ALGORITHM OF MEASUREMENT-BASED ADMISSION CONTROL FOR GPRS

A trend in telecommunication has been to make steps towards centralized management of networks including power systems. The main motivation is operational cost saving. Technical specialists are only located in network management centers. The diagnostics and maintenance of power systems is done remotely using Internet protocol (IP) based access. Due to historical reasons, most of the sites do not have network access. The general packet radio service (GPRS) offers a simple and flexible solution to overcome this limitation. This paper describes the architecture of a GPRS based remote monitoring solution for power systems in GPRS networks. Furthermore, it presents and discusses results of a field trial carried out in a mobile service provider's GPRS network.

In this paper, a new sewage flow remote monitoring system over General Packet Radio Service (GPRS) is presented, which monitors the sewage flow parameter remotely in real time. In the proposed system, GPRS network is adopted as the wireless sensor network, and the data between the slave computer and the remote terminal are transmitted via the GPRS and Internet networks. Finally in the remote terminal, the Winsock control of Visual Basic 6.0 is responsible for displaying, storing and analyzing the data of the sewage flow. The system is easy to implement and has a high degree of automation, by which the acquisition, transmission and processing of the sewage flow data can be achieved in wireless, networked and intelligent manners.

This paper presents the design and analysis of general packet radio service (GPRS)-wireless local area network (WLAN) mobility gateway (GWMG) for the integration of GPRS and WLANs. The interworking between GPRS and WLANs is achieved by the GWMG that resides on the border of GPRS and WLAN systems. The design goal is to minimize the modifications in GPRS and WLANs as both systems are already widely available. By deploying the GWMG, users can seamlessly roam among the two systems. Unlike other related work, the proposed GWMG could be used when either the GPRS or WLAN is a user's home network. Both mathematical analysis and simulation are developed to analyze the performance. The proposed GWMG has also been implemented in a testbed comprising a commercial GPRS system. The results show that the GWMG could achieve a design goal that will effectively integrate GPRS and WLANs.

The General Packet Radio Service (GPRS) is being deployed by GSM network operators world-wide, and promises to offer users always-on data access at bandwidths comparable to that of conventional fixed-line telephone modems. Unfortunately, many users have found the reality to be rather different, experiencing very disappointing performance when, for example, browsing the web over GPRS.In this paper we investigate what causes the HTTP protocol and its underlying transport TCP to underperform in a GPRS environment. We examine why certain GPRS network characteristics interact badly with TCP to yield problems such as: link under-utilization for short-lived flows, excess queueing for long-lived flows, ACK compression, poor loss recovery, and gross unfairness between competing flows. We also show that many web browsers tend to be overly aggressive, and by opening too many simultaneous TCP connections can aggravate matters.We present the design and implementation of GPRSWeb - a mobile HTTP proxy system that mitigates many of the performance problems with a simple software update to a GPRS mobile device. The update is a 'client proxy' that sits in the mobile device, and communicates with a 'server proxy' located at the other end of the GPRS link close to the wired-wireless border. The dual proxy architecture collectively implements a number of key enhancements - an aggressive caching scheme that employs content-based hash keying to improve hit rates for dynamic content, a preemptive push of web page support resources to mobile clients, resource adaptation to suit client capabilities, delta encoded data transfers, DNS lookup migration, and a UDP-based reliable transport protocol that is specifically optimized for use over GPRS. We show that these enhancements result in significant improvement in overall WWW performance over GPRS.

Due to the growing interest in mobile data applications, the Global System for Mobile communications (GSM) has been extended by the General Packet Radio Service (GPRS). It allows the transmission of packet data at moderate bit rates using random access channels within the existing GSM infrastructure. This paper analyses the impact of using multiple channels in a GSM system for GPRS packet transmission. Different combinations of frequency reuse and channel coding are evaluated for 1, 4 and 8 packet data channels (PDCH) per cell. A tight frequency reuse of 1, together with a strong error coding scheme was found to provide the highest capacity. The increased trunking efficiency for a system with 8 PDCH yields a capacity gain of about 64% over a system with only 1 channel. The results indicate that mixing circuit and packet switched traffic causes inefficient use of system resources. Since GSM voice services usually require a frequency reuse of 3 or 7, a separate overlaying network for GPRS provides better resource utilization and maximizes the number of users fulfilling the specified quality of service (QoS) requirements.

