IP-based Radio Access Networks Research Articles

Congestion Avoidance in IP Based CDMA Radio Access Network

CDMA is an important air interface technologies for cellular wireless networks. As CDMAbased cellular networks mature, the current point-to-point links will evolve to an IP-based Radio Access Network (RAN). mechanisms must be designed to control the IP Radio Access Network congestion. This Paper implements a congestion control mechanism using Router control and channel control method for IP-RAN on CDMA cellular network. The Router control mechanism uses the features of CDMA networks using active Queue Management technique to reduce delay and to minimize the correlated losses. The Random Early Detection Active Queue Management scheme (REDAQM) is to be realized for the router control for data transmission over the radio network using routers as the channel. The channel control mechanism control the congestion by bifurcating the access channel into multiple layer namely RACH, BCCH and DCH for data accessing. The proposed paper work is realized using Matlab platform.

Experiments on Handover Using Combination of Bicast and Forwarding of IP Packet for Future IP-Based RANs

This paper proposes a handover method that uses a combination of bicast and forwarding (BIFO) of IP packets to achieve a short handover delay. BIFO achieves a lower amount of IP packet traffic in the backhaul for future IP-based radio access networks (RANs) than the bicast only method. To validate the effect of the proposed BIFO, we implement prototype experimental equipment comprising a RAN_access router (RAN_AR), Node Bs associated with a radio control server (RCS), and user equipment (UE) including a controller. The experimental results show that BIFO achieves a shorter handover delay than the conventional bicast method or forwarding method by taking advantage of the respective merits of bicast and forwarding. The results also confirm that BIFO achieves the handover delay time in the control plane of approximately 10-20msec.

IP-based radio access network implementation cost vs. network security trade-off

The primary motivation for the evolution from proprietary networks to Internet Protocol (IP)-based radio access network (RAN) systems is cost savings in terms of both capital expenditures (CAPEX) and operating expenditures (OPEX). This evolution, however, given the open network environment, introduces new security threats. Such threats can result in significant potential costs that need to be mitigated through additional investments in security solutions. Finding the optimal balance between investment and potential security risk is a complex endeavor. This paper presents rendezvous point (RP), a method to find the optimal point for a balanced security solution. © 2007 Alcatel-Lucent.

IP-based radio access network implementation cost vs. network security trade-off

The primary motivation for the evolution from proprietary networks to Internet Protocol (IP)-based radio access network (RAN) systems is cost savings in terms of both capital expenditures (CAPEX) a...

Connectivity, performance, and resiliency of IP-based CDMA radio access networks

IP-based radio access networks (RAN) are expected to be the next generation access networks in UMTS and CDMA networks. The question of connectivity, i.e., how best to connect base stations to the radio network controllers (RNC) in an IP-based RAN, has not been addressed by researchers. Furthermore, given a connection configuration, an RNC selection algorithm that assigns an incoming call to an RNC is also necessary. This paper examines RAN connectivity and its impact on the performance and resiliency of the wireless network using different RNC selection algorithms. For homogeneous networks, we show that the proposed min-load-1 algorithm, which allows at most one hard handoff in order to accommodate each incoming call request, delivers performance close to the optimal algorithm. We also show that allowing a few base stations to connect to two RNCs (a 10 percent increase in the number of links in our network) results in resiliency to RNC failures that is comparable to the resiliency of RANs with full-mesh connectivity. Finally, for heterogeneous networks, we show that the min-load-k algorithm (with at most k hard handoffs per call) is effective in handling load imbalances. These results provide strong motivation for deploying IP-based RAN, as they suggest that enhancing current point-to-point RAN with few additional links and allowing a few hard handoffs to accommodate incoming calls can result in significant gains in performance and resiliency

What a mesh! An architecture for next-generation radio access networks

With fourth-generation wireless technologies envisioned to provide high bandwidth for content-rich multimedia applications, next-generation mobile communication systems are well poised to lead the technology march. Incumbent with the new technology is the challenge of providing flexible, reconfigurable architectures capable of catering to the dynamics of the network, while providing cost-effective solutions for service providers. In this article we focus on IP-based radio access network architectures for next-generation mobile systems. We provide an insight into wireless mesh-based connectivity for the RAN network elements - using short high-bandwidth links to interconnect the network entities in a multihop mesh network for backhauling traffic to the core. A generic self-similar fractal topology, using optical wireless transmission technology, is described. We study the performance of the architecture and conclude that mesh-based architectures are well suited to provide highly scalable, dynamic radio access networks with carrier-class features at significantly low system costs.

