIZED CDMA 3TDMAG-TDMA DS -CDMA G-PDMAG -CDMA FDMAG-FDMA FH -CDMA Figure 1.2 The G -CDMA as the super-set of the multiple access methods.Each ... and for multiplexing multiple symbolrates in orthogonal CDMA channels.28 CDMA: ACCESS AND SWITCHINGReferences[1] D. Gerakoulis ‘G -CDMA: a Unifying Approach to Multiple Access Com-munications’...

Tài liệu CDMA truy cập và chuyển mạch P2 pdf

... Theory, Vol. IT-20, May 1974, pp. 397–399.56 CDMA: ACCESS AND SWITCHING[7] X.D. Lin and K.H. Chang ‘Optimal PN Sequence Design for Quasisyn-chronous CDMA Communication System’ IEEE Trans. on Commun.,Vol. ... z1· z2···zkThe orthogonal matrices Hzcan be constructed by any method described above.40 CDMA: ACCESS AND SWITCHINGFigure 2.4 Fourier, Hadamard and Karhunen–Loeve orthogonal codes of size-16.SPREADING ... W∗denotes the Hermitian conjugate (transpose, complex conjugate) and I is the unitmatrix.42 CDMA: ACCESS AND SWITCHING−−−−−−−−−−−−=43454345474347447454745434434474434543454744344745474543411111111111111118ππππππππππππππππππππππππππππππjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjeejeejeejeejeejeejeejeejeejeejeejeejeeeejeejeHFigure...

Tài liệu CDMA truy cập và chuyển mạch P3 pptx

... satellite switched CDMA (SS /CDMA) B. The base station switched CDMA (BS /CDMA) CDMA ExchangeNodeH/EH/EH/EH/EPSTNCoax-cable NetworkC. The cable switched CDMA (CS /CDMA) H/E:Head-EndPSTN: ... Systems.‘S- CDMA as a High-Capacity Upstream Physical Layer’ IEEE802.14a/98-016,June 15 1998.58 CDMA: ACCESS AND SWITCHING CDMA ExchangeNodeRDPRDPRDPRDPRDPRDPSS /CDMA A. The satellite switched CDMA ... overview of switched CDMA networks, and presentedthe Satellite Switched CDMA (SS /CDMA) as a case study for such networks. TheSS /CDMA system illustrates how we can apply CDMA for both access...

Tài liệu CDMA truy cập và chuyển mạch P4 docx

... module.networks having CDMA access for two-way multimedia services called Cable Switched CDMA (CS /CDMA) (see Chapter 3, Section 3.1).Base Station Switched CDMA (BS /CDMA) In BS /CDMA we consider the ... The exchange node in a SW /CDMA using TMS.4.2 Switched CDMA (SW /CDMA) ArchitecturesIn this section we examine the network and switch architectures in SS /CDMA andSW /CDMA for terrestrial wireless ... called a Code Division Switch (CDS) may be appliedin switched CDMA networks such as SS /CDMA, BS /CDMA and CS /CDMA for rout-ing CDMA user-channels. We have analyzed the CDS performance and characterizedits...

Tài liệu CDMA truy cập và chuyển mạch P5 doc

... access isan orthogonal CDMA scheme (in both uplink and downlink) called Spectrally EﬃcientCode Division Multiple Access (SE -CDMA) (see Chapters 3 and 6). Each SE -CDMA CDMA: Access and Switching: ... through the switch even5The Satellite Switched CDMA Throughput5.1 OverviewAs we have discussed in Chapters 3 and 4, the satellite switched CDMA systemprovides on-board switching which operates ... Random TCAA (RTCA).5.5 ConclusionsIn this chapter, we have proposed a Satellite Switched CDMA (SS /CDMA) demandassignment system which provides multiple access and switching for both voice...

Tài liệu CDMA truy cập và chuyển mạch P6 doc

... we6The Spectrally Eﬃcient CDMA Performance6.1 OverviewAs we have discussed in Chapter 3, the SS /CDMA Traﬃc channels are based on aspectrally eﬃcient CDMA (SE -CDMA) . The SE -CDMA is designed to reuse ... is used over all of the beams.Code Cross-correlation for FO/SE -CDMA and MO/SE -CDMA Recall that for the FO/SE -CDMA (and MO/SE -CDMA) system Ts= LuTcandTc= LbTcc. Again let bkand ... performance of the FO/SE -CDMA, MO/SE -CDMA and SO/SE -CDMA systemsof Table 6.2 (Section 6.2) was evaluated in terms of the end-to-end BER. The basicTHE SPECTRALLY EFFICIENT CDMA 157transmission...

Tài liệu CDMA truy cập và chuyển mạch P7 ppt

... andSynchronization7.1 OverviewAs we have described in Chapters 3 and 6, the SS /CDMA uses orthogonal CDMA inboth uplink and downlink. The orthogonal CDMA can reject the interference betweenthe user traﬃc channels ... which synchronous CDMA (orthogonal orquasi-orhtogonal) attempted for use in the uplink or inbound channel. One suchexample is presented in reference [1], in which synchronous CDMA is proposed ... of the chip lengthfor orthogonal CDMA operation. This result has also been veriﬁed analytically inChapter 2. Such a requirement can be achieved easily if the CDMA system has arelatively narrow...

Tài liệu CDMA truy cập và chuyển mạch P8 pptx

... =1/7, N = 31.8Carrier Recovery for‘Sub-Coherent’ CDMA 8.1 OverviewIn this chapter we examine possible methods of carrier recovery for the SE- CDMA presented in Chapter 6. In particular, we propose, ... 1999.[12] M. Khairy and E. Geraniotis ‘BER of DS /CDMA Using Symbol-AidedCoherent Demodulation over Rician and Rayleigh Fading Channels’ IEEEISSSTA, 1998.188 CDMA: ACCESS AND SWITCHING(for the uncoded ... iteration, the probability of the bits is calculated according top(x(k)=1)=eL(k)/(1 + eL(k))200 CDMA: ACCESS AND SWITCHINGand the channel estimate is adapted after every iteration according toˆcl(m)=Ml=−M,l=0h(l)r1l(l...

Tài liệu CDMA truy cập và chuyển mạch P9 pptx

... Ampliﬁcation ofSynchronous CDMA 9.1 OverviewAs we have described in Chapter 3, the SS /CDMA uses orthogonal CDMA for bothuplink and downlink transmission. On board the satellite, each CDMA channel isrouted ... this study is the satellite switched CDMA systempresented in Chapter 3. The link access of the SS /CDMA is based on the SE- CDMA, which is a synchronous CDMA as described in Chapters 3 and 6. ... jRijkl=1NN−1n=0c(i)[n]c(j)[n]c(k)[n]c(l)[n],i= j = k = l234 CDMA: ACCESS AND SWITCHING9A.4 SER Evaluation for MPSK CDMA Let the outputs of the two branches of the ﬁrst correlator beZI=...

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