An Energy Efficient Semi-static Power Control and Link Adaptation Scheme in UMTS HSDPA

High speed downlink packet access (HSDPA) has been successfully applied in commercial systems and improves user experience significantly. However, it incurs substantial energy consumption. In this paper, we address this issue by proposing a novel energy efficient semi-static power control and link adaptation scheme in HSDPA. Through estimating the EE under different modulation and coding schemes (MCSs) and corresponding transmit power, the proposed scheme can determine the most energy efficient MCS level and transmit power at the Node B. And then the Node B configure the optimal MCS level and transmit power. In order to decrease the signaling overhead caused by the configuration, a dual trigger mechanism is employed. After that, we extend the proposed scheme to the multiple input multiple output (MIMO) scenarios. Simulation results confirm the significant EE improvement of our proposed scheme. Finally, we give a discussion on the potential EE gain and challenge of the energy efficient mode switching between single input multiple output (SIMO) and MIMO configuration in HSDPA.Comment: 9 pages, 11 figures, accepted in EURASIP Journal on Wireless Communications and Networking, special issue on Green Radi

Modelling Load Balancing and Carrier Aggregation in Mobile Networks

In this paper, we study the performance of multicarrier mobile networks. Specifically, we analyze the flow-level performance of two inter-carrier load balancing schemes and the gain engendered by Carrier Aggregation (CA). CA is one of the most important features of HSPA+ and LTE-A networks; it allows devices to be served simultaneously by several carriers. We propose two load balancing schemes, namely Join the Fastest Queue (JFQ) and Volume Balancing (VB), that allow the traffic of CA and non-CA users to be distributed over the aggregated carriers. We then evaluate the performance of these schemes by means of analytical modeling. We show that the proposed schemes achieve quasi-ideal load balancing. We also investigate the impact of mixing traffic of CA and non-CA users in the same cell and show that performance is practically insensitive to the traffic mix.Comment: 8 pages, 6 figures, submitted to WiOpt201

ANALISIS DAN SIMULASI KAPASITAS DEDICATED CHANNEL SISTEM WCDMA DENGAN HSDPA

ABSTRAKSI: Untuk mengikuti perkembangan atas permintaan aplikasi mobile masa depan, 3GPP mempunyai target untuk meningkatkan rata-rata paket data downlink dalam berbagai tingkatan. Sebagai hasilnya, spesifikasi WCDMA telah disusun dengan fitur HSDPA release 5. Sasaran dari HSDPA adalah meningkatkan kapasitas sistem dengan meningkatkan data rate dan mengurangi delay. Peningkatan kapasitas sistem bisa didapat dengan sharing untuk resource code secara dinamis dan power yang ditentukan. Dalam skenario implementasi teknologi HSDPA, ada kemungkinan beberapa sel telah mengimplementasi HSDPA dan sebagiannya belum diterapkan. Apa yang akan terjadi pada sel-sel yang belum menerapkan HSDPA? Ketika HSDPA diimplementasikan pada suatu sel, base station akan menyerap power lebih, sehingga memberikan efek interferensi pada sel-sel yang bersebelahan, yang akhirnya mempengaruhi kapasitas dedicated channel. Untuk power yang lebih tinngi, jika ketersediaan data dalam kanal HSDPA bervariasi, maka efek interferensi pada sel yang bersebelahan akan membesar dan berfluktuasi, sehingga mempengaruhi kapasitas dedicated channel sel-sel tersebut. Penurunan kapasitas dedicated channel akan menonjol jika trafik data HSDPA lebih besar. Data dalam kanal HSDPA yang berfluktuasi tidak menurunkan kapasitas lebih jauh. Hanyalah penerapan power yang lebih yang akan kapasitas dedicated channel. Dalam beberapa kasus, variasinya bisa diabaikan. Dengan perhitungan memakai formula-formula fading rate, power control, interferensi, besarnya SIR, kita bisa mendapatkan besarnya fluktuasi kapasitas sistem dan kualitasnya, serta membandingkannya dengan besaran-besaran referensi. Dari hasil perhitungan didapatkan besar power HSDPA sebesar 12,56 Watt dan dari hasil perhitungan memakai formula interferensi didapatkan nilai SIR sebesar -9,158 dB.Kata Kunci : WCDMA, HSDPA release 5, dedicated channel, base station, resource code, downlink.ABSTRACT: Keeping an eye on the future upcoming demands for mobile applications, 3GPP has the target to enhance the downlink packet data rate in many folds. As a result, WCDMA specifcations have been evolved with the addition of a new feature called HSDPA (High Speed Downlink Packet Access) in Release 5. The goal of HSDPA has been to increase the system capacity by increasing the data rate and reduce the round trip delay. The increase of system capacity has been achieved by dynamic sharing of code resource and certain amount of power. However, in a real deployment scenario, it may happen that some of the cells are implemented with HSDPA and some are not yet; what will happen to the capacity of those cells without HSDPA? When HSDPA is implemented in a cell, the base station uses more power, imparting more interference to the neighbouring cells, thus affecting their dedicated channel capacity. In addition to the higher power, if the availability of data in the HSDPA channel varies, then the interference to the neighbouring cell might be larger and fluctuating, in turn, the dedicated channel capacity of the neighbouring cells might be affected. It has been found that the decrease in the dedicated channel capacity is more if the HSDPA data traffc is larger. The fluctuating data in HSDPA channel has not degraded the capacity further; it is only the higher power, which has affected the dedicated channel capacity. However, in all these cases, variation can be considered as negligible. We can use various formulas such as fading rate, power control, interference system and SIR, we can calculate some fluctuations in system capacity and quality, then we can compare it with reference system. From calculation method, it is gained that HSDPA power for system model is 12,56 Watt and with using interference formula, the SIR calculation result is -9,158 dB.Keyword: High Speed Downlink Packet Access (HSDPA), 3rd Generation Partnership Project (3GPP)

