3G HSPA基地台使用NG-SDH為光纖傳輸模式的研究與實測

This chapter contains sections titled: Introduction High Speed Downlink Packet Access High Speed Uplink Packet Access Implementation Issues

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.

The high-speed downlink packet access (HSPDA) system is expected to effectively support voice services when Release 7/8 features are adopted in the system. In this letter, we point out that a voice packet can be transmitted at a lower power level than normal in the HSDPA network. We propose a power allocation scheme that adjusts the transmission power of voice packets optimally and allocates the remaining transmission power to data services in order to improve data throughput. The proposed power allocation is analyzed with a Rayleigh fading channel model and compared to conventional fixed power allocation.

In this paper, we analyze the capacity of Circuit Switched Voice over High Speed Packet Access (HSPA) (CSoHS), using a Release 7 HSPA system that supports Continuous Packet Connectivity (CPC). On the Downlink (DL), we modeled the power consumption of the Fractional Dedicated Physical Channel (F-DPCH) and the Enhanced DCH Hybrid ARQ Indicator Channel (E-HICH). On the uplink (UL), we modeled the overhead channels, High Speed Dedicated Physical Control Channel (HS-DPCCH) and Enhanced DCH Dedicated Physical Control Channel (E-DPCCH). Our results show voice capacity gains that are achievable with CPC. We also show the gains in downlink voice capacity that are achievable by using the MAC-segmentation feature, introduced in Release 7.

Only best-effort traffic was supported by traditional packet switching networks, but newer applications need network services that allow an end-client to transport data with performance guarantees. The choice of packet-scheduling algorithm used at switching nodes is crucial in providing Quality of Service (QoS). This paper proposes a downlink packet scheduling algorithm for QoS provisioning in High Speed Downlink Packet Access (HSDPA) based UMTS networks. In HSDPA, a single logical channel is shared amongst multiple contending users. Besides better link utilization, scheduling disciplines seek to achieve fair allocation of this shared resource. However, these two criteria can potentially be in conflict. The scheduling algorithm proposed in this paper, Wireless Fair High Speed Scheduling, addresses this conflict. The basic idea is to allocate the wireless channel fairly amongst users, even during short time scales, according to their data rate requirements. Simulation results show that the proposed scheduling algorithm provides better link utilization, as well as long-term and short-term fairness amongst users, even under heavy load conditions.

High speed downlink packet access (HSDPA) is specified in the 3GPP to cope with the increasing demand of high-speed Internet-based multimedia services. HSDPA is based on techniques such as base station scheduling, adaptive modulation and coding, hybrid automatic repeat request, and advanced receiver design. This work presents system-level simulation results on the HSDPA performance to reveal the effects of user equipment (UE) capabilities such as the maximum number of multicodes and receive diversity. The results show that a 15- and 10-multi-code UE and the receive diversity significantly improve the cell capacity. Experiments using the HSDPA test-beds are conducted to investigate the true HSDPA performance. Furthermore, TCP/IP-level simulation results show the application-level throughput, i.e. end-user throughput, in the HSDPA system. The results indicate that reduction of the round trip time, a higher uplink data rate, and low uplink block error rate are required to achieve the high TCP-level throughput.

Simple wireless scheduling techniques, such as maximum carrier-to-interference ratio (Max. C/I) or round robin (RR), fail to take into account all aspects of quality of service (QoS) provisioning. The fundamentals of evolutionary computation (genetic algorithms) and conventional wireless scheduling techniques are combined and the weaknesses of the existing known techniques are exploited to propose a novel hybrid genetic packet scheduler (HGPS) for high speed downlink packet access (HSDPA). The proposed HGPS outperforms the Max. C/I packet scheduler in terms of total delivered throughput within low delay thresholds.

In this paper, we consider a low-complexity multiuser detection for downlink of high speed packet access (HSPA) of universal mobile telecommunications system (UMTS). Instead of attempting to perform maximum likelihood (ML) detection of all users in multiple cells, which is impractical for battery powered mobile receiver, we utilize interference cancelled chips obtained from iterative linear minimum mean square error (LMMSE) estimation to perform a near ML detection in a reduced dimensional system. As a result, the worst case complexity of the detection process, achieved by the closest lattice point search (CLPS), is bounded to a controllable level irrespective of multipath spans. Furthermore, by exploiting the LMMSE estimate in tightening the hypersphere condition of the CLPS algorithm so called sphere decoding, we achieve significant improvement in search complexity. From simulations on realistic downlink communication scenario in HSPA systems, we show that the proposed method offers substantial performance gain over conventional receiver algorithms with reasonable complexity.

The provision of data services in 3G systems requires spectral efficiency solutions to increase the capacity of the radio access network as well as support for high data rates. In this context, the 3GPP introduces a new feature in the release 5 specifications denominated high speed downlink packet access (HSDPA). The HSDPA concept appears as an umbrella of features to improve both user and system performance. The concept includes a reduction of the transmission time interval (TTI) to 2 ms, an adaptive modulation and coding (AMC) scheme, and a fast physical layer hybrid ARQ mechanism. In this paper the objective is to analyze the HSDPA performance for streaming, interactive, and background services. Relevant characteristics such as the QoS demands of the different traffic classes, the throughput and delay characteristics has been analyzed and compared with shared channel. We also propose a new packet-scheduling scheme for HSDPA transmission, which improves the overall performance and fairness among the packet users.

