<p>One goal in the development of future cellular systems is to increase performance. Channel dependent scheduling can possibly contribute to a performance enhancement. It requires channel qualityinformation and uplink channel knowledge is often incomplete. This master thesis work compares channel dependent scheduling and channel independent scheduling for a Single Carrier Frequency Division Multiple Access-based uplink in time domain and time and frequencydomain assuming continuous channel quality information updates. It also evaluates different methods for providing channel quality information by investigating how the limited channel knowledge they supply affects the performance of channel dependent scheduling.</p><p>Single-cell simulations with perfect channel knowledge indicate small gains for channel dependent scheduling. Large gains are seen when performing frequency and time domain scheduling instead of only time domain scheduling. Limited channel knowledge causes performance loss for channel dependent scheduling. The performance is only slightly decreased if a method with sufficiently frequent providing of channel quality information updates is applied.</p><p>More realistic multi-cell simulations show large gains for channel dependent scheduling. It is possible that these results are influenced by link adaptation and scheduling problems due to non predictable interference when performing dynamic scheduling. In the comparison between channel dependent and channel independent scheduling the channel dependent scheduling can benefit from the fact that the selected channel dependent scheduling algorithms result in a more static scheduling than the selected channel independent scheduling algorithms do.</p>

The uplink of code division multiple access (CDMA) cellular radio systems is often interference limited. The interference originates from many users whose transmission powers are not observable for the system. This thesis introduces uplink load and applies means of explicitly considering the users’ radio environment when approximating and controlling the load. A desirable property of all cellular radio systems is uplink feasibility, i.e., existence of finite user transmission powers to support the allocated services. Uplink load can be considered as a measure of how far from infeasibility the system is. The performed characterization of uplink load lead to two concrete definitions related to the amount of received and transmitted power, respectively. An important part of the total load is the intercell load which is caused by users connected to neighboring base stations. If not carefully handled, the intercell load can jeopardize uplink feasibility. Conversely, knowledge of a lower intercell load can be used to increase the resource assignments. A common denominator in all the work in this thesis is that the intercell load is explicitly considered. When approximating uplink load, a centralized approach is adopted to study information gathered in several base stations. This yields good approximations of the average load. However, centralized approximations can not detect momentarily peaks in the load. A number of resource allocation algorithms making control decisions in the local base stations are proposed based on experience from characterizing uplink load. As the algorithms study the intercell load, yet without measuring the interference power, they are robust in the sense that they will never assign resources yielding an infeasible system. A straightforward way of controlling the uplink load is to use measurements of the received interference power. This approach, just as the proposed load approximations, can gain from knowing the background noise power. The same framework used for designing robust resource allocation algorithms, is also used for estimating the background noise power.

The increasing use of data services and the importance of IP basedservices in third generation mobile communication system (3G), requires the transmission from the cell phone to the base station, i.e. uplink, to manage high speed data rates. In the air interface for 3G in Europe, WCDMA, a concept for enhancing the transmission from the cell phone to the base station, called Enhanced Uplink, is being standardized. The overall goal is to provide high speed data access for the uplink. One of the requirements is that the enhanced uplink channels must be able to coexist with already existing WCDMA releases. For example, the enhanced uplink must not impact seriously on real time services, such as speech, carried on current WCDMA channels. The purpose of this work is to study how the quality, coverage and capacity of real time services carried on previous WCDMA releases is affected when introducing the Enhanced Uplink in a WCDMA network. The main focus of the study is thus to demonstrate the trade-off between voice and best effort performances. Theoretical assessments and simulations show that the Enhanced Uplink has many advantages over previous WCDMA releases. For example the Enhanced Uplink yields a larger system throughput for all voice loads. The noise rise, i.e. the ratio of total received power to the background noise power is being considered as the resource. It is shown that user traffic carried on the Enhanced Uplink is able to operate under a higher noise rise level as well as to get a higher throughput per noise rise. The resource is hence more efficiently utilized.