Congestion control policies for IP-based CDMA radio access networks

As CDMA-based cellular networks mature, the current point-to-point links used in connecting base stations to network controllers evolve to an IP-based radio access network (RAN) for reasons of lower cost due to statistical multiplexing gains, better scalability and reliability, and the projected growth in data applications. In this paper, we study the impact of congestion in a best-effort IP RAN on CDMA cellular voice networks. We propose and evaluate three congestion control mechanisms, admission control, diversity control, and router control, to maximize network capacity while maintaining good voice quality. We first propose two new enhancements to CDMA call admission control that consider a unified view of both IP RAN and air interface resources. Next, we introduce a novel technique called diversity control that exploits the soft-handoff feature of CDMA networks and drops selected frames belonging to multiple soft-handoff legs to gracefully degrade-voice quality during congestion. Finally, we study the impact of router control where an active queue management technique is used to reduce delay and minimize correlated losses. Using simulations of a large mobile network, we show that the three different control mechanisms can help gracefully manage 10-40 percent congestion overload in the IP RAN.

Achieving seamless mobility in IP-based radio access networks

A handover in any IP-based mobile network is a complex procedure. Typically, it takes quite a long time before the new access router gets the parameters describing the flow states associated with an incoming mobile node. It may even be that the new access router does not have enough resources to support the rerouted flows. Thus, it is crucial to select from several candidate access routers the one that best fits the mobile node's requirements. This article describes the candidate access router discovery protocol, which can be used to select a suitable new access router. We also address the context transfer architecture that makes use of the candidate access router discovery protocol and aims to reduce the time required to recover flow descriptor parameters. Finally, we discuss how the two protocols can intemperate to achieve seamless handovers.

Terminal-centric view of software. reconfigurable system architecture and enabling components and technologies

Reconfigurable radio in Europe is rapidly gaining momentum and becoming a key enabler for realizing the vision of being optimally connected anywhere, anytime. At the center of this exciting technology is the reconfigurable terminal that will move across different radio access networks, adapting at every instant to an optimum mode of operation. This will require coordinated reconfiguration management support from both the terminal and the network, but the terminal will inherit a significant part of this intelligence. This article focuses on a novel reconfigurable terminal architecture that advances the state of the art and encompasses the overall protocol stack from the physical to application layer in IP-based radio access networks. The proposed architecture is composed of a terminal reconfiguration management part and enabling middleware technologies like the complementary Distributed Processing Environment and agent platforms, flexible protocol stacks that can flexibly be interchanged to support different wireless technologies and associated mechanisms, and finally, object-oriented reconfigurable RF and baseband components. The work presented in this article is conducted in the context of the IST projects SCOUT (www.ist-scout.org) and TRUST (www4.in.tum.de/-scout/trust webpage/spl I.bar/src/ trust frameset.html) of the European 5th Framework Program.

Real-time packet scheduling in next generation radio access system

All IP-based radio access network enable packet-oriented connections to offer real-time applications. Radio access networks must provide efficient radio management for data session establishments because of scarce radio resources. In this paper, we present three real-time scheduling algorithms to support quality-of-service at IP-based radio access networks. The real-time generic scheduling (RTGS) algorithm applies the functionalities of the radio management framework to establish new data sessions for real-time service requests. The real-time bandwidth scheduling (RTBS) algorithm implements the early-deadline-first scheme to do the schedulability analysis and to schedule the data sessions to reduce power consumption. The RTBS algorithm can decrease the power consumption more than can RTGS. Based on the RTBS mechanism, we design the real-time code scheduling (RTCS) algorithm. In this algorithm, we apply the dynamic code assignment scheme to increase the probability of schedulable sessions and improve the radio resource utilization. Experimental results show that RTCS outperforms RTBS and, in turn, RTBS outperforms RTGS.

Quality of service in third-generation IP-based radio access networks

Currently, the radio access network (RAN) in code division multiple access (CDMA)-based third-generation (3G) technologies (CDMA2000 and Universal Mobile Telecommunications Service [UMTS]) is based on asynchronous transfer mode (ATM). By using the quality-of-service (QoS) guarantees provided by ATM technology, these 3G systems can efficiently transport time-sensitive user traffic to different network elements. An effort is currently under way in several wireless standards bodies to convert this connection-oriented ATM-based RAN to a connectionless Internet protocol (IP) network. Such a migration would converge the core and radio access networks and hence yield cost savings and ease of maintenance. It is also apparent that such a migration imposes new challenges to be solved on the QoS front since IP is, predominantly, a best-effort transport mechanism. In this paper, we explore the QoS support provided by 3rd Generation Partnership Project 2 (3GPP2) standards and discuss several possibilities for using IP transport without degrading the QoS experienced by different traffic types. We provide a detailed description on the DiffServ approach and how it can be used together with multiprotocol label switching (MPLS) technology to provide the QoS guarantees in an IP-based RAN. Finally, we briefly describe how the QoS framework discussed for CDMA2000∗ can be applied to UMTS based networks.