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Wireless network is based on packet switching concept and is capable of handling various types of applications. The challenge is to attain a better Quality of Service (QoS) for the like applications of real time and non-real time in an intriguing environment with varying bit rate, unexpected channel lay off. The intention of QoS provision is to afford the opted services for the users while utilizing...
In the past few years, the telecommunications field experienced a rapid evolution on two main grounds: Multiple mobile network interface terminals, and mobile radio technologies. The needs of the users in terms of flow and mobility are in constant increase, making it necessary to develop a new generation of networks. The latter would be a heterogeneous wireless environment in which different access...
Wireless technologies have been widely deployed in the last decade making users demand for continuous connectivity. Users not only demand being attached to a network, but possibly to the one with the highest performance, or at least to a network able to fulfill their requirements. To choose the best network among different candidates, the IEEE 802.21 standard has been developed. In this paper we aim...
WiMAX is a promising solution for last-mile broadband Internet access. 802.16m is a new IEEE standard featuring multi-carrier technology to meet the requirement of IMT-Advanced for next generation mobile WiMAX. The design goal of IEEE 802.16m is to achieve 1Gbps over-the-air data rate with the help of multi-carrier operation. However, multi-carrier operation brings many challenges. In this paper,...
The IMT-Advanced standardization process is executed by International Telecommunications Union Radiocommunication Sector (ITU-R) to define requirements to the next 4-th generation mobile communication systems and certify technologies meeting these requirements. This work presents results of the IEEE 802.16m and 3GPP LTE Release 10 technologies evaluation obtained by the Russian Evaluation Group (REG)...
In this paper, we present a review of automatic repeat request (ARQ) and hybrid ARQ (HARQ) mechanisms implemented or proposed in beyond 3rd generation (B3G) wireless systems based on OFDMA. In particular, we will focus on part of the IEEE 802.16 standard family (IEEE 802.16-2005, IEEE 802.16m) and on 3GPP Long Term Evolution (LTE). In the second part of this overview, some performance curves show...
The seamless integration of heterogeneous wireless access networks is currently one of the issues of major interest in the field of telecommunication systems. In an early future technologies like UMTS, WLAN and WiMAX will give broadband access to users that perform their voice/video calls or data sessions without knowledge of the specific technology their terminals are using, following the paradigm...
In current wireless standards like 3GPP LTE or IEEE 802.16 / WiMAX multiple access is based on orthogonal signalling using single-carrier frequency-division multiple access (SC-FDMA) or orthogonal frequency-division multiple access (OFDMA). Links between a base station and different terminals use mutually orthogonal radio resources. This paper studies potential gains in average cell throughput by...
Next-generation wireless networks such as LTE and WiMax can achieve throughputs of several Mbps with TCP. These higher throughputs, however, can easily be destroyed by frequent handoffs, which occur in urban environments due to shadowing. A primary reason for the throughput drop during handoffs is the out of order arrival of packets at the receiver. As a result, in this paper, we model the precise...
This paper describes the implementation of a flexible Turbo and LDPC outer modem engine which is capable of supporting the WiFi(802.11n), WiMax(802.16e) and 3GPPLTE standard on the same hardware resources. The chip is implemented in a 65 nm CMOS technology and occupies 10.37 mm2. The decoder flexibility is offered by means of an application-specific instruction-set processor (ASIP), with full datapath...
In this paper, a low-complexity symbol detector is presented targeting the emerging 3GPP LTE and WiMAX standards. The detector is the VLSI implementation of a novel MIMO detection algorithm recently proposed. Compared to the design in the reference, the detector performs better while consumes less silicon area. Including a microcode controlled channel preprocessing unit and a pipelined detection unit,...
This contribution provides insight into the performance of the currently deployed 3G cellular systems HSDPA and WiMAX. In extensive measurement campaigns we measured the physical layer throughput of these 3G systems in different environments (alpine and urban) and compare the results rigorously to their upper bounds derived from the well known Shannon capacity. By separating the observed losses into...
Fractional Frequency Reuse (FFR) is one of the key concepts for enhancing cell-edge performance of OFDMA networks. Standard FFR allows one sub-band to be allocated for each cell. This limits the performance improvement of cell edge users, especially those bandwidth-sensitive users. With flexible sub-band allocation, cell edge can be allocated more than one sub-band, thereby performance can be improved...
In this paper, we propose a framework to enhance user perceived quality in a multihomed terminal. Based on the observed media independent handover parameters from all the interfaces, the terminal is made aware of the performance of the different access networks and it can intelligently select the interface to send out the data packets. Several schemes, for the purpose of load balancing, are defined...
As one of the effective way to overcome the digital divide issue in the lightly populated area, the BWA (Broadband Wireless Access) system is expected and field trials have been conducted extensively in Japan. This paper introduces the results of BWA field experiments conducted in a typical intermediate and mountainous area in Japan. In the BWA network, WiMAX units are used as relay stations and R-LAN...
Mobile WiMAX is claimed to have the greatest potential of all wireless access technologies already in the markets with respect to network capacity, range, mobility, and quality of service support. Mobile WiMAX has also adopted MIMO as an essential element for increasing capacity and data propagation reliability. However, there are few publicly available studies demonstrating what is possible with...
This paper describes a solution for on-the-fly adapting the parameters of a video surveillance streams to system varying conditions, both in terms of data to be transmitted (number of streams to be sent) and of transmission conditions (quality of the available wireless link). This solution has been inserted in the system architecture of the EUREKA CELTIC BOSS project for enhancing the security of...
One of main challenges of fourth generation wireless networks (4G) will be the integration of various mobile technologies such as CDMA 1xEV-DO RA, UMTS/HSDPA and WiMAX. In this paper is investigated the interoperability between the CDMA 1xEV-DO RA and the UMTS/HSDPA in the 4G context. New algorithms for vertical handoff traffic acceptance are proposed considering the link occupation, the buffer occupation...
Modern wireless communication systems employ MIMO and feedback-two properties that make it especially difficult to measure the performance of such systems with reasonable effort in actual outdoor scenarios. In this paper, we will present a time, cost, and manpower efficient measurement approach to evaluate the throughput achieved by such systems. Summer/winter, large distance outdoor-toindoor/outdoor,...
Multi-hop relays will be deployed as one of the promising technologies for future cellular networks to enhance the performance of cell boundary users and to reduce deployment and operating cost. However, they have many challenges which include signaling overhead and latency in order to be practically deployed due to a hierarchical multi-hop structure, and the situation is much severer in uplink case...
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