A Framework for Enhancing the Energy Efficiency of IoT Devices in 5G Network

A wide range of services, such as improved mobile broadband, extensive machine-type communication, ultra-reliability, and low latency, are anticipated to be delivered via the 5G network. The 5G network has developed as a multi-layer network that uses numerous technological advancements to provide a wide array of wireless services to fulfil such a diversified set of requirements. Several technologies, including software-defined networking, network function virtualization, edge computing, cloud computing, and tiny cells, are being integrated into the 5G networks to meet the needs of various requirements. Due to the higher power consumption that will arise from such a complicated network design, energy efficiency becomes crucial. The network machine learning technique has attracted a lot of interest from the scientific community because it has the potential to play a crucial role in helping to achieve energy efficiency. Utilization factor, access latency, arrival rate, and other metrics are used to study the proposed scheme. It is determined that our system outperforms the present scheme after comparing the suggested scheme to these parameters

Adaptive Communications for Next Generation Broadband Wireless Access Systems

Un dels aspectes claus en el disseny i gestió de les xarxes sense fils d'accés de banda ampla és l'ús eficient dels recursos radio. Des del punt de vista de l'operador, l'ample de banda és un bé escàs i preuat que s´ha d'explotar i gestionar de la forma més eficient possible tot garantint la qualitat del servei que es vol proporcionar. Per altra banda, des del punt de vista del usuari, la qualitat del servei ofert ha de ser comparable al de les xarxes fixes, requerint així un baix retard i una baixa pèrdua de paquets per cadascun dels fluxos de dades entre la xarxa i l'usuari. Durant els darrers anys s´han desenvolupat nombroses tècniques i algoritmes amb l'objectiu d'incrementar l'eficiència espectral. Entre aquestes tècniques destaca l'ús de múltiples antenes al transmissor i al receptor amb l'objectiu de transmetre diferents fluxos de dades simultaneament sense necessitat d'augmentar l'ample de banda. Per altra banda, la optimizació conjunta de la capa d'accés al medi i la capa física (fent ús de l'estat del canal per tal de gestionar de manera optima els recursos) també permet incrementar sensiblement l'eficiència espectral del sistema.L'objectiu d'aquesta tesi és l'estudi i desenvolupament de noves tècniques d'adaptació de l'enllaç i gestió dels recursos ràdio aplicades sobre sistemes d'accés ràdio de propera generació (Beyond 3G). Els estudis realitzats parteixen de la premissa que el transmisor coneix (parcialment) l'estat del canal i que la transmissió es realitza fent servir un esquema multiportadora amb múltiples antenes al transmisor i al receptor. En aquesta tesi es presenten dues línies d'investigació, la primera per casos d'una sola antenna a cada banda de l'enllaç, i la segona en cas de múltiples antenes. En el cas d'una sola antena al transmissor i al receptor, un nou esquema d'assignació de recursos ràdio i priorització dels paquets (scheduling) és proposat i analitzat integrant totes dues funcions sobre una mateixa entitat (cross-layer). L'esquema proposat té com a principal característica la seva baixa complexitat i que permet operar amb transmissions multimedia. Alhora, posteriors millores realitzades per l'autor sobre l'esquema proposat han permès també reduir els requeriments de senyalització i combinar de forma óptima usuaris d'alta i baixa mobilitat sobre el mateix accés ràdio, millorant encara més l'eficiència espectral del sistema. En cas d'enllaços amb múltiples antenes es proposa un nou esquema que combina la selecció del conjunt optim d'antenes transmissores amb la selecció de la codificació espai- (frequència-) temps. Finalment es donen una sèrie de recomanacions per tal de combinar totes dues línies d'investigació, així con un estat de l'art de les tècniques proposades per altres autors que combinen en part la gestió dels recursos ràdio i els esquemes de transmissió amb múltiples antenes.Uno de los aspectos claves en el diseño y gestión de las redes inalámbricas de banda ancha es el uso eficiente de los recursos radio. Desde el punto de vista del operador, el ancho de banda es un bien escaso y valioso que se debe explotar y gestionar de la forma más eficiente posible sin afectar a la calidad del servicio ofrecido. Por otro lado, desde el punto de vista del usuario, la calidad del servicio ha de ser comparable al ofrecido por las redes fijas, requiriendo así un bajo retardo y una baja tasa de perdida de paquetes para cada uno de los flujos de datos entre la red y el