General packet radio service (GPRS) is a packet oriented mobile data service on the 2G and 3G cellular communication systems global system for mobile communications (GSM). GPRS is the most widely used technology solutions to solve mobile communication combined with IP. Due to its advantage such as real-time online, binding billing, quick login, high-speed transmission, widespread coverage etc, it has been widely used in the remote monitoring and data transmission fields, etc. In this paper the PPP protocol of GPRS was researched in detail, moreover, the PPP protocol process based on GPRS was analyzed. In addition, it describes the composition and content, meaning and connection of the PPP protocol process and data exchange between terminal and monitoring center. Meanwhile, the TCP/ IP transmission protocol was discussed. it also gives three handshake data exchange situation which is connected by TCP/IP. It gives the specific application example of PPP and TCP/IP protocol exchanging data when connecting public wireless internet net with GPRS module. This article provides the essential basis for making further use of PPP and TCP/IP protocol to achieve the design of wireless transmission terminal.

The recent popularity of voice over IP (VoIP) services in the Internet world lies in the fact that in VoIP, voice packets are carried over the shared packet-switched network (the Internet) rather than on dedicated circuit-switched telephony network. This phenomenon reduces the cost of carrying the voice packets substantially. We propose that the concept of VoIP over wireless GPRS (General Packet Radio Service) also reduces the complexity of the GSM/GPRS architecture. Currently, the existing GSM (Global System for Mobile Communications) network carries the voice packets in the air link and converts it to circuit-switched PCM (Pulse Code Modulation) signal by using the voice transcoder. A 64 Kbps circuit-switched connection is then established through the existing PSTN (Public Switch Telephone Network). Wireless data packets on the other hand, share the same physical air link, but are carried through the GPRS packet-switched network. If we carry the voice on the same packet-switched network rather than on a separate circuit-switched network, then integration of data and voice would alleviate the necessity of circuit-switched components. However, maintaining the voice quality offers significant challenges. In this paper we propose a method of implementing the VoIP in GPRS network using H.323 protocol, and also identify the additional architecture requirements that will address some of the performance impediments of current GPRS VoIP implementation. The performance results for control message signals demonstrate the possibility of maintaining call set-up delay within the current delay standards. Analytical modeling of the voice traffic shows that significant improvements in terms of voice traffic capacity is possible with the help of a silent-detection scheme.

This paper presents a new wireless electricity acquisition system based on General Packet Radio Service (GPRS) technology which is designed according to the requirements of the seawave power for real-time and reliability of data transmission. The direct connection between GPRS network and Internet is effectively used in this system to establish the wireless communication channel, so as to realize the real-time and reliable collection and transmission of the power parameters of the seawave power system. The communication principles and characteristics of the GPRS technology are systematically introduced in this paper. The hardware and software composition, communication model and implementation of the wireless power acquisition system are described particularly. Extensive experiments show that the system has advantages of simple structure, high transfer rate, low running cost and high reliability.

General packet radio service (GPRS) is a part of the evolution path towards 3G. This paper investigates the effect of using two representative scenarios: a macro cellular system operating from a high altitude platform line of sight system and a terrestrial non-line-of-sight system, in each case a packet-based such as GPRS system is considered. The macro cellular layer will serve as second server to the mobile data terminals located in a microcellular layer, both layers form a Multi-layer cellular system. A comparison between GPRS system using only microcellular structure and when using both microcellular and macro cellular structures is evaluated. A simulator model was developed to study the behavior of data transmission between a GPRS server and data terminals via air interface. Simulation results show the validity of using macro cells to serve as a second layer, and how this can enhance the GPRS system performance.

A measurement-based admission control algorithm using a variable-size window is developed. The size of the measurement window is varied according to the estimate of the variance of the traffic in the measurement window. We use a small measurement window when the traffic is smooth (small variations) and we use large measurement window when the traffic is bursty (large variations). Our simulation studies provide results that complement two existing works (see Breslau, L. et al., 2000; Lee, S.K. and Song, J.S., 1998). On the one hand, we conclude that when the desired utilization rate is low, measurement-based admission control algorithms using a variable-size measurement window can improve the performance over algorithms using a fixed-size window. On the other hand, when the desired utilization rate is high, measurement-based admission control algorithms using a variable-size window and using a fixed-size window provide nearly identical performance results.

