Channel allocation for GPRS

Based on the GSM radio architecture, the general packet radio service (GPRS) provides users data connections with variable data rates and high bandwidth efficiency. In the GPRS service, allocation of physical channels is flexible, i.e., multiple channels can be allocated to a user. We propose four algorithms for the GPRS radio resource allocation: fixed resource allocation (FRA), dynamic resource allocation (DRA), fixed resource allocation with queue capability (FRAQ), and dynamic resource allocation with queue capability (DRAQ). We develop analytic and simulation models to evaluate the performance for these resource allocation algorithms in terms of the acceptance rate of both GPRS packet data and GSM voice calls. Our study indicates that DRAQ (queuing for both new and handoff calls) outperforms other algorithms     

Performance analysis of channel de-allocation schemes for dynamic resource allocation in GSM/GPRS networks

Channel de-allocation for GSM voice call (DASV) has been considered for dynamic resource allocation in GSM/GPRS networks. Two new de-allocation schemes are proposed: de-allocation for GPRS packet (DASP) and de-allocation for both GSM voice call and GPRS packet (DASVP). An analytic model with general GPRS data channel requirement is derived to evaluate the performance of the schemes in terms of GSM voice call incompletion probability, GPRS packet dropping probability, average GPRS packet transmission time and channel utilisation.     

TCP/IP在GPRS/EGPRS网络中的应用及影响

通用分组无线业务/增强型数据速率演进技术（GPRS/EGPRS）服务扩展了当前世界上最流行的第二代移动系统——基于语音的GSM,使其能够收发基于分组的数据。随着移动通信技术的发展和业务的多样化,人们对数据业务的需求不断增加,GPRS/EGPRS网络优化也成为了重中之重。除传统的无线网络及核心网络优化外,将其以端到端的思路分析,看为无线＋IP网络技术,成为了新的优化思路。因此传输控制协议/因特网互联协议（TCP/IP）作为互联网固有的最为广泛的传输协议在无线分组数据业务网络中同样得到广泛应用。主要就TCP/IP协议在GPRS/EGPRS中的应用其影响进行了分析。     

Concepts, services, and protocols of the new GSM phase 2+ generalpacket radio service

For almost three years the European Telecommunications Standards Institute (ETSI) has been working on the specification of the general packet radio service (GPRS) for the Global System for Mobile Communications (GSM). In the course of 1997 standardization will come to an end, and a first introduction of GPRS by a service provider or network operator is likely to take place in 1999. The new service will accommodate data connections with variable bit rates and high bandwidth efficiency, and thus offers the possibility to attract a wide range of new applications to GSM networks. In this article possible applications and elementary concepts and service characteristics of GPRS are explained in detail. Furthermore, a medium access control protocol that conforms to the draft standard proposal for the GPRS air interface is introduced and analyzed. Thereafter, the simulation model is described and simulation results presented. The performance analysis carried out shows reasonable performance even under high load conditions     

"通信原理"课程的系统级实验建设

本文分析了“通信原理”课程教学实验的现状,结合最新科研成果设计并实现了“通信原理”系统级实验,包括数字基带仿真、服务发现、局域网接入、电话网接入、语音传输、数据传输、图像传输、无线多点组网、通信系统性能评价和GSM／GPRS接入。     

Supporting IP QoS in the General Packet Radio Service

The General Packet Radio Service is the current enhancement in the GSM infrastructure, capable of handling Internet protocol traffic for mobile computing and communications. A major deficiency of the current GPRS specification is the lack of adequate IP quality of service support. Two schemes for enhancing the GPRS architecture with the existing IP QoS support architectures, IntServ and DiffServ, are proposed. Solutions are proposed to the problem of establishing QoS reservations across the GPRS core network, and the required signaling enhancements and modifications in the components of the GPRS architecture are identified. Of the two proposed schemes the IntServ one requires frequent refreshing of state information and extra signaling. To quantify the effect that signaling overhead has on GPRS operation and performance, a simulation model of the proposed IntServ architecture was developed, which includes models of the GPRS cellular infrastructure, network traffic, and user movement. The obtained simulation results show that the proposed IntServ architecture demonstrated good scalability, even for large user populations     

无线分组域时分信道资源计算方法

GPRS技术曾经希望使用话音业务剩余的无线资源提供分组数据的传输.实际网络运营时,为了提高用户满意度,运营商必须付出额外的成本,分配GPRS专用信道.本文提出了一种使用坎贝尔算法的GPRS无线资源分配算法,考虑了用户期望带宽和小区吞吐量,这两个参量分别代表了用户利益和运营商利益,算法给出了利益妥协结果下需要的GPRS无线信道配置.本文还介绍了另外两种资源分配算法,并进行了性能比较.     