The 3G UMTS is currently undergoing inherent changes. The expected release 5&6 of UMTS will contain a new set of features known collectively as high speed downlink packet access (HSDPA). In this paper, we propose two packet scheduling algorithms for HSDPA, shortest queue first (SQF) and longest queue first (LQF), to provide priority scheduling between services of different quality of service (QoS) classes and fairness between users within the same class. Simulation results show that the proposed algorithms meet QoS requirements of different traffic classes, with the SQF algorithm having a better performance compared to the LQF algorithm.

In order to improve support for higher speed data, 3GPP has developed an evolution of UNTS based on WCDMA known as HSDPA(high speed downlink packet access). The target of HSDPA is to provide service for not only voice user but also higher speed data users. For HSDPA, there are two important parameters, which are the rate ratio and the power ratio between higher speed data signal and voice data signal. In this article, we deduced two useful conclusions, which are based on the research of the relationship between the rate ratio and the power ratio. One of the two conclusions is that the transmission power is in positive proportional to data rate when the user numbers of higher speed data is high, which would result in dramatic interference of multi-user. The other is that the same capacity can be achieved by only using half transmission power when there is one higher speed data user over one transmission time interval. Based on the two conclusions, the feasibility of HSDPA is studied. We found that it is impossible for HSDPA to provide simultaneously service for multiple high-speed data users and voice users. A feasible CDMA/TDMA reform scheme is proposed, which can achieve the design goal of WCDMA HSDPA. The reform scheme employs the method of time domain multiplexing(TDM) to realize the transmission of high speed data over a special CDMA channel. The reform scheme can increase dramatically downlink capacity, improve spectral efficiency, and also reduce system cost by employing simple interference eliminator.

In this paper, a comparison study of various UMTS data transmission techniques is performed. An analysis of the system in the presence of geographically non-uniform multi-service traffic profiles is done for three transmission techniques: Frequency Division Duplex (FDD), Time Division Duplex (TDD), and High Speed Downlink Packet Access (HSDPA). Several combinations were selected: FDD, TDD, FDD combined with HSDPA, FDD combined with TDD, and FDD combined with TDD and HSDPA. The TDD mode is the technique with better results, but the introduction of HSDPA is clearly beneficial for data services, as expected. The distribution of the services by the three techniques is the best scenario, namely for some traffic profiles. For example, for a threshold of 128 kbps (for HSDPA services) and 50 % of the power reserved to HSDPA, it is possible to get 1.4 GB of carried traffic.

This paper proposes a novel packet scheduling algorithm for delay constraint traffic on high speed down link packet access (HSDPA) and also a packet scheduler for this algorithm. In this packet scheduling algorithm, we consider both the delay constraint and the throughput for each traffic class while maximizing the system capacity. Considering the delay constraint and the throughput simultaneously, our method can guarantee different quality of service (QoS) for each traffic class. Finally, in order to demonstrate the performance of our proposed algorithm, we compare our algorithm with the proportional fairness (PF) method and round robin (RR) method by system simulations. Numerical results show that system performance can be significantly improved employing our algorithm compared to that with the PF or RR method.

High speed downlink packet access (HSDPA) is a packet-based data service in UMTS networks that supports data rates of several Mbit/s, making it suitable for data applications ranging from file transfer to multimedia streaming. In spite of the fairly high data rates that HSDPA offers, the shared downlink radio channel used in HSDPA is a challenging environment for delay- and loss-sensitive applications. It is relatively easy to partition resources over wired links with known link capacity. Nevertheless, such partitioning is complex for wireless links with variable capacity; due to the dynamic nature of the link, it is difficult to effectively allocate the resources (i.e., time slots) between users who may be paying different prices for different services. In this paper we study the general problem of resource partitioning for shared wireless links like HSDPA. We consider different QoS classes or user groups, and the use of MAC-layer scheduling for resource partitioning between groups and between individual users. We propose a variant of an existing HSDPA scheduler called required activity detection (RAD) scheduler. The proposal is studied using a detailed UMTS/HSDPA simulator.

무선 접속을 통한 인터넷 서비스가 보편화된 최근 사람이 서비스를 이용하는 과정에서 실제로 느끼는 품질인 사용자 체감 품질(QoE; Quality of Experience)의 중요성이 더욱 강조되고 있는데 사용자 체감 품질은 서비스 품질 (QoS; Quality of Service)와 같이 객관적인 수치화가 불가능하다는 특징이 있다. 유선과는 달리 무선 접속을 통해서 제공되는 IP 서비스는 매우 많은 요인에 의해서 사용자 체감 품질이 영향을 받을 수 있다. 따라서 본 논문에서는 대표적인 무선 접속 서비스인 HSPA (High Speed Packet Access)를 통해서 음성 서비스가 제공될 때 측정 가능한 품질지표를 선정하고 이들에 대한 실측값을 통계적으로 분석하여 서비스 품질과 사용자 체감 품질 지표와의 상관관계를 밝히고자 한다. 분석 결과 RSSI (Received Signal Strength Indicator)와 전송 지연의 상관관계가 매우 높고 그에 이어 전송 지연과 MOS (Mean Opinion Score)와 매우 높은 상관관계를 가짐을 알 수 있었다. As internet services are being provided through a wireless access, the importance of quality of experience (QoE) is stressed that is defined as the quality that indicates user's actual feeling when a service is provided. Unlike quality of service (QoS) that can be expressed as a numerical value, it is difficult to represent QoE in an objective way. If an internet service is serviced over a wireless channel, its QoE can be affected by a number of factors such as fading, mobility and so on. This paper, therefore, attempts to specify the relationship between QoE and QoS by conducting practical measurements for the voice service through 3G high speed packet access (HSPA) access network. Analysing the measured results, it has been shown that received signal strength indicator (RSSI) has a great influence on mean opinion score (MOS) through transmission delay.