Modeling and simulation of mixed modulation formats for improved CDMA bandwidth efficiency

Raghavan, Srini; Holmes, J. K.

doi:10.1109/vetecf.2004.1404888

Cited by 3 publications

(5 citation statements)

References 2 publications

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“…sine BOC (SinBOC), cosine BOC (CosBOC) or alternate BOC (AltBOC) [3][4][5][6][7][8][9][10]. The BOC modulation splits the signal spectrum into two symmetrical components around the carrier frequency, by multiplying the pseudorandom (PRN) code with a rectangular sub-carrier [4].…”

Section: Background and Motivationmentioning

confidence: 99%

“…The signals selected for the main navigation systems nowadays, namely Navstar GPS (military-operated U.S. system) and the upcoming Galileo (civil-operated European system), are spread-spectrum signals, modulated either via binary/quaternary phase shift keying (BPSK/ QPSK) or by some variants of the so-called binary-offset-carrier (BOC) modulation, e.g. sine BOC (SinBOC), cosine BOC (CosBOC) or alternate BOC (AltBOC) [3][4][5][6][7][8][9][10]. The BOC modulation splits the signal spectrum into two symmetrical components around the carrier frequency, by multiplying the pseudorandom (PRN) code with a rectangular sub-carrier [4].…”

Section: Background and Motivationmentioning

confidence: 99%

“…Mean acquisition times for SinBOC modulation with odd N BOC order: N BOC ¼ 3 (e.g. SinBOC (15,10)), serial search, single frequency bin, 4092-chip code length, P fa ¼ 10 À3 , N c ¼ 30 ms, N nc ¼ 6. Left plot: dual-SB processing; right plot: single-SB processing.…”

Section: Performance Comparisonmentioning

confidence: 99%

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Low‐complexity unambiguous acquisition methods for BOC‐modulated CDMA signals

Lohan

Burian

Renfors

2008

Satell Commun Network

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SUMMARYThe new M-code signals of GPS and the signals proposed for the future Galileo systems are of splitspectrum type, where the pseudorandom (PRN) code is multiplied with rectangular sub-carriers in one or several stages. Sine and cosine binary-offset-carrier (BOC) modulations are examples of modulations, which split the signal spectrum and create ambiguities in the envelope of the autocorrelation function (ACF) of the modulated signals. Thus, the acquisition of split-spectrum signals, based on the ambiguous ACF, poses some challenges, which might be overcome at the expense of higher complexity (e.g. by decreasing the step in searching the timing hypotheses). Recently, two techniques that deal with the ambiguities of the ACF have been proposed, and they were referred to as 'sideband (SB) techniques' (by Betz, Fishman et al.) or 'BPSK-like' techniques (by Martin, Heiries et al.), since they use SB correlation channels and the obtained ACF looks similar to the ACF of a BPSK-modulated PRN code. These techniques allow the use of a higher search step compared with the ambiguous ACF situation. However, both these techniques use SB-selection filters and modified reference PRN codes at the receivers, which affect the implementational complexity. Moreover, the 'BPSK-like' techniques have been so far studied for even BOC-modulation orders (i.e. integer ratio between the sub-carrier frequency and the chip rate) and they fail to work for odd BOC-modulation orders (or equivalently for split-spectrum signals with significant zero-frequency content). We propose here three reduced-complexity methods that remove the ambiguities of the ACF of the split-spectrum signals and work for both even and odd BOC-modulation orders. Two of the proposed methods are extensions of the previously mentioned techniques, and the third one is introduced by the authors and called the unsuppressed adjacent lobes (UAL) technique. We argue via theoretical analysis the choice of the parameters of the proposed methods and we compare the alternative methods in terms of complexity and performance.

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Section: Background and Motivationmentioning

confidence: 99%

Section: Background and Motivationmentioning

confidence: 99%

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Low‐complexity unambiguous acquisition methods for BOC‐modulated CDMA signals

Lohan

Burian

Renfors

2008

Satell Commun Network

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“…For example, if N pieces = 2 and FBB efw approach is used for Sin-BOC(1,1) case, the powers per piece of the positive-sideband lobe are 0.10 and 0.34, respectively (hence, P maxpp = 0.34). Again, these powers can be derived straightforwardly, via the formulas shown in [1,3,4,20].…”

Section: Test Statistic Distributionmentioning

confidence: 99%

Analysis of Filter-Bank-Based Methods for Fast Serial Acquisition of BOC-Modulated Signals

Lohan

2007

J Wireless Com Network

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Binary-offset-carrier (BOC) signals, selected for Galileo and modernized GPS systems, pose significant challenges for the code acquisition, due to the ambiguities (deep fades) which are present in the envelope of the correlation function (CF). This is different from the BPSK-modulated CDMA signals, where the main correlation lobe spans over 2-chip interval, without any ambiguities or deep fades. To deal with the ambiguities due to BOC modulation, one solution is to use lower steps of scanning the code phases (i.e., lower than the traditional step of 0.5 chips used for BPSK-modulated CDMA signals). Lowering the time-bin steps entails an increase in the number of timing hypotheses, and, thus, in the acquisition times. An alternative solution is to transform the ambiguous CF into an "unambiguous" CF, via adequate filtering of the signal. A generalized class of frequency-based unambiguous acquisition methods is proposed here, namely the filter-bank-based (FBB) approaches. The detailed theoretical analysis of FBB methods is given for serial-search single-dwell acquisition in single path static channels and a comparison is made with other ambiguous and unambiguous BOC acquisition methods existing in the literature.

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“…In some earlier papers capacity improvement achievable by mixing the BOC or S-BOC with the NRZ format has been discussed [1]. In this paper we consider mixing three formats such as NRZ, BOC, and SBOC, and the expected improvements are considered.…”

Section: Introductionmentioning

confidence: 99%

Multi-format signaling for improved throughput rate transmission

Raghavan¹,

Holmes²

2005

2005 IEEE Aerospace Conference

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BIOGRAPHY Dr. Srini Raghavan has over 25 years of experience in design, simulation, and analysis of satellite communication systems, spread spectrum systems, and signal processing. Currently he is supporting several communication systems and GPS-related activities at The Aerospace Corporation as a Senior Engineering Specialist. He has a B.S., and an M. Tech. in Engineering from India, and M.S. and Ph.D. degrees in electrical engineering from the University of Missouri, Rolla. He is a senior member of IEEE, member of ION, Eta Kappa Nu, and Sigma Xi. Dr. Jack K. Holmes is presently at The Aerospace Corporation in the Communication Systems Subdivision and holds the title of Distinguished Engineer. He has over 43 years experience in analysis, simulation, and design of communication systems. He has been heavily involved in the GPS M-code modernization effort. He is author of the 1982 book entitled "Coherent Spread Spectrum Systems" and approximately 45 papers in the area of communications, synchronization, and GPS-related subjects. He is a senior member of IEEE, a member of ION, and is a member of Tau Beta Pi and Sigma Xi. He received his B.S., M.S., and Ph.D. degrees from UCLA in electrical engineering.

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Modeling and simulation of mixed modulation formats for improved CDMA bandwidth efficiency

Cited by 3 publications

References 2 publications

Low‐complexity unambiguous acquisition methods for BOC‐modulated CDMA signals

Low‐complexity unambiguous acquisition methods for BOC‐modulated CDMA signals

Analysis of Filter-Bank-Based Methods for Fast Serial Acquisition of BOC-Modulated Signals

Multi-format signaling for improved throughput rate transmission

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