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Congestion Control Strategies in Multi-Access Networks
Abstract
This paper addresses the problematic of congestion control in the radio access interface when considering the allocation of voice and data services over several radio access technologies (RATs). In particular, the GSM/EDGE radio access network (GERAN) and the UMTS terrestrial radio access network (UTRAN) are considered for the evaluation of congestion control strategies. After a congestion situation in the radio access is detected, congestion resolution mechanisms are triggered in order to reduce the overload in the congested RAT(s). In this paper, a framework for the detection and resolution of congestion conditions in a multi-access network is presented. Moreover, three approaches intending to solve congestion situations are proposed and the evaluation of an inter-RAT handover algorithm for solving congestion events in GERAN is also presented.
... [7] and [8], although considering one single RAT. In [9], the authors presented a framework for common congestion control taking into account a scenario where CDMA and TDMA technologies were deployed. Some congestion resolution methodologies were presented taking advantage of the CRRM concepts. ...
... In this context, overload situations may occur due to the excessive resource sharing among data users over the same timeslot. Bearing this in mind, it was proposed in [9] that the reduction factor (RF) could be useful to account for the congestion effect of timeslot sharing among users. This parameter takes values between 0 and 1, meaning a high timeslot reuse in the former and a low timeslot reuse in the latter. ...
... In a multi-RAT environment, to perform a VHO should be the preferred option since it may solve the congestion situation without degrading the quality perceived by users [9]. However, given a scenario where both GERAN and UTRAN RATs are in a congestion state, solely performing VHO among RATs will not solve the congestion. ...
Among the common radio resource management (CRRM) functions that are responsible for the proper allocation of resources in a multi-access network, congestion control is the one devoted to overcome potential QoS failures due to the inherent dynamics of the network. In this paper we address the problem of congestion control in a scenario considering the GSM/EDGE radio access network (GERAN) and the UMTS terrestrial radio access network (UTRAN). In particular, we face the problem where the two available radio access technologies (RATs) undergo simultaneous congestion situations. For this case, a congestion resolution scheme based on vertical (inter-system) handover (VHO) jointly with a bit-rate reduction (BRR) scheme is proposed and evaluated for a mixed services scenario considering voice and data users.
... B RADIO ACCESS TECHNOLOGY DELAYS AND CONGESTION: RATs, which includes WLAN, DSRC, LTE, and 5G according to [201], covers the boundaries of wireless technology that enables devices to access the network. On the other hand, delays are evident through the time delays between the transmission and reception of a data packet in a network [202]. Some of these days within the network can lead to congestion of the network. ...
p>The escalating growth of vehicles has amplified the complexity of Vehicle Ad-hoc Networks (VANETs), necessitating innovative strategies to combat communication delays and disruptions. In this study, we covered a literature review from 2009 to 2023 where we present a comprehensive exploration of solutions by integrating Software-Defined Networking (SDN), Programming Protocol-independent Packet Processors (P4), and Service Function Chaining (SFC). Our research addresses the core challenges of VANETs, emphasizing the specific problem of communication delays.
We conducted an in-depth analysis of SDN’s application in VANETs, showcasing its potential to enhance network efficiency and adaptability. Additionally, we delve into the practical implementation of P4 architecture in traffic management and multihoming environments, elucidating its pivotal role in improving VANET performance. Simultaneously, we explore the intricacies of SFC and its support for services and policies in VANETs.
Our study reveals novel approaches to mitigate delays in VANETs, presenting valuable insights for both researchers and practitioners. By integrating SDN, P4 architecture, and SFC in a multihoming environment, our research not only advances the understanding of VANET challenges but also provides practical and implementable solutions for achieving efficient and low-latency vehicular communication networks. This work do not only contributes to the academic discourse but also holds significant promise for real-world applications, marking a pivotal step towards the future of seamless vehicular communications.</p
... When overload is encountered in one or more RATs, the JCC returns the congested RAT(s) quickly and controllably back to their targeted thresholds using new congestion resolution methodologies such as VHO. In [78], X. Gelabert et al. present a framework for JCC taking into account a scenario where CDMA and TDMA technologies were deployed. Some congestion resolution methodologies are presented taking advantage of the JRRM concepts. ...
... Visando suportar de maneira satisfatória tais demandas, bem como disponibilizar novos recursos para as novas modalidades de aplicações, a indústria de telecomunicação defronta-se com a necessidade de buscar novos mecanismos e tecnologias para as várias linhas de trabalho na área de Gerenciamento de Recursos de Rádio (Radio Resource Management -RRM) [1]. Estas linhas abrangem funcionalidades como o Controle de Admissão (Admission Control ou CAC) [2], Controle de Congestionamento [3], Controle de Potência (Power Control ou Power Balancing) [1], Alocação de Canais (Dynamic Channel Allocation-DCA) [4], Handover [6] e Modulação Adaptativa (Adaptive Modulation) [5]. Uma implementação eficiente de tais mecanismos possibilita um aumento da eficiência na utilização da banda de frequência utilizada pelos sistemas, bem como a redução de gastos das operadoras e consequentemente um barateamento da disponibilização dos serviços ao usuário final. ...
