High Speed Packet Access Networks Research Articles

The Right Time: Reducing Effective End-to-End Delay in Time-Slotted Packet-Switched Networks

Modern access network technologies like Long Term Evolution (LTE) and High Speed Packet Access (HSPA) use time-slotting mechanisms to optimize resource sharing and overall network performance. In time-slotted networks, the one-way delay of all packets in a packet stream depends on the absolute point in time when the first packet of the stream is sent. With appropriate feedback signals, applications can exploit this effect to reduce their effective end-to-end delay. Time-critical applications such as real-time sensor data acquisition or voice-over-IP (VoIP) communications can shift their acquisition interval in order to adapt to the network timing. Information about the actual time-slotting periods can be gathered by active network measurements or through implementation of cross-layer information exchange. In this paper, a method is proposed to determine the optimum send time for particular destinations and to support applications in adjusting their send time accordingly. Theoretical findings are supported by the offline analysis of measurement data and by a proof-of-concept implementation that confirms the feasibility and effectiveness of the proposed solution in operational LTE and HSPA networks.

Research and Simulation on Wireless Packet Scheduling Scheme Based on High-Speed Packet Access Network

The efficiency of high speed packet access (HSPA) systems is mainly based on Packet Scheduling Scheme which will be the key to influencing on the system performance and ensuring the service quality for the users. In this paper, we introduce a three step packet scheduling scheme to provide quality of services (QoS) guaranteed for high speed uplink packet access. Then, we proposed an improved packet scheduling algorithm based on QoS parameter for mixed service applications in order to meet the actual QoS needs of the different systems. This algorithm calculated the scheduling priority based on the comprehensive factors, including the queuing status of each user, QoS requirements and the sum of speeds on each channel. The simulation results show that the performance efficiency of HSPA systems employed proposed algorithm is superior compared to the conventional PF and M-LWDF algorithm in average packet drop and average cell throughput.

Evaluation of the UTRAN (HSPA) performance in different configurations in the presence of M2M and online gaming traffic

AbstractIn this paper, performance analysis of a High Speed Packet Access network in the presence of machine‐to‐machine (M2M) and online gaming traffic is described. The evaluation was performed in a live network, using a number of mobile phones to generate additional traffic load. One Node B, with different configurations, was used throughout the experiments. The main areas of impact are identified, and similar underlying mechanisms are later recognised through deployment of a commercial large‐scale M2M application. The paper describes the key findings of the analysis of five test cases from the network performance aspect. It further associates perceived network behaviour with the end‐user experience in terms of the average delays. At the end, a comparison with the observed impacts of a live M2M application is given, and the main issues highlighted, together with a discussion on possible solutions. Copyright © 2013 John Wiley & Sons, Ltd.

Support of mobile TV over an HSPA network

This paper describes a quality of service (QoS) implementation in the UMTS Terrestrial Radio Access Network (UTRAN) to commercialize mobile television (TV) services with current High Speed Packet Access (HSPA) commercial devices, which do not support a streaming traffic class as defined by the 3rd Generation Partnership Project (3GPP). This implementation allows the mobile operators to offer a high quality of service for the end user in terms of reducing the need for re-buffering during the mobile TV session, while minimizing the impact of the service on the overall radio cell capacity. System level simulations relying on a Tier 1 operator use case have been generated to quantify the benefits streaming users experience due to this QoS implementation in the presence of background traffic in the same radio cell. The impact in terms of radio cell capacity is also evaluated.