usuario. Durante los últimos años el número de técnicas y algoritmos que tratan de incrementar la eficiencia espectral en dichas redes es bastante amplio. Entre estas técnicas destaca el uso de múltiples antenas en el transmisor y en el receptor con el objetivo de poder transmitir simultáneamente diferentes flujos de datos sin necesidad de incrementar el ancho de banda. Por otro lado, la optimización conjunta de la capa de acceso al medio y la capa física (utilizando información de estado del canal para gestionar de manera óptima los recursos) también permite incrementar sensiblemente la eficiencia espectral del sistema.El objetivo de esta tesis es el estudio y desarrollo de nuevas técnicas de adaptación del enlace y la gestión de los recursos radio, y su posterior aplicación sobre los sistemas de acceso radio de próxima generación (Beyond 3G). Los estudios realizados parten de la premisa de que el transmisor conoce (parcialmente) el estado del canal a la vez que se considera que la transmisión se realiza sobre un sistema de transmisión multiportadora con múltiple antenas en el transmisor y el receptor. La tesis se centra sobre dos líneas de investigación, la primera para casos de una única antena en cada lado del enlace, y la segunda en caso de múltiples antenas en cada lado. Para el caso de una única antena en el transmisor y en el receptor, se ha desarrollado un nuevo esquema de asignación de los recursos radio así como de priorización de los paquetes de datos (scheduling) integrando ambas funciones sobre una misma entidad (cross-layer). El esquema propuesto tiene como principal característica su bajo coste computacional a la vez que se puede aplicar en caso de transmisiones multimedia. Posteriores mejoras realizadas por el autor sobre el esquema propuesto han permitido también reducir los requisitos de señalización así como combinar de forma óptima usuarios de alta y baja movilidad. Por otro lado, en caso de enlaces con múltiples antenas en transmisión y recepción, se presenta un nuevo esquema de adaptación en el cual se combina la selección de la(s) antena(s) transmisora(s) con la selección del esquema de codificación espacio-(frecuencia-) tiempo. Para finalizar, se dan una serie de recomendaciones con el objetivo de combinar ambas líneas de investigación, así como un estado del arte de las técnicas propuestas por otros autores que combinan en parte la gestión de los recursos radio y los esquemas de transmisión con múltiples antenas.In Broadband Wireless Access systems the efficient use of the resources is crucial from many points of views. From the operator point of view, the bandwidth is a scarce, valuable, and expensive resource which must be exploited in an efficient manner while the Quality of Service (QoS) provided to the users is guaranteed. On the other hand, a tight delay and link quality constraints are imposed on each data flow hence the user experiences the same quality as in fixed networks. During the last few years many techniques have been developed in order to increase the spectral efficiency and the throughput. Among them, the use of multiple antennas at the transmitter and the receiver (exploiting spatial multiplexing) with the joint optimization of the medium access control layer and the physical layer parameters.In this Ph.D. thesis, different adaptive techniques for B3G multicarrier wireless systems are developed and proposed focusing on the SS-MC-MA and the OFDM(A) (IEEE 802.16a/e/m standards) communication schemes. The research lines emphasize into the adaptation of the transmission having (Partial) knowledge of the Channel State Information for both; single antenna and multiple antenna links. For single antenna links, the implementation of a joint resource allocation and scheduling strategy by including adaptive modulation and coding is investigated. A low complexity resource allocation and scheduling algorithm is proposed with the objective to cope with real- and/or non-real- time requirements and constraints. A special attention is also devoted in reducing the required signalling. However, for multiple antenna links, the performance of a proposed adaptive transmit antenna selection scheme jointly with space-time block coding selection is investigated and compared with conventional structures. In this research line, mainly two optimizations criteria are proposed for spatial link adaptation, one based on the minimum error rate for fixed throughput, and the second focused on the maximisation of the rate for fixed error rate. Finally, some indications are given on how to include the spatial adaptation into the investigated and proposed resource allocation and scheduling process developed for single antenna transmission

An algorithm for multi-objective assignment problem.