The growth of the telecommunications systems utilization and the introduction of the Third Generation Cell-Phone technologies motivate the industry to search for new alternatives to manage the traditional radio infrastructure. Aiming to supply this demand, the industry is confronted with the necessity of finding new mechanisms and technologies to the different work lines in Radio Resources Management area. This paper aims to present the main research lines into RRM area, besides the major attributions of each line. Resumo. O aumento da utilização dos sistemas de telecomunicações e a introdução dos chamados sistemas celulares de terceira geração (3G) levam a indústria a buscar por novas alternativas para gerir sua infra-estrutura de rádio tradicional. Visando atender a tal demanda, a indústria defronta-se com a necessidade de buscar novos mecanismos e tecnologias para as várias linhas de trabalho da área de Gerenciamento de Recursos de Rádio. Este artigo visa apresentar as principais linhas de trabalho da área de Gerenciamento de Recursos de Rádio, bem como as principais atribuições de cada linha.
This work addresses the problem of radio access congestion control and resource allocation in scenarios where multiple available radio access technologies (RATs) support a wide range of services over a given coverage area. A key issue in these networks is selecting the most appropriate RAT at a call/session establishment according to some specified user/operator criteria. In this sense, a wide range of high-level policies can be defined, providing the most favorable resource allocation. Regardless of having efficient RAT selection policies, which may ensure some initial quality of service (QoS) requirements, intrinsic network dynamics (e.g., mobility, user activity, and interference rise) can cause potential QoS failures, leading to a degraded network performance and, hence, radio access congestion. This work is devoted to the study of the impact of radio access congestion on a number of RAT-selection policies. Consequently, a congestion probability (CP) model is developed to capture the statistical behavior of radio access congestion events. In addition, a general Markovian framework is adopted to evaluate the allocation of multiple services into multiple RATs by means of high-level policy definitions. Specific RAT-selection policies are defined according to several criteria, and their performances are evaluated in a time-division multiple-access (TDMA)/wideband code-division multiple-access (WCDMA) multi-RAT scenario supporting voice and data services. Moreover, the use of CP information as a possible allocation principle for RAT selection is also evaluated, which, in the assumed scenario, results in the most favorable allocation policy.
This work takes as a reference the scenario of heterogeneous radio access networks where several radio access technologies (RATs) coexist and cooperate providing a range of services over a specific coverage area. In this context, an appropriate RAT must be selected upon each user request in order to provide the specified quality of service (QoS) level for the requested service. Despite of having an efficient RAT selection mechanism, the intrinsic network dynamics may pose some risk on the QoS guarantees in each RAT which may not be met thus leading to a degraded network performance. In such situations, the network undergoes so-called radio access congestion situations. In this work, a statistical characterization of radio access congestion is provided for TDMA and WCDMA based systems. Furthermore, the impact of several representative RAT selection policies is evaluated in terms of their obtained congestion probability. Numerical results conclude that a proper knowledge of congestion information can be used as a relevant input for RAT selection specification.
The ongoing introduction of GPRS services in existing GSM networks by mobile network providers raises the ques-tion of the best strategy to partition the available cell ca-pacity. The paper describes three different strategies – com-plete partitioning, partial sharing and complete sharing. An analytical call/burst level model of one cell of a homoge-neous multiservice GSM/GPRS network is used to investi-gate these strategies with respect to important performance measures like new and handover blocking probabilities, sys-tem utilization and mean data rates of the services. Numer-ical results show, that the complete sharing strategy in con-nection with the proposed admission policy achieves a high system utilization while even for low priority data connec-tions some minimum quality of service is guaranteed.
For a regular array of hexagonal cells in a suburban outdoor
environment, we examined resource allocation schemes in the radio
network controller (RNC) for the uplink and downlink in a UMTS network.