Performance Enhancement due to the TNL Congestion Control on the Simultaneous Deployment of both HSDPA and HSUPA

the main focus of the work presented in this paper is to analyze the effect of the Transport Network Layer (TNL) congestion control on the High Speed Packet Access (HSPA) performance. The TNL and in particular the Iub link needs to be carefully dimensioned. Firstly because it has significant impact on the end-to-end and network performance and secondly due to the high number of required links in the network, the Iub is a major cost factor for the network operators. The congestion control function works together with the air interface scheduler and Hybrid Automatic Repeat Request (HARQ) in order to control the offered load to the TNL network. In this manner, the data flow over the TNL is adequately adapted to the user’s air interface data rate and to the available TNL capacity avoiding congestion in the transport network. In addition, the paper focuses as well on the effects of the simultaneous deployment of both High Speed Downlink and Uplink Packet Access (HSDPA & HSUPA). This is done by comparing the results from deploying HSDPA or HSUPA separately in the system against the simultaneous deployment of both (To the best of our knowledge, there are only few publications in which this has been investigated, especially in combination with the Congestion Control). The reason for such a comparison is to highlight the effects that appear when both are deployed together, since most of the previous studies were focusing only on either HSDPA or HSUPA, whereas the final goal is to use both together in one system. The simulation results presented in this paper confirm that the congestion in the transport network can be controlled in such a way that the available TNL capacity can be effectively utilized and hence the performance of HSPA network can be significantly improved in all aspects. In the ComNets TZI working group at the university of Bremen, a number of projects focusing on the TNL dimensioning and TNL features development for the HSPA network are being worked on [14, 15, 16, 17, 18, 19 and 20].

Novel Radio Link Buffer Management Schemes for End-User Multi-class Traffic in High Speed Packet Access Networks

The requirement to provide multimedia services with QoS support in mobile networks has led to standardization and deployment of high speed data access technologies such as the High Speed Downlink Packet Access (HSDPA) system. HSDPA improves downlink packet data and multimedia services support in WCDMA-based cellular networks. As is the trend in emerging wireless access technologies, HSDPA supports end-user multi-class sessions comprising parallel flows with diverse Quality of Service (QoS) requirements, such as real-time (RT) voice or video streaming concurrent with non real-time (NRT) data service being transmitted to the same user, with differentiated queuing at the radio link interface. Hence, in this paper we present and evaluate novel radio link buffer management schemes for QoS control of multimedia traffic comprising concurrent RT and NRT flows in the same HSDPA end-user session. The new buffer management schemes—Enhanced Time Space Priority (E-TSP) and Dynamic Time Space Priority (D-TSP)—are designed to improve radio link and network resource utilization as well as optimize end-to-end QoS performance of both RT and NRT flows in the end-user session. Both schemes are based on a Time-Space Priority (TSP) queuing system, which provides joint delay and loss differentiation between the flows by queuing (partially) loss tolerant RT flow packets for higher transmission priority but with restricted access to the buffer space, whilst allowing unlimited access to the buffer space for delay-tolerant NRT flow but with queuing for lower transmission priority. Experiments by means of extensive system-level HSDPA simulations demonstrates that with the proposed TSP-based radio link buffer management schemes, significant end-to-end QoS performance gains accrue to end-user traffic with simultaneous RT and NRT flows, in addition to improved resource utilization in the radio access network.

Dynamic Reservation Scheme of Physical Cell Identity for 3GPP LTE Femtocell Systems