Tse Hok Man.Thesis (M.Phil.)--Chinese University of Hong Kong, 2005.Includes bibliographical references (leaves 68-69).Abstracts in English and Chinese.Abstract --- p.iAcknowledgement --- p.iiiChapter 1 --- Introduction --- p.1Chapter 2 --- Background Study --- p.4Chapter 2.1 --- Channel Assignment in Multicarrier CDMA Systems --- p.4Chapter 2.1.1 --- Channel Throughput --- p.5Chapter 2.1.2 --- Greedy Approach to Channel Assignment --- p.6Chapter 2.2 --- Generalised Assignment Problem --- p.7Chapter 2.2.1 --- Branch and Bound Approach for GAP --- p.8Chapter 2.2.2 --- Genetic Algorithm for GAP --- p.10Chapter 2.3 --- Negative Cycle Detection --- p.11Chapter 2.3.1 --- Labeling Method --- p.11Chapter 2.3.2 --- Bellman-Ford-Moore algorithm --- p.13Chapter 2.3.3 --- Amortized Search --- p.14Chapter 3 --- Multi-objective Assignment Problem --- p.15Chapter 3.1 --- Multi-objective Assignment Problem --- p.16Chapter 3.2 --- NP-Hardness --- p.18Chapter 3.3 --- Transformation of the Multi-objective Assignment Problem --- p.19Chapter 3.4 --- Algorithm --- p.23Chapter 3.5 --- Example --- p.25Chapter 3.6 --- A Special Case - Linear Objective Function --- p.32Chapter 3.7 --- Performance on the assignment problem --- p.33Chapter 4 --- Goal Programming Model for Channel Assignment Problem --- p.35Chapter 4.1 --- Motivation --- p.35Chapter 4.2 --- System Model --- p.36Chapter 4.3 --- Goal Programming Model for Channel Assignment Problem --- p.38Chapter 4.4 --- Simulation --- p.39Chapter 4.4.1 --- Throughput Optimization --- p.40Chapter 4.4.2 --- Best-First-Assign Algorithm --- p.41Chapter 4.4.3 --- Channel Swapping Algorithm --- p.41Chapter 4.4.4 --- Lower Bound --- p.43Chapter 4.4.5 --- Result --- p.43Chapter 4.5 --- Future Works --- p.50Chapter 5 --- Extended Application on the General Problem --- p.51Chapter 5.1 --- Latency Minimization --- p.52Chapter 5.2 --- Generalised Assignment Problem --- p.53Chapter 5.3 --- Quadratic Assignment Problem --- p.60Chapter 6 --- Conclusion --- p.65Bibliography --- p.6

Goal programming approach for channel assignment formulation and schemes.

Ng Cho Yiu.Thesis (M.Phil.)--Chinese University of Hong Kong, 2005.Includes bibliographical references (leaves 70-74).Abstracts in English and Chinese.Abstract --- p.iAcknowledgement --- p.iiiPreface --- p.xChapter 1 --- Introduction --- p.1Chapter 1.1 --- Multiple Access --- p.1Chapter 1.1.1 --- Time Division Multiple Access --- p.2Chapter 1.1.2 --- Frequency Division Multiple Access --- p.3Chapter 1.1.3 --- Code Division Multiple Access --- p.3Chapter 1.1.4 --- Hybrid Multiple Access Scheme --- p.4Chapter 1.2 --- Goal Programming --- p.5Chapter 2 --- Previous Works in Channel Assignment --- p.10Chapter 2.1 --- Voice Service Network --- p.10Chapter 2.2 --- Data Network --- p.11Chapter 2.2.1 --- Throughput Optimization --- p.13Chapter 2.2.2 --- Channel Assignment Schemes with QoS Consideration --- p.14Chapter 3 --- General Channel Assignment Scheme --- p.16Chapter 3.1 --- Baseline Model --- p.17Chapter 3.2 --- Goal Ranking --- p.22Chapter 3.3 --- Model Transformation --- p.22Chapter 3.4 --- Proposed Algorithms --- p.23Chapter 3.4.1 --- Channel Swapping Algorithm --- p.24Chapter 3.4.2 --- Best-First-Assign Algorithm --- p.26Chapter 4 --- Special Case Algorithms --- p.28Chapter 4.1 --- Single Order of Selection Diversity --- p.28Chapter 4.1.1 --- System Model --- p.29Chapter 4.1.2 --- Proposed Algorithm --- p.30Chapter 4.1.3 --- Extension of Algorithm --- p.31Chapter 4.2 --- Single Channel Assignment --- p.32Chapter 4.2.1 --- System Model --- p.33Chapter 4.2.2 --- Proposed Algorithms --- p.34Chapter 5 --- Performance Evaluation --- p.37Chapter 5.1 --- General Channel Assignment and Single Channel Assignment --- p.37Chapter 5.1.1 --- System Model --- p.38Chapter 5.1.2 --- Lower Bound of Weighted Sum of Unsatisfactory Function --- p.40Chapter 5.1.3 --- Performance Evaluation I --- p.41Chapter 5.1.4 --- Discussion --- p.44Chapter 5.1.5 --- Performance Evaluation II --- p.44Chapter 5.2 --- Single Order of Selection Diversity Algorithm --- p.47Chapter 5.2.1 --- System Model --- p.47Chapter 5.2.2 --- Performance Evaluation I --- p.49Chapter 5.2.3 --- Performance Evaluation II --- p.53Chapter 6 --- Conclusion and Future Works --- p.58Chapter 6.1 --- Conclusion --- p.58Chapter 6.2 --- Future Works --- p.60Chapter 6.2.1 --- Multi-cell Channel Assignment --- p.60Chapter 6.2.2 --- Theoretical Studies --- p.62Chapter 6.2.3 --- Adaptive Algorithms --- p.62Chapter 6.2.4 --- Assignment of Non-orthogonal Channels --- p.63Chapter A --- Proof of Proposition 3.1 --- p.64Chapter B --- Proof of Proposition 4.1 --- p.66Chapter C --- Assignment Problem --- p.68Bibliography --- p.7

