... and SpreadSpectrumSystems K Fazel Marconi Communications GmbH Germany and S Kaiser German Aerospace Center (DLR) Germany Multi-Carrier and SpreadSpectrumSystems Multi-Carrier and SpreadSpectrum ... 1.3 SpreadSpectrum Techniques 1.3.1 DirectSequence Code Division Multiple Access 1.3.2 Advantages and Drawbacks of DS-CDMA 1.3.3 Applications of SpreadSpectrum 1.4 Multi-Carrier SpreadSpectrum ... multi-carrier, spreadspectrum and multi-carrier spreadspectrumsystems We hope that this book will contribute to a better understanding of the principles of multi-carrier and spreadspectrum and...
... s p (t) is called a direct- sequence (DS) spreadspectrum signal The despreading operation is accomplished by multiplying s p (t) by a synchronous version of the spreading sequence: = x(t) · b(t), ... the sequence length, N The chip rate was 0.5 Mchip/s In the referred conditions, the aliasing begins at a sequence period length around 250 New PN Even Balanced Sequences For Spread- SpectrumSystems ... binary sequences for spreadspectrum multiplexing (Corresp.),” IEEE Trans Inform Theory, vol 13, no 4, pp 619–621, 1967 [18] R C Dixon, “Gold code sequence generators (see Appendix 7),” in Spread Spectrum...
... generates a random sequence of 1’s and −1’s The generated binary sequence is spread by a pseudorandom m -sequence by multiplying each information bit by this sequence in the DS spreading block Next, ... described model were run with the following parameters: the spreading factor/processing gain of the spreadspectrum system was g p = 127 and the spread signal was oversampled by The filter bank was an ... techniques in spreadspectrum communications,” Proceedings of the IEEE, vol 76, no 6, pp 657–671, 1988 [3] F Hsu and A Giordano, “Digital whitening techniques for improving spreadspectrum communications...
... wideband spreadspectrum cellular system,” July 1993 [44] TIA/EIA/IS-cdma2000, “Physical layer standard for cdma2000 spreadspectrum systems, ” Aug 1999 [45] Turin G.L., “Introduction to spread- spectrum ... Bs before spreading Signal bandwidth B after spreading Frequency Figure 1-9 Power spectral density after directsequence spreading There are many application fields for spreading the spectrum [13]: ... 1-4 1.3 SpreadSpectrum Techniques Spreadspectrumsystems have been developed since the mid-1950s The initial applications have been military antijamming tactical communications, guidance systems, ...
... PN spreadspectrum systems, ” IEEE, Transactions on Communications, vol 30, pp 913–924, May 1982 [31] Kondo S and Milstein L.B., “On the use of multicarrier directsequencespreadspectrum systems, ” ... before spreading the data symbols on each sub-channel with a userspecific spreading code in time direction, which corresponds to directsequence spreading on each sub-channel The same spreading ... Two-Dimensional Spreading Spreading in MC-CDMA systems can be carried out in frequency direction, time direction or two-dimensional in time and frequency direction An MC-CDMA system with spreading...
... With multi-carrier directsequencespread spectrum, each data symbol is spread over L multi-carrier symbols, each of duration Ts The complex-valued sequence obtained after spreading is given ... asynchronism Figure 2-24 shows the generation of a multi-carrier directsequencespreadspectrum (k) signal The data symbol rate is 1/Td A sequence of Nc complex-valued data symbols dn , n = 0, ... (L d0 − 1) 0 spreader c(0) spreader c(L − 1) serial-to-parallel converter (0) d0 L−1 user group (K d0 −L) spreader c(L − 1) spreader c(0) 1st data symbol per user + (K d0 − 1) L−1 spreader c(L...
... [15] Kaiser S., “Trade-off between channel coding and spreading in multi-carrier CDMA systems, ” in Proc IEEE International Symposium on SpreadSpectrum Techniques and Applications (ISSSTA’96), Mainz, ... International Symposium on SpreadSpectrum Techniques and Applications (ISSSTA’98), Sun City, South Africa, pp 115–120, Sept 1998 [18] Kaiser S and Fazel K., “A spread- spectrum multi-carrier multiple-access ... Workshop on Multi-Carrier Spread- Spectrum (MC-SS’97), Oberpfaffenhofen, Germany, pp 49–56, April 1997 References 113 [19] Kaiser S and Fazel K., “A flexible spreadspectrum multi-carrier multiple-access...
... Figure 4-17, CAZAC/M sequences are generated in the frequency domain and are embedded in I and R sequences The CAZAC/M sequences are differentially modulated The length of the M sequences is much ... sequences is much larger than the length of the CAZAC sequences The I and R sequences have the same length N1 , where in the I sequence (resp R sequence) the imaginary (resp real) components are ... frequency direction on OFDM symbols containing pilot symbols, followed by filtering in time direction on all sub-carriers is shown This ordering is chosen to enable filtering in frequency direction directly...
