This paper presents a broadband packet radio access scheme based on Orthogonal Frequency Division Multiplexing (OFDM) based access in the downlink and single-carrier based access with spreading including low-rate channel coding in the uplink for the systems beyond IMT-2000. In our design concept for radio access in both links, the spreading factor including the channel coding rate is optimally ...

Non-orthogonal multiple access (NOMA), in particular pattern division (PDMA), has been recently considered as the critical technologies deployed for 5G applications. However, optimizing power allocation (PA) at base station (BS) to increase sum throughput of downlink (DL) PDMA system still remains a challenge. Although this problem explored some extent by assuming that BS can obtain perfect cha...

Time reversal (TR) has been proposed as a competitive precoding strategy for low-complexity devices relying on ultra-wideband waveforms, it shifts the signal processing complexity to transmitter side. This transmit paradigm can address need low-power, receivers, which is particularly important Internet of Things. Due its spatio-temporal focusing property, TR also used design multiple access sch...

An alternative code-division multiple-access (CDMA) scheme to spread spectrum (SS), called spread time (ST) is proposed for badlimited multiple-access channels. ST-CDMA can be considered the be-frequency dual of SS-CDMA. In ST-GDMA pslendsraodan (PN) sequences are assigned to each user, and the Fourier tcrursf@rm of the transmitted pulse for a given user is d&mined by modulating the phase of th...

The use of spread spectrum signaling, motivated primarily by its antijamming capabilities in military applications, leads naturally to the use of Code Division Multiple Access (CDMA) techniques that permit the successful simultaneous transmission by a number of users over a wideband channel. In this paper we address some of the major issues that are associated with the design of multiple access...

Time-Division Multiple-Access (TDMA) and Code-Division Multiple-Access (CDMA) have received much attention as potentially attractive multiple-access techniques for wireless networks, such as the future Personal Communications Network. The standard TDMA cellular network is designed so that physically adjacent cells are assigned different frequency bands, or channels, in order to reduce inter-cel...

In CDMA (Code - Division Multiple - Access) systems multi - user accessing of a channel is possible. Under the assumptions of Optimum multi - user and decorrelating detector in CDMA systems. By using signals with zero and / or identical cross correlations, a simple and expandable decorrelating detector with optimum efficiency which can be easily implemented are proposed. Constructing these sign...

This paper deals with the performance of two different access techniques for the Two-Hop Decode-and-Forward (DF) Multiple-Access Relay Channel (MARC) which includes multiple source and relay nodes. In particular, cooperative Orthogonal Frequency Division Multiplexing (cOFDM) is compared with distributed Interleave Division Multiplexing Space-Time Codes (dIDM-STC). While cOFDM requires strict sy...