Code time division multiple access: an indoor cellular system

Ruprecht, J.; Neeser, Fredy; Hufschmid, M.

doi:10.1109/vetec.1992.245470

Cited by 31 publications

(3 citation statements)

References 4 publications

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“…Given , the prefix of is its cyclic extension defined by . Assuming , the prefix technique transforms a sliding convolution into a circular one as (2) or simply with the understanding that (2) is defined only in [0, ]. This relationship is the basis for OFDM [4] as well as for the new system introduced below.…”

Section: Letmentioning

confidence: 99%

A combined OFDM-CsDMA approach to cellular mobile communications

Ping

1999

IEEE Trans. Commun.

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We present a combined orthogonal frequencydivision multiplexing (OFDM) and code-division multiple-access cellular system. It is derived from the OFDM model by introducing an extra code-shift division multiple access layer. This mitigates intercell interference without affecting intracell orthogonality and such property can be maintained in multipath environments. The new scheme is suitable for both up and down links. It retains the low-receiver complexity property of the OFDM system.

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Section: Letmentioning

confidence: 99%

A combined OFDM-CsDMA approach to cellular mobile communications

Ping

1999

IEEE Trans. Commun.

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“…Inverse filters have been used in radar pulse-compression systems to reduce range sidelobes. Recently, because of the emerging interest in the multiple-access communication research, they have been suggested as an efficient way of reducing multiple-user interference in common-code multiple-access (CCMA) networks [1]. An inverse filter is a device which accepts a spreading-sequence modulated pulse train and demodulates it back into a single pulse.…”

Section: Introductionmentioning

confidence: 99%

Sequence design for IIR inverse filter pulse compression

Wang

Scholtz

1995

IEEE Trans. Aerosp. Electron. Syst.

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An infinite impulse response (IIR) inverse filter structure is presented, and compared with the performance of two finite impulse response (FIR) designs. The IIR design is shown to provide better performance and be able to improve further (e.g., -1.4 dB in sidelobe levels per unit delay increase for the length-13Barker sequence) by increasing delay. The performance parameters of this IIR inverse filter suggest a design criterion for sequences on which the filter operates, that is related to the roots of the Z transform polynomial of the sequence. The sidelobe-optimal sequence derived according to this criterion is shown to provide sharper sidelobe reduction (-6 dB per unit delay increase for the sidelobe-optimal length-13 sequence).

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“…As examples, we will consider three broadband access techniques that separate the users in different ways prior to scrambling, spreading in frequency or spreading in time., respectively: In Code Frequency Multiple Access (CFDMA) [4], the users are separated by frequency division. In Code Time Division Multiple Access ( C T D M A ) [3], the users are separated by time division. In Code Code Division Multiple Access (CCDMA) as proposed by Qualcomm [2], the users are separated by code division (CDMA).…”

Section: Introductionmentioning

confidence: 99%

Importance sampling technique for multi-user CDMA-like systems in discrete-time multipath fading environments

Jung¹,

Ruprecht²

Proceedings of GLOBECOM '93. IEEE Global Telecommunications Conference

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Monte-Carlo simulations of multi-user systems using code division multiple access (CDMA) are by nature rather inefficient because of the high sampling rates implied in the processing of the spread signal. One promising way to improve simulation efficiency is to make use of improved importance sampling (11s) [l]. This technique is based on a translation of the original probability density of the noise process in order to generate more errors and weighting these errors afterwards. This yields a BER estimate with the same variance for a reduced number of simulation runs. In this paper, the application of 11s is made to CDMA-like multi-user systems over multipath fading channels. In contrast to classical CDhdA, these broadband systems achieve a certain degree of orthogonality between the users thus allowing an enhanced spectral efficiency.

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Code time division multiple access: an indoor cellular system

Cited by 31 publications

References 4 publications

A combined OFDM-CsDMA approach to cellular mobile communications

A combined OFDM-CsDMA approach to cellular mobile communications

Sequence design for IIR inverse filter pulse compression

Importance sampling technique for multi-user CDMA-like systems in discrete-time multipath fading environments

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