Multi-rate communication systems are considered for the transmission of Direct-Sequence Code-Division Multiple-Access wireless signals. Performance for jointly optimal detection is studied in the context of multi-code access where high data rate users multiplex their information streams onto multiple codes; and variable spreading length access where signature sequences of diierent lengths are a...

This letter considers multiuser detection in variable-spreading-length multi-rate direct-sequence code-division multiple-access systems. A two-layer spreading (TLS) code scheme is proposed which facilitates the low-complexity adaptive implementation of linear minimum mean-square error multiuser receivers in a dual-rate system. It is demonstrated via large system analysis and simulation that imp...

A new methodology for the design of high-capacity anti-collusion hiding codes in a large-scale fingerprint-based traitor tracing system is proposed in this work. We consider a hiding code of MN bits, where M bits are used as the user ID and N bits are the length of the spreading codes. Since each user is assigned one out of 2 ID numbers and one out of N spreading codewords, the total number of ...

IDMA is being thought as a strong candidate for radio access in cellular mobile communication systems. It is attractive for wireless access because of its numerous advantages over TDMA, FDMA and CDMA. The InterleaveDivision Multiple-Access (IDMA) scheme is known for property of orthogonality amongst its user-specific interleavers. The interleavers are, therefore, referred has the heart of IDMA ...

Introduction: Improving the capabilities of multimedia communications is the target for third generation mobile communications systems. A variety of data services from low to very high bit rates is required; most services offered by current mobile radio systems are limited to voice and voice-band data services. Recently, direct sequence code division multiple access @S-CDMA) [l] has been drawin...

The wideband code-division multiple access (CDMA) concept (FMA2) developed in the European FRAMES project supports variable data rate transmission. The data rate can be altered by changing either the spreading factor or by using multiple spreading codes in parallel. In order to facilitate exible changing of data rate, variable length orthogonal Walsh codes are used for channel separation, follo...

SUMMARY In this paper, a new large spreading code set with a uniform low cross-correlation is proposed. The proposed code set is capable of (1) increasing the number of assigned user (capacity) in a multicarrier code division multiple access (MC-CDMA) system and (2) reducing the peak-to-average power ratio (PAPR) of an orthogonal frequency division multiplexing (OFDM) system. In this paper, we ...

| Future wireless systems will need to accommodate information sources with diierent data rates. Direct-Sequence Code-Division Multiple-Access (DS/CDMA) is a multiple access technique that is well suited to provide multi-rate access. Thus, in this paper, multi-rate communication systems are considered for the transmission of DS/CDMA wireless signals. Performance for maximum likelihood-based det...

The creation of the new L1C GPS signal presented the opportunity to choose both a family of spreading codes and an associated family of overlay codes. This paper describes the rationale and construction of these families. The families were created from extensive searches with each search requiring its own fine-tuned techniques and search criteria. The L1C spreading codes comprise 210 pilot/data...