Transmission optimization schemes for multicarrier CDMA systems.

Hu Fan.Thesis (M.Phil.)--Chinese University of Hong Kong, 2005.Includes bibliographical references (leaves 77-81).Abstracts in English and Chinese.Acknowledgement --- p.iAbstract --- p.iiChapter 1 --- Introduction --- p.1Chapter 1.1 --- Evolution of Mobile Communications --- p.1Chapter 1.2 --- Overview of Multicarrier Systems --- p.3Chapter 1.3 --- Outline of This Thesis --- p.5Chapter 2 --- Multicarrier Communication Systems --- p.7Chapter 2.1 --- Introduction --- p.7Chapter 2.2 --- Multicarrier Modulation (MCM) Scheme versus Single Carrier Modulation (SCM) Scheme --- p.8Chapter 2.3 --- Orthogonal Frequency Division Multiplexing (OFDM) Systems --- p.12Chapter 2.4 --- Multicarrier CDMA --- p.16Chapter 2.4.1 --- MC-CDMA --- p.17Chapter 2.4.2 --- MC-DS-CDMA --- p.18Chapter 2.4.3 --- MT-CDMA --- p.19Chapter 3 --- Optimization for MC-CDMA Systems --- p.22Chapter 3.1 --- System Model --- p.22Chapter 3.2 --- Optimization with Normalized Power --- p.27Chapter 3.2.1 --- Transmission Time Minimization --- p.27Chapter 3.2.2 --- Throughput Maximization --- p.32Chapter 3.2.3 --- Performance --- p.33Chapter 3.3 --- Mathematical Programming --- p.36Chapter 3.3.1 --- Nonlinear Programming --- p.37Chapter 3.3.2 --- Convex Programming --- p.39Chapter 3.4 --- Optimization with Power Allocation --- p.42Chapter 3.4.1 --- Transmission Time Minimization with Power Allocation --- p.42Chapter 3.4.2 --- Throughput Maximization with Power Allocation --- p.43Chapter 3.4.3 --- Power Minimization --- p.44Chapter 3.5 --- Long-range Optimization --- p.45Chapter 3.5.1 --- Long-range Transmission Time Minimization --- p.46Chapter 3.5.2 --- Long-range Throughput Maximization --- p.50Chapter 3.5.3 --- Long-range Power Minimization --- p.51Chapter 3.5.4 --- Performance --- p.53Chapter 4 --- Joint Scheduling and Resource Allocation --- p.58Chapter 4.1 --- Queueing Model --- p.58Chapter 4.2 --- Problem Formulation --- p.62Chapter 4.3 --- Suboptimal Algorithm --- p.64Chapter 4.4 --- Performance --- p.69Chapter A --- Convexity Proof of Problem (3.32) --- p.73Chapter B --- Convexity Proof of Problem (3.36) --- p.75Bibliography --- p.7

