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In this paper, we propose the Nash bargaining solution for the interference problem in cellular networks. The base-stations of neighboring cells negotiate with each other to determine the best number of channels that should be allocated to their edge users. While cells optimize the allocated resources on a local level, the bargaining process acts as a common framework that combines the optimization...
Resource reservation is one of the effective solutions in guaranteeing the quality-of-service (QoS) in communication networks. In this paper, we propose a novel resource reservation scheme for dynamically managing the bandwidth resources in IEEE 802.11e-based wireless local area networks (WLANs). The proposed solution consists of two components namely (i) dynamic medium access control (MAC) scheduler...
The faster-than-Nyquist (FTN) signaling has been of interest in the research literature due to recent advances in pre-coding and equalization techniques allowing practical removal of the intersymbol interference (ISI). Since the structure of ISI is deterministic in the FTN signaling, a data pre-coding at the transmitter to combat ISI is of practical importance. It is shown, however, that such pre-coding...
When passed through a high power amplifier (HPA), downlink direct sequence-code division multiple access (DS- CDMA) signals result in additional out-of-band emissions, or spectral regrowth, which could affect adjacent channels. In this paper, we explore which characteristics of the input CDMA signal, in relation to the amplifier characteristics, contribute to spectral regrowth. These characteristics...
We propose a primary path switching scheme to provide a seamless handover for dual-homed mobile terminals. This scheme is suggested as an enhancement to the mSCTP protocol. With our scheme, a mobile terminal performs primary path switching before it becomes unavailable due to its primary path drop. The improvement of the scheme comes from considering the temporal velocity of the mobile terminal with...
This paper presents a joint study of several intercell interference coordination strategies considering both static and dynamic approaches, and with different adjustments in their basic parameters. A wide evaluation is presented with special emphasis on the efficiency vs. fairness tradeoff. Besides, additional performance metrics have been considered as enablers of a full understanding of the strengths...
Carrier aggregation (CA) has been proposed to aggregate two or more component carriers (CCs) to support a much wider transmission bandwidth for LTE-Advanced systems. With carrier aggregation, it is possible to schedule a user equipment (UE) on multiple component carriers simultaneously. In this paper, we evaluate the performance of uplink CA in LTE-Advanced systems with different CC allocation schemes...
60 GHz technology has been proposed recently for multi-Giga-bit/s access within different application scenarios, e.g. in crowded multi-user public transportation (PT) environments. Hence, channel sounders that are used to investigate multipath propagation and multi-user access techniques including spatial diversity and beam-forming in time-variant shadowing environments require ultra-wideband (UWB)...
The latest generation of wireless networks use OFDMA (Orthogonal Frequency Division Multiple Access) transmission technology in the downlink (e.g, WiMAX and LTE). The downlink is divided into bandwidth units and UEs (User Equipments) are each allocated a subset of these. Since at most one UE is assigned to each of these units, downlink transmissions within a sector are orthogonal. However, the transmission...
Re-farming of 900 MHz band into HSPA has been started and is likely to happen later with LTE. Typically operators have less than 10 MHz block of 900 MHz spectrum and therefore co-existence of two systems in that band is causing challenges. One of the major issues is the high GSM voice traffic that will remain in the GSM network. How to cope the same traffic with significantly less bandwidth for GSM?...
WANETs is a recent network architecture where the nodes are spread all over the world but behave exactly as if they are part of a single-hop or multi-hop wireless networks at the PHY and MAC layers. Without distinguishing data packets and noise, the Software Defined Access Point (SoDA) samples the wireless channel for the uplink and multicasts the sampled data via Internet to other SoDAs. This leads...
The aim of this article is to introduce an approach to providing connectivity on public transport connecting to the wider Internet via heterogeneous networks and prioritizing traffic according to service classes. We present a packet prioritization for each service class: premium, intermediate and default. A railway scenario is considered as our case study to evaluate the prioritization mechanisms...
This paper describes the implementation detail of an ultra wideband transmitted reference pulse cluster (TRPC) system. The newly proposed TRPC signaling structure consists of multiple pulses with uniform and compact spacing. It overcomes the major hurdle to practical implementation of conventional transmitted reference (TR) systems, that is, the long wideband delay line requirement. In addition, TRPC...
Ultra-wideband (UWB) techniques are recently targeted as a broadband short range solution for in-flight-entertainment (IFE) systems. Despite the in-cabin channel can be considered as an indoor channel, under the current aviation regulations, and due to the usual metal cabins and cylindrical shapes, these scenarios are particular for wireless applications. In this paper is presented an experimental...
Thanks to silence suppression, the VoIP capacity can be improved. When the voice users are listening or thinking, the VoIP system does not need to allocate resources to them, thereby being able to accommodate more users. The main issue is how to immediately allocate resources to the user, when the user transits from the silence state to the talkspurt state. The IEEE 802.16e/m system provides two typical...
We capture both the economical and technical aspects of the dynamic spectrum sharing to improve the underutilization of the scarce but valuable radio spectrum and the service providers' revenue. Especially, we investigate the optimal mapping between the service requester pool (SRP) and the service provider pool (SPP) in the coexistence context of multiple heterogenous cognitive radios. Both the optimal...
Wireless equipped machines are increasing greatly in recent years, among which the cellular network based machine-to-machine communication (M2M) has shown the advantages of better coverage and lower network deployment cost. However, the current cellular network is designed for human-to-human communication, targeting the voice/media transmission with low access delay and high throughput, so the machines...
In this paper, we propose a subcarrier suppressed transmission scheme that improves the frequency utilization efficiency of STICS (Satellite/Terrestrial Integrated Mobile Communication System), which shares the same frequency band between satellite and land mobile systems. Applying our proposal to the OFDM-based land system overcomes the resource assignment limits of the frequency sharing scheme and...
To overcome the problem that the transmission rate of a multicast channel is limited by the user with the worst channel quality, which causes the total system throughput to be low, the use of both multicast and unicast channels for multicast service is considered in this paper. Unicast channels, in addition to a multicast channel, are allocated to users with signal-to-noise ratios (SNRs) lower than...
The pressure of the energy bill from operators and the request of the environmental protection from the governments and publics results in more urgent requirement on the energy consumption and CO2 emission. Traditionally, adaptive modulation has been proven to be an efficient solution to improve the system performance over the radio fading channels. To obtain the design insights for energy efficient...
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