GPRS对语音业务的适应性分析

论述了在GSMPhase2+阶段开发的GPRS标准对实时的语音业务的适应性,由于当前的GPRS标准是对时延不敏感的数据业务优化的,故建议对其进行增强,并将当前及增强后的GPRS的相对性能进行了评价.     

vGPRS: A Mechanism for Voice over GPRS

This paper proposes vGPRS, a voice over IP (VoIP) mechanism for general packet radio service (GPRS) network. In this approach, a new network element called VoIP mobile switching center (VMSC) is introduced to replace standard GSM MSC. Both standard GSM and GPRS mobile stations can be used to receive real-time VoIP service, which need not be equipped with the VoIP (i.e., H.323) terminal capabilities. The vGPRS approach is implemented using standard H.323, GPRS, and GSM protocols. Thus, existing GPRS and H.323 network elements are not modified. Furthermore, the message flows for vGPRS registration, call origination, call release and call termination procedures are described to show the feasibility of our vGPRS system.     

Channel de-allocation schemes for GSM/GPRS networks

Several channel de-allocation schemes for GSM/GPRS（General Packet Radio Service） networks are proposed in this paper. For DRA （Dynamical Resource Allocation） with de-allocation mechanism, if a new voice call arrives and finds that all the channels are busy, then one of the GPRS packets which occupy more than one channel for data transmission may release a channel for the new voice call. This paper presents 5 de-allocation mechanisms, i.e. DA-RANDOM, DA-RICHEST, DA-POOREST, DA-OLDEST and DA-YOUNGEST, to select the GPRS packet for releasing the appropriate channel. Simulation results show that DA-OLDEST achieves the best performance, especially in packets blocking probability, among all the de-allocation schemes. Although the performance of the proposed de-allocation schemes is not significantly different, they are all much better than that of the scheme without de-allocation.     

A bandwidth-on-demand strategy for GPRS

General packet radio service (GPRS) is a global system for mobile communications (GSM) packet data service. In order to efficiently accommodate GPRS traffic while maintaining the desired service quality of GSM calls, we propose a GPRS bandwidth-allocation strategy called the bandwidth-on-demand (BoD) strategy. The BoD strategy is adaptive to the change of traffic conditions, and thus can dynamically adjust the number of channels for GSM and GPRS traffic. Taking the effect of packet dropping due to movements of mobile stations into account, this paper develops an analytical model to study the BoD performance in terms of GSM-call-blocking probability and GPRS-packet-dropping probability.     

The Complementary Use of 3G WCDMA and GSM/GPRS Cellular Radio Networks

The traffic performance of integrated 3G wide-band code division multiple access (WCDMA) and GSM/GPRS network is evaluated. This type of network links two cellular radio systems which have different set of frequency bands and the same coverage size. The base station of 3G WCDMA is installed on an existing GSM/GPRS site. Dual-mode mobile terminals use handoff to establish calls on the better system. The soft handoff or inter-frequency hard handoff occurs when mobile terminals of 3G WCDMA or GSM/GPRS move between two adjacent cells, respectively. The inter-system hard handoffs are used between 3G WCDMA and GSM/GPRS systems. The data rate conversions between different systems, soft handoff region size, multiple data rate multimedia services, and the effect of the mobile terminal mobility on the user mean dwell time in each system are considered in the study. The simulation results demonstrate that a great traffic performance improvement on the complementary use of 3G WCDMA and GSM/GPRS cellular radio networks compared with the use of GSM/GPRS cellular radio networks. When high-data rate transmission is chosen for low-mobility subscribers, both the handoff failure probability, and carried traffic rates increase with the new call generation rate. However, both rates decrease conversely with the increasing new call generation rate as soon as the new call generation rate exceeds a critical value. This causes the integrated networks saturation. The higher mean speed for the mobile terminals produces lower new call blocking probabilities and total carried traffic. The new call blocking probabilities and total carried traffic increase with the size of the soft handoff region.     

Outage Probability in GSM-GPRS Cellular Systems With and Without Frequency Hopping

General packet radio service(GPRS) is designed for transmitting packet data andis supposed to take its radio resource from the pool ofunused channels of GSM voice services. Obviously, theintroduction of GPRS has an impact on the voice services.In this paper, we present a method to calculate theoutage probability of the GSM-GPRS network for bothnon-frequency hopping and frequency hoppingsystems. This method takes into account Rayleighfading, power control (with error), discontinuoustransmission, and frequency hopping (if applied). Theoutage probability of voice services affected by theintroduction of GPRS is discussed. The number ofunused voice channels allocated to GPRS depends on thedifference between the outage level of the existingGSM network and the maximum acceptable level. Thefrequency hopping system can accommodate more GPRStraffic than the non-frequency hopping system. Thepower control error has more impact on systemperformance when more channels are allocated to GPRS.Beyond our expectations, for the non-frequency hoppingsystem, the channels provided for GPRS are not muchdifferent between high channel occupancy and lowchannel occupancy of voice services. In contrast, for thefrequency hopping system, the system can provide morechannels for GPRS at low channel occupancy. The cellservice area decreases by about 10% 20% for eachadditional channel allocated to GPRS.     