Técnicas de equalização e pré-codificação para sistemas MC-CDMA

Mestrado em Engenharia Eletrónica e TelecomunicaçõesO número de dispositivos com ligações e aplicações sem fios está a aumentar exponencialmente, causando problemas de interferência e diminuindo a capacidade do sistema. Isto desencadeou uma procura por uma eficiência espectral superior e, consequentemente, tornou-se necessário desenvolver novas arquitecturas celulares que suportem estas novas exigências. Coordenação ou cooperação multicelular é uma arquitectura promissora para sistemas celulares sem fios. Esta ajuda a mitigar a interferência entre células, melhorando a equidade e a capacidade do sistema. É, portanto, uma arquitectura já em estudo ao abrigo da tecnologia LTE-Advanced sob o conceito de coordenação multiponto (CoMP). Nesta dissertação, considerámos um sistema coordenado MC-CDMA com pré-codificação e equalização iterativas. Uma das técnicas mais eficientes de pré-codificação é o alinhamento de interferências (IA). Este é um conceito relativamente novo que permite aumentar a capacidade do sistema em canais de elevada interferência. Sabe-se que, para os sistemas MC-CDMA, os equalizadores lineares convencionais não são os mais eficientes, devido à interferência residual entre portadoras (ICI). No entanto, a equalização iterativa no domínio da frequência (FDE) foi identificada como sendo uma das técnicas mais eficientes para lidar com ICI e explorar a diversidade oferecida pelos sistemas MIMO MC-CDMA. Esta técnica é baseada no conceito Iterative Block Decision Feedback Equalization (IB-DFE). Nesta dissertação, é proposto um sistema MC-CDMA que une a pré-codificação iterativa do alinhamento de interferências no transmissor ao equalizador baseado no IB-DFE, com cancelamento sucessivo de interferências (SIC) no receptor. Este é construído por dois blocos: um filtro linear, que mitiga a interferência inter-utilizador, seguido por um bloco iterativo no domínio da frequência, que separa eficientemente os fluxos de dados espaciais na presença de interferência residual inter-utilizador alinhada. Este esquema permite atingir o número máximo de graus de liberdade e permite simultaneamente um ganho óptimo de diversidade espacial. O desempenho deste esquema está perto do filtro adaptado- Matched Filter Bound (MFB).The number of devices with wireless connections and applications is increasing exponentially, causing interference problems and reducing the system’s capacity gain. This initiated a search for a higher spectral efficiency and therefore it became necessary to develop new cellular architectures that support these new requirements. Multicell cooperation or coordination is a promising architecture for cellular wireless systems to mitigate intercell interference, improving system fairness and increasing capacity, and thus is already under study in LTE-Advanced under the coordinated multipoint (CoMP) concept. In this thesis, efficient iterative precoding and equalization is considered for coordinated MC-CDMA based systems. One of the most efficient precoding techniques is interference alignment (IA), which is a relatively new concept that allows high capacity gains in interfering channels. It is well known that for MC-CDMA systems standard linear equalizers are not the most efficient due to residual inter carrier interference (ICI). However, iterative frequency-domain equalization (FDE) has been identified as one of the most efficient technique to deal with ICI and exploit the inherent space-frequency diversity of the MIMO MC-CDMA systems, namely the one based on Iterative Block Decision Feedback Equalization (IB-DFE) concept. In this thesis, it is proposed a MC-CDMA system that joins iterative IA precoding at the transmitter with IB-DFE successive interference cancellation (SIC) based receiver structure. The receiver is implemented in two steps: a linear filter, which mitigates the inter-user aligned interference, followed by an iterative frequency-domain receiver, which efficiently separates the spatial streams in the presence of residual inter-user aligned interference. This scheme provides the maximum degrees of freedom (DoF) and allows almost the optimum space-diversity gain. The scheme performance is close to the matched filter bound (MFB)

A Review of MAC Scheduling Algorithms in LTE System

The recent wireless communication networks rely on the new technology named Long Term Evolution (LTE) to offer high data rate real-time (RT) traffic with better Quality of Service (QoS) for the increasing demand of customer requirement. LTE provide low latency for real-time services with high throughput, with the help of two-level packet retransmission. Hybrid Automatic Repeat Request (HARQ) retransmission at the Medium Access Control (MAC) layer of LTE networks achieves error-free data transmission. The performance of the LTE networks mainly depends on how effectively this HARQ adopted in the latest communication standard, Universal Mobile Telecommunication System (UMTS). The major challenge in LTE is to balance QoS and fairness among the users. Hence, it is very essential to design a down link scheduling scheme to get the expected service quality to the customers and to utilize the system resources efficiently. This paper provides a comprehensive literature review of LTE MAC layer and six types of QoS/Channel-aware downlink scheduling algorithms designed for this purpose. The contributions of this paper are to identify the gap of knowledge in the downlink scheduling procedure and to point out the future research direction. Based on the comparative study of algorithms taken for the review, this paper is concluded that the EXP Rule scheduler is most suited for LTE networks due to its characteristics of less Packet Loss Ratio (PLR), less Packet Delay (PD), high throughput, fairness and spectral efficiency