... band interference in PN spread- spectrum systems, ” IEEE, Transactions on Communications, vol 30, pp 913–924, May 1982 [44] Li Y., “Simplified channel estimation for OFDM systems with multiple transmit ... Effects of Phase Noise OFDM systems are more sensitive to phase noise than single-carrier systems due to the Nc times longer OFDM symbol duration and ICI [62][63] In OFDM systems, differential modulation ... information bits of each user k = 0, , K − 1, are spread by the corresponding spreading code, where Walsh–Hadamard codes are applied For the uplink, the spread data symbol of user k is mapped onto...
... to maintain orthogonality among the spread user signals by spreading in the time direction than in the frequency direction The concept of two-dimensional spreading is described in detail in Section ... For high coverage areas with high delay spread, large spreading factors can be applied and for low coverage areas with low delay spread, the smallest spreading factor can be used In HIPERLAN/2, ... support different multi-carrier or spread spectrum- based transmission schemes For instance, by choosing a spreading factor of one in both the time and frequency direction, one may obtain a pure...
... and Sawahashi M., “Variable spreading factor orthogonal frequency and code division multiplexing (VSF-OFCDM),” in Proc International Workshop on Multi-Carrier Spread- Spectrum & Related Topics (MC-SS ... how to exploit the frequency diversity are the technique of multi-carrier spreadspectrum and coding in the frequency direction — Spatial diversity: Spatially separated antennas provide replicas ... required symmetrical or asymmetrical transmission capacity, and whether they Multi-Carrier and SpreadSpectrumSystems K Fazel and S Kaiser 2003 John Wiley & Sons, Ltd ISBN: 0-470-84899-5 234 Additional...
... (STTC) 237–238 UMTS 253 Spatial diversity 233 Spreading codes 52–54 PAPR 54, 184–185 Spreading length 34, 49, 55, 201 Spreadspectrum 30–45 Spreadspectrum multi-carrier multiple access (SS-MC-MA) ... enlarging/spreading the spectrum Several spreading codes can be used for spectrum spreading Synchronous: users transmitting following a given time pattern Uplink (UL): direction from the TS to ... Small Office/Home Office Soft Output Viterbi Algorithm Serial-to-Parallel (converter) SpreadSpectrumSpreadSpectrum Multi-Carrier Multiple Access Solid State Power Amplifier Space–Time Coding...
... EXACT BER ANALYSIS AND DESIGN OF PRERAKE COMBINING SCHEMES FOR DIRECTSEQUENCE ULTRA-WIDEBAND MULTIPLE ACCESS SYSTEMS CAO WEI (B Eng, M Eng) A THESIS SUBMITTED FOR THE DEGREE OF DOCTOR ... 136 List of Publications 137 vii Summary Recently, directsequence ultra-wideband (DS UWB) communication systems have attracted much attention of both academia and industry because ... radio spectrum becomes very precious resource Though elaborate effort on well allocating spectrum resources has been continuously taken, it is necessary to find alternative approaches to exploit spectrum...
... động với FHSS Ví dụ DirectSequenceSpreadSpectrum Transmitter DirectSequenceSpreadSpectrum Transmitter DirectSequenceSpreadSpectrum Using BPSK Example Approximate Spectrum of DSSS Signal ... mã PN gồm k chíp mã tương ứng với từ tần số Trải phổ dãy trực tiếp DirectSequenceSpreadSpectrum DirectSequenceSpreadSpectrum (DSSS) Sử dụng mã trải phổ băng rộng để điều chế tín hiệu ... (Frequency Hopping SpreadSpectrum FHSS): Hệ thống trải phổ cách nhảy tần số sóng mang tập lớn tần số, mẫu nhảy tần giả ngẫu nhiên Trải phổ dãy trực tiếp (Direct SequenceSpreadSpectrum DSSS):...
... Reserved 18 DirectSequenceSpreadSpectrum q Spreadspectrum increases the bandwidth of the signal compared to narrow band by spreading the signal q There are two major types of spreadspectrum ... Narrowband vs SpreadSpectrum Narrowband (High Peak Power) Power SpreadSpectrum (Low Peak Power) Frequency February 2005 Copyright 2005 All Rights Reserved Narrow Band vs SpreadSpectrum q Narrow ... two spreadspectrum techniques to be used in the licensed free Industrial, Scientific, Medical (ISM) band, 2.4 GHz, thus 802.11 and 802.11b Frequency Hopping SpreadSpectrum (FHSS) and Direct Sequence...
... requiring spreadspectrum modulation: DSSS (Direct SequenceSpread Spectrum) and FHSS (Frequency Hopping Spread Spectrum) Only the RF transmission has significant presence in the market DSSS FHSS Spreading ... IQ-modulator Then they are spread with ‘ different’pilot sequences on the I and Q channels This pilot sequence or Short Code sequence has a length of 15 chips A ‘ PN-offset’in the pilot sequences is assigned ... hops/s or a channel dwell time of less than 400 ms DE NAYER (ir J Meel) IWT HOBU-fonds SpreadSpectrumSpectrum The spectrum of the transmitted signals determines the network packing DSSS FHSS 11 Msps...