This article investigates a new model to improve the scalability of low-power long-range (LoRa) networks by allowing group multiple end devices (EDs) communicate with multi-antenna gateways simultaneously (i.e., in same time slot) on frequency band and using spreading factor. The maximum-likelihood (ML) decision rule is first derived for noncoherent detection information bits transmitted group....

Multiuser Transmission (MUT), the counterpart of Multiuser Detection(MUD) in the transmitter, can substantially enhance the performance of the CDMA downlink in frequencyselective channels. Besides linear Multiuser Transmission, known as Joint Transmission and Transmit Wiener filters, recently nonlinear MUT was proposed. The contribution of this paper is the extension of nonlinear Minimum BER Tr...

We consider noncoherent multiuser detection techniques for a system employing nonlinear modulation of non-orthogonal signals. Our aim is to investigate near-optimum noncoherent multiuser detection techniques that utilize the received signal structure while retaining reasonable complexity. Near-optimum approximations of the maximum likelihood detector are investigated where the signal structure ...

ABSTRACT We consider the problem of multiuser detection for CDMA (code division multiple access) systems where the codes of some users are known while others are unknown, group-blind multiuser detection. An example is at the base station of a cellular communication system with interference from both in-cell users, with known codes, and out-of-cell users, with unknown codes. In this paper we dev...

In this paper, we propose a new method of channel estimation for asynchronous additive white Gaussian noise channels in satellite communications. This method is based on signals correlation and multiuser interference cancellation which adopts a successive structure. Propagation delays and signals amplitudes are jointly estimated in order to be used for data detection at the receiver. As, a mult...

Adaptive Two-Stage Detection Scheme in Synchronous Two-User CDMA Systems by Yong Jiang A conventional single user detector is not optimum in the multiuser environment because the multiuser interference can not be modeled as an additive Gaussian process. Such a receiver is very vulnerable to the near-far situation. The receiver that is optimum for multiuser environment has high complexity and re...

In this paperwepresent a population declining ant colonyoptimization (PDACO) multiuser detector for asynchronous CDMA communications. Ant colony optimization (ACO) algorithms have already been used inmultiuser detection inCDMAsystems; however, as the pheromone accumulates, we may not get a global optimum because it stops searching early. PDACO can enlarge searching range through increasing the ...

| We focus on the design of multiuser receiver structures for Code Division Multiple Access (CDMA) communication systems, in the presence of multipath e ects and multiple sensors at the base station receiver. We present a exible and extensible framework that allows the use of an estimated e ective spreading code from the channel estimation phase, in the multiuser detection process. The effectiv...

In this paper, multi-cell channel estimation algorithm based on successive interference cancellation (SIC).This channel algorithm is also used for Time Division Synchronization Code Division Multiple Access Systems (TD-SCDMA). TD-SCDMA is the country's standard of 3G mobile telecommunication. This reduces the number of users in each timeslot, which reduces the implementation complexity of multi...

In this lecture, we present the mathematical analysis on the average bit error rate for multi-users in a single channel of the spread spectrum, Code Division Multiple Access (SS-CDMA) mobile radio system. We present expressions of BER performance of CDMA systems for a wide range of interference conditions for both synchronous case and asynchronous case, including Gaussian approximations (GA), I...