The methods for efficient safety message dissemination in VANETs were proposed. First, the method for using multi-channel was proposed. Using the proposed multi-channel method (divide-and-deliver algorithm), the safety message was delivered to the target device with less delay compared to the traditional single-channel method. This method showed resilient performance even in poor wireless channels compared to the single-channel method. Second, to improve low reliability in low vehicle density situations, the enhanced divide-and-deliver algorithm was proposed. The network coding was a key technique to the enhancement. For the efficient use of network coding, rigorous analysis was conducted and an algorithm was proposed to change the number of network coding packets adaptively by the vehicle densities. Finally, the method for delivering safety messages to multi-direction was proposed. This multi-vehicle selection broadcast (MSB) algorithm avoided the collision between multiple rebroadcasts among vehicles and removed unnecessary packets by using backoff slots. The contributions of this research include reducing delay and increasing reliability for the dissemination of safety messages.

With the achievement of autonomous flight for small unmanned aircraft, currently ongoing research is expanding the capabilities of systems utilizing such vehicles for various tasks. This allows shifting the research focus from the individual systems to task execution benefits resulting from interaction and collaboration of several aircraft. Given that some available high-fidelity simulations do not yet support multi-vehicle scenarios, the presented work introduces a framework which allows several individual single-vehicle simulations to be combined into a larger multi-vehicle scenario with little to no special requirements towards the single-vehicle systems. The created multi-vehicle system offers real-time software-in-the-loop simulations of swarms of vehicles across multiple hosts and enables a single operator to command and control a swarm of unmanned aircraft beyond line-of-sight in geometrically correct two-dimensional cluttered environments through a multi-hop network of data-relaying intermediaries. This dissertation presents the main aspects of the developed system: the underlying software framework and application programming interface, the utilized inter- and intra-system communication architecture, the graphical user interface, and implemented algorithms and operator aid heuristics to support the management and placement of the vehicles. The effectiveness of the aid heuristics is validated through a human subject study which showed that the provided operator support systems significantly improve the operators' performance in a simulated first responder scenario. The presented software is released under the Apache License 2.0 and, where non-open-source parts are used, software packages with free academic licenses have been chosen--resulting in a framework that is completely free for academic research.

No description available.

In recent years, mobile communications have become affordable and popular. High cellular capacity in terms of number of users and data-rates is in need. As the available frequency spectrums for mobile communications are limited, the utilization of the radio resources to achieve high capacity without imposing high equipment cost is of utmost importance. Recently, multi-hop cellular networks (MCNs) were introduced. These networks have the potential of enhancing the cell capacity and extending the cell coverage at low extra cost. However, in a cellular network, the cell or system capacity is inversely related to the cell size. In MCNs, the cell size, the network density and topology affect the coverage of source nodes and the total demands that can be served and, thus, the system throughput. Although the cell size is an important factor, it has not been exploited for maximizing throughput. Another major issue in MCNs is the increase in packet delay because multi-hopping is involved. High packet delay affects quality of service provisioning in these networks. In this thesis, we propose the Optimal Cell Size (OCS) and the Optimal Channel Assignment (OCA) schemes to address the cell size and packet delay issues for a time division duplex (TDD) wideband code division multiple access (W-CDMA) MCN. OCS finds the optimal cell sizes to provide an optimal balance of cell capacity and coverage to maximize the system throughput, whereas OCA assigns channels optimally in order to minimize packet relaying delay. Like many optimized schemes, OCS and OCA are computationally expensive and may not be suitable for large real-time problems. Hence, we also propose heuristics for solving the problems. For the cell size problem, we propose two heuristics: Smallest Cell Size First (SCSF) and Highest Throughput Cell Size First (HTCSF). For the channel assignment problem, we propose the Minimum Slot Waiting First (MSWF) heuristic. Simulation results show that OCS achieves high throughput compared to that of conventional (single-hop) cellular networks and OCA achieves low packet delay in MCNs. Results also show that the heuristics, SCSF, HTCSF and MSWF, provide good results compared to the optimal ones provided by OCS and OCA, respectively. / Thesis (Ph.D, Computing) -- Queen's University, 2009-02-02 22:53:41.825

This thesis analyzes the Bit Error Rate (BER) performance of Orthogonal Frequency Division Multiplexing (OFDM) systems in mobile multi-hop relaying channels. We consider the uplink scenario and quantify the effects of mobile channel impairments such as Doppler Shift due to user mobility per hop, high-power amplifier distortions when amplifying the transmitted/relayed OFDM symbol per hop, as well as the cumulative effects of these impairments over multi-hop relaying channels. It is shown that the resulting inter-carrier interference (ICI) due to the cumulative effects of the phase noise generated by these impairments per hop becomes very significant in a multi-hop relaying communication system, and severely degrades the BER performance of the system. Simulation results agree well with, and validate the analysis. / Thesis (Ph.D, Electrical & Computer Engineering) -- Queen's University, 2011-05-05 15:15:39.576