A large number of phone calls and data services will take place in indoor environments. In Long Term Evolution (LTE), femtocell, as a home base station for indoor coverage extension and wideband data service, has recently gained significant interests from operators and consumers. Since femtocell is frequently turned on and off by a personal owner, not by a network operator, one of the key issues is that femtocell should be identified autonomously without system information to support handover from macrocell to femtocell. In this paper, we propose a dynamic reservation scheme of Physical Cell Identities (PCI) for 3GPP LTE femtocell systems. There are several reserving types, and each type reserves a different number of PCIs for femtocell. The transition among the types depends on the deployed number of femtocells, or the number of PCI confusion events. Accordingly, flexible use of PCIs can decrease PCI confusion. This reduces searching time for femtocell, and it is helpful for the quick handover from macrocell to femtocell. Simulation results show that our proposed scheme re- duces average delay for identifying detected cells, and increases network capacity within equal delay constraints. The 3rd Generation Partnership Project (3GPP) is work- ing on the standardization of asynchronous communication systems. This technology is being enhanced gradually en- suring higher user data rate, bigger system capacity, and lower cost. The wideband CDMA (WCDMA) system is standardized with 3GPP release 99/4 which is being de- ployed in the world. Release 5 is related to High Speed Downlink Packet Access (HSDPA), and it improves the downlink packet transmission speed theoretically up to 14.4 Mbps. High Speed Uplink Packet Access (HSUPA) is enhanced up to 5.76 Mbps in uplink, and it is standardized with the Release 6. We simply mention both HSDPA and HSUPA as High Speed Packet Access (HSPA). In release 7, High Speed Packet Access Evolution (eHSPA, HSPA+) is standardized. eHSPA is based on the HSPA network with a simple upgrade, and it supports more bandwidth efficiency and lower latency. The maximum data rate is 28.8 Mbps in downlink and 11.5 Mbps in uplink (1). How- ever, users still require further system improvements. The technology is dramatically enhanced in release 8, where the standard of Long Term Evolution (LTE) is currently being established. The main objectives of LTE are higher data rates, lower latency, increased capacity, enhanced coverage, and an optimized system for the packet switching network (2). LTE also considers a femtocell, which is referred to as a home base station for an indoor coverage extension and overall network performance enhancement (3). Recently, LTE-Advanced standard targeting of 1Gbps for low mobil- ity is being discussed in release 9. We look into general features and requirements of fem- tocells. Important issues related to access control are de- scribed, followed by our contributions and organization of the paper.

Efficient peer-to-peer file sharing in 3G networks

In 3G networks upgraded with high speed packet access (HSPA) technology, the high access bandwidth and advanced mobile devices make it applicable to share large files among mobile users by peer-to-peer applications. To receive files as quickly as possible is essential for mobile users in file sharing applications, since they are subject to unstable signal strength and battery failures. While many researches present peer-to-peer file sharing architectures in mobile environments, few works focus on decreasing the time spent in disseminating files among users. In this paper, we present an efficient peer-to-peer file sharing design for HSPA networks called efficient file sharing (EFS) for 3G networks. EFS can decrease the dissemination time by efficiently utilizing the upstream-bandwidth of mobile nodes. It uses an adaptive rearrangement of a node’s concurrent uploading transfers, which causes the count of the node’s concurrent uploading transfers to lower while ensuring that the node’s upstream-bandwidth can be efficiently utilized. Our simulations show that, EFS achieves much less dissemination time than other protocols including Bullet Prime and a direct implementation of BitTorrent for mobile environments.

Peer-to-Peer Based Fast File Dissemination in UMTS Networks

In UMTS (universal mobile telecommunications system) networks upgraded with HSPA (high speed packet access) technology, the high access bandwidth and advanced mobile devices make it applicable to share large files among mobile users by peer-to-peer applications. To receive files quickly is essential for mobile users in file sharing applications, mainly because they are subject to unstable signal strength and battery failures. While many researches present peer-to-peer file sharing architectures in mobile environments, few works focus on decreasing the time spent in disseminating files among users. In this paper, we present an efficient peer-to-peer file sharing design for HSPA networks called AFAM — Adaptive efficient File shAring for uMts networks. AFAM can decrease the dissemination time by efficiently utilizing the upload-bandwidth of mobile nodes. It uses an adaptive rearrangement of a node's concurrent uploads, which causes the count of the node's concurrent uploads to lower while ensuring that the node's upload-bandwidth can be efficiently utilized. AFAM also uses URF — Upload Rarest First policy for the block selection and receiver selection, which achieves real rarest-first for the spread of blocks and effectively avoids the “last-block” problem in file sharing applications. Our simulations show that, AFAM achieves much less dissemination time than other protocols including BulletPrime and a direct implementation of BitTorrent for mobile environments.