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Receiving sensitivity of communication system is required to improve as the recent growth of data service in mobile communication. Thus, the interference caused by passive intermodulation (PIM) attracted more attention in the research of mobile communication. On the other hand, point of interface (POI) plays a more and more important role in practical application at recent years, in order to solve...
In satellite networks, the design of MAC schemes which achieve high performance is an important and widely studied problem. Random access is recognized as an appealing solution for these scenarios. In the literature so far, two main research lines have been followed: diversity slotted Aloha-like protocols and spread spectrum Aloha schemes. The goal of this work is to analyze the performance of these...
In this treatise, the performance of Code division multiple access (CDMA) system is investigated using multi-user transmitter pre-processing (MUTP). The MUTP is promising signal processing technique which is carried out at the transmitter side to reduce the burden of detector and hence low complexity receiver is made feasible at mobile station (MS) in the context of downlink (DL) communication. Further,...
In the world of telecommunication, demand for 3G mobile communication services still dominates the global market. It continues to grow despite the introduction of new technologies such as LTE and LTE-A. Hybrid Automatic Repeat Request (HARQ) and Adaptive modulation and coding (AMC) are among the key performance enhancing techniques adopted in High Speed downlink packet access (HSDPA). Limiting the...
Transmission of information in nano-networks can be implemented by the emission and reception of molecules in diffusion-based molecular communications. Since the propagation environment is shared among multiple nodes, the molecules emitted by different transmitters cause interuser interference (IUI). In this paper, we propose molecular code division multiple access (MCDMA) to overcome the IUI caused...
A novel code division multiple access (CDMA) using cyclic shift keying (CSK) signaling, namely CSK-CDMA, has been proposed for multiuser underwater acoustic communication. The proposed method uses the cyclic correlation characteristic of spread spectrum signals and time reversal processing to increase the data rate each user and to reduce the complexity of the receiver. In CSK-CDMA system, multiple...
A detailed software-defined receiver (SDR) architecture for navigation using cellular code division multiple access (CDMA) signals is presented. The cellular forward-link signal structure is described and models for the transmitted and received signals are developed. Particular attention is paid to relevant information that could be extracted and subsequently exploited for navigation and timing purposes...
In this paper, we introduce a model for Multiple-Input Multiple-Output (MIMO) Space Division Multiple Access (SDMA) into the analysis of a multi-hop millimeter wave network under the classic Network Utility Maximization (NUM) framework with Maximum Back Pressure scheduling (MBP). We show that the proof of convergence of MBP remains valid when we allow the scheduler to select multiple links to the...
The demand for the wireless communication is growing rapidly from last few years. Demand arises a lot of advancement in the communication. In this paper introduction of IDMA, complete analysis and comparison of IDMA with CDMA and OFDM is done for the single access channel. IDMA introduce the interleaving technique as means of user separation instead of digital signatures in CDMA and subcarriers in...
In this paper, we study the design of low density signature-orthogonal frequency division multiple access (LDS-OFDM). Compare to the conventional OFDMA system, LDS system has some desirable properties that allows system operating at overloaded conditions. LDS-OFDM system has been shown that outperforms the corresponding OFDMA system. In this paper, we focus on the design of the LDS degrees distribution,...
This paper investigates a correlator-type receiver based on oversampling technique, which can exploit flat-fading characteristic to enhance the performance of chaotic directsequence/ code division multiple access (Chaotic DS/CDMA) systems over multipath fading channels. At the input of the receiver, the incoming signal is oversampled before putting into the correlator. This oversampling process aims...
As a natural limited resources, the radio frequency spectrum should be managed and used as efficiently as possible. The Government as regulator has a responsibility to manage and regulate the spectrum to prevent interference. One example of the many problems in Indonesia that must be solved is the spectrum in 2.1 MHz frequency band for 3G services. The CDMA 2000 and UMTS system occupy adjacent band...
Traditional algorithms for Media Access Control (MAC) in Mobile Ad Hoc Networks (MANET) such as CSMA-CA allow only a single user to transmit at a given time. This means that the sum throughput in a MANET cannot increase to service additional users. Such MAC protocols disregard the possibility that by utilizing multiple antenna processing to handle interference intelligently at the Physical layer (PHY),...
Nowadays, receivers can separate multiple transmitted packets simultaneously through the use of advanced signal processing techniques. This capability is called multi-packet reception (MPR). Currently, several proposals have been made to modify the operation of 802.11 and take advantage of the MPR capability. However, under multi-rate transmissions, these techniques suffer from the phenomenon known...
In this paper, we propose a distributed scheduling scheme for internet-of-things (IoT) wireless devices. The scheduling determination that maximizes overall sum rate of the network is formulated as an optimization problem, which is very challenging because there exists no centralized coordinator in the typical IoT network. To resolve this, we introduce the-state-of-the-art message-passing framework...
Military communications face increasingly congested environments requiring spectrally efficient approaches capable of contending with many users and interference. We evaluate the over-the-air performance of recently designed minimum total squared correlation (MinTSC) signature sets compared to maximal length pseudorandom binary spreading sequences (m/PN) under a variety of interference conditions...
In modern communication era wireless communication devices play very important role. The demand of wireless devices are increasing day by day, as they are becoming omnipresent in communication system. These wireless devices are energy limited because it needs high amount of information. This constraint degrades the two design parameters i.e. power efficiency and production cost of the system. We can...
In this work we consider an OFDM-SDMA downlink with a real life, nonlinear Power Amplifier (PA). It is well known that a nonlinear PA produces nonlinear distortions. We propose a novel iterative algorithm based on Zero Forcing (ZF) precoding to cancel the nonlinear distortions seen at the mobile devices while preserving the interference-free reception due to ZF. The proposed algorithm also keeps the...
We study the application of analog Joint Source Channel Coding (JSCC) techniques for the transmission of discrete-time, continuous-amplitude source information symbols over the Multiple-Input Multiple-Output (MIMO) Broadcast Channel (BC). Two channel access methods are proposed with different requirements regarding channel knowledge at transmission: Code Division Multiple Access (CDMA) and linear...
We consider overloaded (non-orthogonal) code division multiple access multiuser wireless communication systems with many transmitting users and one central aggregation node, a typical scenario in e.g. machine-to-machine communications. The task of the central node is to detect the set of active devices and separate their data streams, whose number at any time instance is relatively small compared...
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