An optical fast frequency modulation code division multiple access communication system is proposed. In this system, an electrically controlled tunable optical filter (TOF) is used to encode the modulated broadband light source. The code depends on the function set to the controller. Two-dimensional code named functional code is also proposed based on a shifted sine function. The function defin...

Abstract— Orthogonal frequency division multiplexing (OFDM) is an important technique to support high speed transmission of broadband traffic in wireless networks, especially broadband wireless local area networks (LANs). Based on OFDM, a new multiple access scheme, called OFDM-TDMA with subcarrier allocation (OFDMTDMA/SA), is introduced in this paper. It provides more flexibility in resource a...

Multiuser diversity can be used to significantly increase system throughput in wireless communication systems. The idea is to schedule users when they experience good channel conditions and let them wait when the channels are weak. In this thesis, several aspects on multiuser diversity OFDMA systems are investigated. An adaptive reduced feedback scheme for multiuser diversity OFDMA is proposed....

“In this paper, we introduce partial transmit sequence (PTS) based method to decrease the peak-to-average power ratio (PAPR) of the localized single-carrier frequency division multiple access (LFDMA) in the uplink systems. For a clip rate of 0.1% with user subcarriers of 64, system subcarriers of 256 with four different phase sequences; the gain of PAPR for the suggested PTS based LFDMA system ...

As the power consumption is an essential issue for designers of mobile devices The 3 Generation Partnership Project (3GPP) – Long Term Evolution (LTE) employs a multicarrier communication technique on the air interface, Single Carrier Frequency Division Multiple Access (SCFDMA), in uplink scenario and Orthogonal Frequency Division Multiple Access (OFDMA) in the downlink. SCFDMA core modulation ...

A survey and tutorial is provided on the subject of multiple-input–multiple-output (MIMO) multicarrier (MC) systems relying on the space–time shift keying (STSK) concept. We commence with a brief review of the family of MIMO systems, which is followed by the design of STSK systems in the context of MC modulation-based transmissions over dispersive wireless channels. Specifically, the STSK schem...

1 CDMA Concept 4 1.1 Basic Principles of Spread Spectrum . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.1.1 Direct Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.1.2 Frequency Hopping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.1.3 Time Hopper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.1.4 Hybrid Systems . ....

This paper compares different multiple access schemes for broadband wireless local loop systems with a total shared capacity of 156 Mb/s per radio cell. Time Division Multiple Access (TDMA) and Orthogonal Frequency Division Multiple Access (OFDMA) are appropriate system concepts. The focus is on adaptive equalization issues for both access schemes.