Power control is one of the technologies used to utilize the radio resources as efficient as possible in WCDMA. The transmission power is adjusted to transmit with the lowest power level possible while the required received signal quality is maintained. Since there are large variation in channel quality over time, the power has to be adjusted to compensate for these variations. During moments of bad channel conditions a high transmission power has to be used which will to a greater extent interfere with other users in the system. To solve this problem a concept called transmission timing was proposed. The basic idea is that the transmitter avoids data transmission during the short periods of bad channel conditions caused by fast fading. Higher bit rates can be used to compensate for this when the channel conditions are good. In this thesis the performance of transmission timing applied to uplink data transmissions is evaluated. This is accomplished through a theoretical analysis as well as simulations of a cellular system using transmission timing. Lowered transmission power is achieved and thus lowered interference is induced. Simulations showed that the transmission power can be lowered by up to 1.6 dB compared to ordinary continuous transmission with equal average data rate. These results are however strongly dependent on the used radio environment. It is also showed that transmission timing provides increased system stability in case of rapid changes in the load situation.

One goal in the development of future cellular systems is to increase performance. Channel dependent scheduling can possibly contribute to a performance enhancement. It requires channel qualityinformation and uplink channel knowledge is often incomplete. This master thesis work compares channel dependent scheduling and channel independent scheduling for a Single Carrier Frequency Division Multiple Access-based uplink in time domain and time and frequencydomain assuming continuous channel quality information updates. It also evaluates different methods for providing channel quality information by investigating how the limited channel knowledge they supply affects the performance of channel dependent scheduling. Single-cell simulations with perfect channel knowledge indicate small gains for channel dependent scheduling. Large gains are seen when performing frequency and time domain scheduling instead of only time domain scheduling. Limited channel knowledge causes performance loss for channel dependent scheduling. The performance is only slightly decreased if a method with sufficiently frequent providing of channel quality information updates is applied. More realistic multi-cell simulations show large gains for channel dependent scheduling. It is possible that these results are influenced by link adaptation and scheduling problems due to non predictable interference when performing dynamic scheduling. In the comparison between channel dependent and channel independent scheduling the channel dependent scheduling can benefit from the fact that the selected channel dependent scheduling algorithms result in a more static scheduling than the selected channel independent scheduling algorithms do.

Zugl.: Aachen, Techn. Hochsch., Diss., 2008.

Zugl.: Dresden, Techn. University, Diss., 2008.