TD-SCDMA Relay Networks

PhDWhen this research was started, TD-SCDMA (Time Division Synchronous Code Division Multiple Access) was still in the research/ development phase, but now, at the time of writing this thesis, it is in commercial use in 10 large cities in China including Beijing and Shang Hai. In all of these cities HSDPA is enabled. The roll-out of the commercial deployment is progressing fast with installations in another 28 cities being underway now. However, during the pre-commercial TD-SCDM trail in China, which started from year 2006, some interference problems have been noticed especially in the network planning and initialization phases. Interference is always an issue in any network and the goal of the work reported in this thesis is to improve network coverage and capacity in the presence of interference. Based on an analysis of TD-SCDMA issues and how network interference arises, this thesis proposes two enhancements to the network in addition to the standard N-frequency technique. These are (i) the introduction of the concentric circle cell concept and (ii) the addition of a relay network that makes use of other users at the cell boundary. This overall approach not only optimizes the resilience to interference but increases the network coverage without adding more Node Bs. Based on the cell planning parameters from the research, TD-SCDMA HSDPA services in dense urban area and non-HSDPA services in rural areas were simulated to investigate the network performance impact after introducing the relay network into a TD-SCDMA network. The results for HSDPA applications show significant improvement in the TDSCDMA relay network both for network capacity and network interference aspects compared to standard TD-SCDMA networks. The results for non- HSDPA service show that although the network capacity has not changed after adding in the relay network (due to the code limitation in TD-SCDMA), the TD-SCDMA relay network has better interference performance and greater coverage

Mobility: a double-edged sword for HSPA networks

This paper presents an empirical study on the performance of mobile High Speed Packet Access (HSPA, a 3.5G cellular standard) networks in Hong Kong via extensive field tests. Our study, from the viewpoint of end users, covers virtually all possible mobile scenarios in urban areas, including subways, trains, off-shore ferries and city buses. We have confirmed that mobility has largely negative impacts on the performance of HSPA networks, as fast-changing wireless environment causes serious service deterioration or even interruption. Meanwhile our field experiment results have shown unexpected new findings and thereby exposed new features of the mobile HSPA networks, which contradict commonly held views. We surprisingly find out that mobility can improve fairness of bandwidth sharing among users and traffic flows. Also the triggering and final results of handoffs in mobile HSPA networks are unpredictable and often inappropriate, thus calling for fast reacting fallover mechanisms. We have conducted in-depth research to furnish detailed analysis and explanations to what we have observed. We conclude that mobility is a double-edged sword for HSPA networks. To the best of our knowledge, this is the first public report on a large scale empirical study on the performance of commercial mobile HSPA networks

Usage of link-level performance indicators for HSDPA network-level simulations in E-UMTS

The paper describes integration of HSDPA (high-speed downlink packet access) link-level simulation results into network-level simulations for enhanced UMTS. The link-level simulations model all physical layer features depicted in the 3GPP standards. These include: generation of transport blocks; turbo coding; rate matching; spreading; scrambling; modulation. At the receiver side, all complementary blocks are designed, with soft-decision demodulation, and a turbo decoder using the MAP (maximum a posteriori) algorithm with 8 iterations. An analytical formula is defined that fits the CQI (channel quality indicator) dependent BLER (block error rate) versus E/sub b//N/sub 0/ results in an AWGN channel. This formula models the physical layer in the network-level simulator. A further extension for frequency selective fading channels has been defined. The network-level simulator includes propagation models that provide SNR values. Based on these SNR values and the simplified physical layer model, an algorithm selects the CQI, and determines the actual BLER at time of reception. The rounding down and delaying of the CQI reporting, which corresponds to the W-CDMA standard, has a significant impact on throughput and transfer delay of the HS-DSCH. Some compensation can be found in a modified transmission. The integration of the link-level and network-level simulators gives accurate and realistic results that can be used in more studies that focus on network layer aspects of packet based services over HSDP

Final report on the evaluation of RRM/CRRM algorithms

Deliverable public del projecte EVERESTThis deliverable provides a definition and a complete evaluation of the RRM/CRRM algorithms selected in D11 and D15, and evolved and refined on an iterative process. The evaluation will be carried out by means of simulations using the simulators provided at D07, and D14.Preprin