The purpose of call admission control in Integrated Services Networks is to offer a guarantee that Quality of Service (QoS) bounds are not violated due to the admission of new calls into the network. This is typically accomplished using the declared worst-case traffic descriptors for incoming calls, a solution which results in poor bandwidth utilization. A measurement-based admission scheme is an appealing alternative: not only does it offer adaptivity to changing traffic conditions, it also allows statistical multiplexing gains to be exploited. In this paper, we examine the problem of determining which traffic characterization a measurement-based admission control algorithm should require of sources requesting access. Building on the work of Jamin et al. (1995), we also propose an adaptive measurement-based admission control algorithm that simplifies the estimation process, and show that it can achieve a high level of utilization without violating its delay-based QoS guarantees.

In this article, the performance and capacity gain achievable with quality of service (QoS) management in packet switched radio networks based on the General Packet Radio Service (GPRS) are examined. Both the functions defined in the GPRS specification for QoS support and implementation-specific strategies for subscriber- and application-based Connection Admission Control (CAC) and scheduling are introduced. The feasibility of QoS provisioning in mobile core networks with use of DiffServ compared to present IP technology realizing a pure Best-effort service is examined in addition. To achieve this, simulation results of GPRS performance and system measures for different load situations are produced with the simulation tool GPRSim that models the realistic traffic behavior of a GPRS network.

In GPRS (general packet radio service) and UMTS (Universal Mobile Telecommunications System) networks, GGSN (gateway GPRS support node) serves as a default gateway while MSs (mobile stations) connect to outside networks such as the Internet. According to the GPRS/UMTS specifications, a fixed GGSN is assigned to serve an MS that attaches to the network and activates a session. The GGSN cannot be changed until the MS deactivates the session. Since packet-switched access is bursty in nature, GGSNs may suffer from unbalanced loads even if the numbers of serving MSs of GGSNs are equal. This paper presents a GGSN relocation method that can re-direct in-service MSs without breaking services and connections. The proposed approach enables a GGSN with a dynamic load balancing feature and improves the scalability of a GGSN system.

The data traffic is burstier and has longer connection time as compared to voice traffic. Global System for Mobile (GSM) was developed to carry the voice traffic and it is not suitable for carrying data traffic. General packet radio service (GPRS) has been well integrated in the GSM networks to accomplish efficient spectrum utilization for data traffic. In uplink, users are required to reserve the slot for sending packets using slotted ALOHA protocol. Depending upon coding scheme, each packet has some forward error correction capability and retransmissions are also done if errors are more. If a base transreceiver station (BTS) stops functioning (i.e., fails) then the users of its area will not get any service. In this case, absolute radio frequency channel number (ARFCN)s, which were assigned to the failed cell, should be transmitted by neighbor BTS such that some service should be available to users of the failed cell. It will affect the blocking probability, the cochannel interference thus bit error rate (BER), throughput etc. GPRS users will be adversely affected but it is far better than the case of no service. In this paper, the overall impact of BTS failure on the performance of GPRS uplink traffic has been quantified. The role of various parameters is discussed such that end users as well as cellular operator will get maximum benefits.

As a new medical method, the remote medical monitoring system is being paid more and more attention to. This article proposes a kind of remote medical monitoring system which is based on the sensor and GPRS (General Packet Radio Service, GPRS). The article first analyzes the necessity of the remote medical monitoring system, and then explains the advantages of the GPRS which is used in the remote medical monitoring system, and finally gives the architecture design of the remote medical monitoring system. The remote medical monitoring system is composed of two parts, which are mobile remote medical monitoring unit and the monitoring center. The user can carry the mobile unit along, while this mobile unit can real-timely monitor the physiological data from the user with sensors. When something abnormal happens, the intelligent control system automatically connects to the monitoring center. The monitoring center is composed of the monitoring station and the information management system. The information management system is connected with the monitoring center by a local area network, and its main function is to manage information such as the electronic map, the user's medical record and so on.