MAIA, Adyson Magalhães. Um mercanismo para escalonamento de pacotes no uplink da rede LTE no contexto da comunicação máquina-a-máquina. 2013. 66 f. Dissertação (Mestrado em Ciência da Computação)-Universidade Federal do Ceará, Fortaleza, 2013. / Submitted by Anderson Silva Pereira (anderson.pereiraaa@gmail.com) on 2017-01-10T17:01:54Z No. of bitstreams: 1 2013_dis_ammaia.pdf: 1825299 bytes, checksum: 3f411e2308c0764db18086299cea938c (MD5) / Approved for entry into archive by Rocilda Sales (rocilda@ufc.br) on 2017-01-11T15:37:41Z (GMT) No. of bitstreams: 1 2013_dis_ammaia.pdf: 1825299 bytes, checksum: 3f411e2308c0764db18086299cea938c (MD5) / Made available in DSpace on 2017-01-11T15:37:41Z (GMT). No. of bitstreams: 1 2013_dis_ammaia.pdf: 1825299 bytes, checksum: 3f411e2308c0764db18086299cea938c (MD5) Previous issue date: 2013 / Cellular networks are expected to play an important role in the future of Internet of Things (IoT) and in the Machine-to-Machine (M2M) communication with the LTE network gaining increasing highlights for this purpose. However, improvements in the LTE network are necessary because of the intrinsic characteristics of M2M communication, such as the large number of devices and the diversity of the requirements of their applications, which differen- tiate from the Human-to-Human (H2H) communication for which the network was initially designed. Among these improvements, it includes improving the uplink packet scheduler of LTE standard to dealing the M2M communication and meets your requirements without serious impacts on the H2H communication. This work proposes a mechanism for the uplink packet scheduler in the context of M2M communication that uses current and past information from the network and each device to satisfy their requirements of Quality of Service (QoS), avoid the problem of starvation and control the congestion caused by these devices. The results indicate that the proposal can reduce the impact of the M2M communication over the H2H and ensure justice in resource allocation, however, the level of satisfaction of QoS requirements decreases with increasing of H2H traffic. / As redes celulares são esperadas para desempenhar um importante papel no futuro da Internet das Coisas (Internet of Things - IoT) e na comunicação Máquina-a-Máquina (Machine-to-Machine - M2M), com a rede LTE ganhando cada vez mais destaque tanto da academia quanto da indústria na implantação deste cenário. Contudo, melhorias na rede LTE são necessárias devido às características intrínsecas da comunicação M2M, como a grande quantidade de dispositivos e a diversidade nos requerimentos das suas aplicações, que os diferenciam da comunicação Humano-a-Humano (Human-to-Human - H2H) para a qual a rede foi inicialmente projetada. Dentre essas melhorias, está o aperfeiçoamento no escalonamento de pacotes no uplink definido no padrão para que trate o caso da comunicação M2M e atenda aos seus requerimentos sem causar grandes impactos na comunicação H2H. Este trabalho propõe um mecanismo para o escalonamento de pacotes no uplink da rede LTE no contexto da comunicação M2M que utiliza as informações atuais e passadas da rede e de cada dispositivo para satisfazer os requisitos de Qualidade de Serviço (QoS) dos dispositivos M2M, evitar o problema de inanição e controlar o congestionamento causado por estes dispositivos. Os resultados obtidos indicam que a proposta consegue reduzir o impacto da comunicação M2M sobre a H2H e garantir justiça na alocação de recursos. No entanto, o nível de satisfação dos requisitos de QoS dos dispositivos M2M diminui com o aumento do tráfego H2H.

Increasing number of devices demand for low latency and high-speed data transmission require that the computation resources to be closer to users. The emerging Mobile Edge Computing (MEC) technology aims to bring the advantages of cloud computing which are computation, storage and networking capabilities in close proximity of user. MEC servers are also integrated with cloud servers which give them flexibility of reaching vast computational power whenever needed. In this thesis, leveraging the idea of Mobile Edge Computing, we propose algorithms for cost-efficient and energy-efficient the placement of Mobile Edge nodes. We focus on uplink energy-efficiency which is essential for certain applications including augmented reality and connected vehicles, as well as extending battery life of user equipment that is favorable for all applications. The experimental results show that our proposed schemes significantly reduce the uplink energy of devices and minimizes the number of edge nodes required in the network.

In the 3GPP LTE, different radio resource management (RRM) techniques have been proposed in order to improve the uplink performance. Frequency hopping is one of the techniques that can be used to improve the uplink performance by providing frequency diversity and interference averaging. The hopping can be between subframes (inter-subframe) or within a subframe (intra-subframe). 3GPP specifies two types of frequency hopping for the LTE uplink, hopping based on explicit hopping information in the scheduling grant and sub-band based hopping according to cell-specific hopping and mirroring patterns. In this master’s thesis, theoretical discussion on the frequency hopping schemes is carried out followed by dynamic simulations in order to evaluate the performance gain of frequency hopping. Based on the theoretical analysis, the second type of hopping is selected for detailed study. As a baseline for comparison, dynamic frequency domain scheduling with random frequency resource allocation has been used. Single cell and multi-cell scenarios have been simulated with VoIP traffic model using user satisfaction as a performance metric. The simulation results show that frequency hopping improves the uplink performance by providing frequency diversity in the single cell scenario and both frequency diversity and interference averaging in the multi-cell scenario. The gains in using the hopping schemes were reflected as VoIP capacity (the number of satisfied users) improvement. In this study, the performance of the selected hopping schemes under different hopping parameters is also evaluated. / ttma07@student.bth.se tariku.temesgen.mehari@ericsson.com