In the uplink, the noise rise is the parameter of choice. In the
downlink, the power for different data rates and the connection as a
whole serves as the means to control the network. Allocating this
resource in admission and congestion control, the throughput of a packet
service with variable data rate was optimised
Myths about congestion control are examined, and an explanation of why the trend toward cheaper memory, higher-speed links, and higher-speed processors has intensified the need to solve the congestion problem is provided. A number of proposed solutions are described, and a classification of congestion problems as well as their solutions is presented. The reasons why the problem is so difficult are identified, and the protocol design decisions that affect the design of a congestion control scheme are discussed. The author's recent proposals, namely, timeout-based congestion control, a DECbit scheme and a delay-based scheme for congestion avoidance are described, and areas for future research are suggested.< >
The key feature of future mobile communication systems is the ability to deliver wideband and high bit-rate multimedia services alongside the traditional radio services such as voice, messaging and slow rate data. The broad range of services expected to be supported can be divided into different Quality of Service (QoS) classes. However, the provision of such mobile multimedia services under QoS guarantees will not be possible without a utilization of the air interface resources by means of Radio Resource Management (RRM) strategies that ensure the target QoS, the planned coverage area and that offer a high system capacity. Under this framework, the book focuses on the RRM concepts, including the theoretical background that serves as a basis for the description of specific RRM algorithms. The RRM problem for UMTS is presented, and more specifically, for the FDD mode, which is based on a WCDMA scheme. More specifically, the different aspects that are covered include: Introduces the mobile communications sector and UMTS, including the evolution towards 4G systems, with an overview of the QoS concept which is key for the definition of RRM strategies. Offers a detailed description of the radio interface in UMTS, as the basis for the implementation of RRM strategies. Provides the fundamental concepts related with the development of RRM strategies in WCDMA networks. Analyses particular RRM algorithms in a variety of scenarios, trying to identify the key parameters and factors that influence their performance. Explores the evolution of UMTS towards Beyond 3G systems and the concept of Common RRM in heterogeneous networks with the aid of some algorithm examples. This comprehensive title is essential reading for engineers and managers in radio engineering departments of UMTS network operators and UMTS equipment manufacturers. It will also prove insightful to researchers in the field of 3G and Beyond 3G systems and academics in any of these areas.
The heterogeneous network concept offers a flexible architecture that allows an efficient utilization of radio resources by means of Common RRM strategies that ensure a coordinated management of the resource pools in each Radio Access Network. In this context, this paper discusses different strategies for initial RAT selection as one of the key CRRM strategies. A general framework for the definition of policy- based RAT selection strategies is proposed and some specific examples are evaluated by means of simulations.
This paper presents an analytical framework to discriminate the impact that the neighbouring cells have over a reference cell in a multicellular W-CDMA scenario, based on establishing the mutual relationships between cells in terms of uplink cell load factor and downlink transmitted power. The derivatives of these two parameters, with respect to the neighbouring cells, are taken as a measurement of the interactions between cells. Based on this analytical framework, a multicell load control algorithm is proposed and compared with two other algorithms by means of simulations.
Next generation wireless communication systems will bring new architecture concepts, new spectrum allocation policies and smart resource management in a multi-network environment [ R. Berezdivin, et al., March 2002]. Within this context the IST DRiVE project [IST DRiVE Project Website, http://www.ist-drive.org/] aims at enabling a spectrum-efficient high-quality wireless IP in a heterogeneous multi-radio environment to deliver in-vehicle services. This paper assumes a multi-network scenario comprising GPRS and UMTS radio access networks (RAN) and proposes several schemes for controlling and distributing the network traffic over these two RANs, increasing the spectrum efficiency of the whole system by ensuring that mobile terminals are served by the optimum radio access technology available. This is achieved by assigning a cost to each service that the network can provide, taking into account both system load and system resource availability, and enabling the mobile terminal to select the most efficient RAN, retaining the quality the user asks for. The results show that a gain, in terms of percentage of satisfied users, of more than 15% can be obtained by the multi-network system compared to the case of no traffic distribution process, thus leading to a more efficient spectrum usage.
The WCDMA air interface was initially designed to support a wide variety of services with different QoS requirements having a maximum bit rate of 2 Mb/s. In order to satisfy the future service and application needs several technical enhancements are being studied and standardized for WCDMA in 3GPP. Even with evolved WCDMA, there is a need for another public wireless access solution to cover the demand for data-intensive applications and enable smooth online access to corporate data services in hot spots. This need could be fulfilled by WLAN together with a high-data-rate cellular WCDMA system. WLAN offers an interesting possibility for cellular operators to offer additional capacity and higher bandwidths for end users without sacrificing the capacity of cellular users. The evolved WCDMA air interface will provide better performance and higher bit rates than basic WCDMA, based on first releases of the specifications. Eventually, evolution may not be the answer to all the needs, and come revolutionary concepts need to be considered. However, before some future wireless system can be regarded as belonging to 4G it must possess capabilities that by far exceed those of 3G systems like WCDMA. Judging from an application and services point of view, one distinguishing factor between 3G and 4G will still be the data rate. We could define that 4G should support at least 100 Mb/s peak data rates in full-mobility wide area coverage and 1 Gb/s in low-mobility local area coverage. Other possible characteristics of 4G need to be further studied.
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Analysis and Simulation of Wireless and Mobile Systems rs Interactive = 100 (before CC)
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Modeling, Analysis and Simulation of Wireless and Mobile Systems
rs Interactive = 100 (before CC)