基于CPX8216硬件平台的GPRS板间切换的实现

GPRS全称通用分组无线业务,它在改进了现有GSM系统后能实现高速的数据传输。首先对GPRS系统做了简单介绍,然后在此基础上详细介绍了GPRS的板间切换在CPX8216硬件平台上的实现方法。     

On the synergy between adaptive physical layer and multiple-access control for integrated voice and data services in a cellular wireless network

We propose a novel design to exploit the synergy between the multiple-access control (MAC) layer and the physical layer of a cellular wireless system with integrated voice and data services. As in a traditional design, the physical layer (channel encoder and modulator) is responsible for providing error protection for transmitting the packets over the hostile radio channel, while the MAC layer is responsible for allocating the precious bandwidth to the contending users for voice or data connections. However, a distinctive feature of our proposed design is that in the physical layer, a variable-rate adaptive channel encoder is employed to dynamically adjust the amount of forward error correction according to the time-varying wireless channel state such that the MAC layer, which is a reservation-based time-division multiple-access protocol, is able to make informed decisions as to bandwidth allocation. Specifically, based on the channel state information provided by the physical layer, the MAC protocol gives higher priority to users with better channel states. This novel synergistic mechanism between the two protocol layers can utilize the system bandwidth more effectively. The multiple-access performance of the proposed scheme is compared with two baseline systems. The first baseline system consists of the same reservation-based MAC protocol but with a traditional fixed-rate physical layer. The second system consists of the same reservation-based MAC protocol and the same channel adaptive physical layer, but without interaction between the two layers. All three protocols have a request queue, which stores the previous requests that survive the contention but are not allocated information slots. Our extensive simulation results demonstrate that significant performance gains are achieved through the exploitation of the synergy between the two protocol layers.     

ATM traffic management in an LMDS wireless access network

We investigate the capacity of LMDS to support ATM services in the local loop. In particular, we evaluate the performance of a MAC protocol for this system when transporting voice and IP traffic using the VBR and GFR service categories of ATM, respectively. Our results show that the MAC protocol is well suited for voice traffic but in general lacks efficient bandwidth management mechanisms to support the more dynamic bandwidth requirements of IP traffic     

GSM/GPRS分裂信道高效重分配策略

现有GSM/GPRS系统各种信道分裂策略都仅限于话音呼叫,即仅允许分裂信道分配给话音呼叫而不允许分配给包呼叫.因而,当系统没有空信道时,即使可以提供分裂信道,一个新到达的包呼叫也将被阻塞.本文提出的分裂信道重分配策略允许话音呼叫和包呼叫均可获得分裂信道,论文还研究了包呼叫得到分裂信道的条件.研究结果表明,允许将分裂信道分配给新到达包呼叫可以获得更优越的性能;在本文的参数设置下,在门限参数θ＝2/3时,新策略的话音阻塞率和平均包传输时间没有明显恶化,而包阻塞率和平均信道利用率却得以显著改善.     

Analysis of GSM/GPRS Cell with Multiple Data Service Classes

This paper is concerned with the performance modelling and evaluationof a General Packet Radio Service (GPRS) for a wireless Global System forMobile telecommunication (GSM) cellinvolving both voice and multiple class data services under a completepartitioning scheme (CPS). The GPRS is modelled as a system ofaccess and transfer queues in tandem having an external multiple classcompound Poisson bursty traffic with geometrically distributedbatches under first-come-first-served (FCFS) and generalised processor-sharing(PS) scheduling disciplines, respectively. The proposed queueing model isvalid for both uplink and downlink connections and provides multiple classdata services with different arrival rates, interarrival-time squaredcoefficients of variation (SCVs), file (burst) sizes and different PSdiscrimination service levels.Based on the principle of maximum entropy (ME), a product formapproximation is characterised for the two queues in tandem, subject to queueing theoretic mean value constraints. The MEsolution implies a decomposition of the system into individual singleserver building block queues, each of which can be analysed inisolation. Consequently, ME closed form expressions and simulation resultsfor the aggregate state probability together with the marginal mean queuelength and blocking probability are divised to assess the credibility of theME solution and also to study the effect of external GPRS bursty traffic uponthe performance of the wireless cell.