With the growth of multimedia services, it is essential to find new transmission schemes to support higher data rates in wireless networks. In this thesis, we study networks in which the Channel State Information (CSI) is only available at the destination. We focus on the analysis of three different network setups. For each case, we propose a transmission scheme which maximizes the average performance of the network. The first scenario, which is studied in Chapter 2, is a multi-hop network in which the channel gain of each hop changes quasi-statically from one transmission block to the other. Our main motivation to study this network is the recent advances in deployment of relay nodes in wireless networks (e.g., LTE-A and IEEE 802.16j). In this setup, we assume that all nodes are equipped with a single antenna and the relay nodes are not capable of data buffering over multiple transmission blocks. The proposed transmission scheme is based on infinite-layer coding at all nodes (the source and all relays) in conjunction with the Decode-and-Forward DF relaying. The objective is to maximize the statistical average of the received rate per channel use at the destination. To find the optimal parameters of this code, we first formulate the problem for a two-hop scenario and describe the code design algorithm for this two-hop setting. The optimality of infinite-layer DF coding is also discussed for the case of two-hop networks. The result is then generalized to multi-hop scenarios. To show the superiority of the proposed scheme, we also evaluate the achievable average received rate of infinite-layer DF coding and compare it with the performance of previously known schemes. The second scenario, studied in Chapter 3, is a single-hop network in which both nodes are equipped with multiple antennas, while the channel gain changes quasi-statically and the CSI is not available at the source. The main reason for selecting this network setup is to study the transmission of video signals (compressed using a scalable video coding technique, e.g., SVC H.264/AVC) over a Multiple-Input Multiple-Output (MIMO) link. In this setup, although scalable video coding techniques compress the video signal into layers with different importance (for video reconstruction), the source cannot adapt the number of transmitted layers to the capacity of the channel (since it does not have the CSI in each time slot). An alternative approach is to always transmit all layers of the compressed video signal, but use unequal error protection for different layers. With this motivation, we focus on the design of multilayer codes for a MIMO link in which the destination is only able to perform successive decoding (not joint-decoding). In this chapter, we introduce a design rule for construction of multilayer codes for MIMO systems. We also propose a algorithm that uses this design rule to determine the parameters of the multilayer code. The performance analysis of the proposed scheme is also discussed in this chapter. In the two previous scenarios, the ambiguity of the source regarding the channel state comes from the fact that the channel gains randomly change in each transmission block and there is no feedback to notify the source about the current state of the channel. Apart from these, there are some scenarios in which the channel state is unknown at the source, even though the channel gain is fixed and the source knows its value. The third scenario of this thesis presents an example of such network setups. More precisely, in Chapter 4, we study a multiple access network with K users and one Access Point (AP), where all nodes are equipped with multiple antennas. To access the network, each user independently decides whether to transmit in a time slot or not (no coordination between users). Considering a two-user random access network, we first derive the optimal value of network average Degrees of Freedom (DoF) (introduced in Section 4.1). Generalizing the result to multiuser networks, we propose an upper-bound for the network average DoF of a K-user random access network. This upper-bound is then analyzed for different network configurations to identify the network classes in which the proposed upper-bound is tight. It is also shown that simple single-stream data transmission achieves the upper-bound in most network settings. However, for some network configurations, we need to apply multi-stream data transmission in conjunction with interference alignment to reach the upper-bound. Some illustrative examples are also presented in this chapter.

The combination of infrastructure-to-vehicle and vehicle-to-vehicle communications, namely the multi-hop Vehicular Communications Network (VCN) , appears as a promising solution for the ubiquitous access to IP services in vehicular environments. In this thesis, we address the challenges of multi-hop VCN, and investigate the seamless provision of IP services over such network. Three different schemes are proposed and analyzed. First, we study the limitations of current standards for the provision of IP services, such as 802.11p/WAVE, and propose a framework that enables multi-hop communications and a robust IP mobility mechanism over WAVE. An accurate analytical model is developed to evaluate the throughput performance, and to determine the feasibility of the deployment of IP-based services in 802.11p/WAVE networks. Next, the IP mobility support is extended to asymmetric multi-hop VCN. The proposed IP mobility and routing mechanisms react to the asymmetric links, and also employ geographic location and road traffic information to enable predictive handovers. Moreover, since multi-hop communications suffer from security threats, it ensures that all mobility signalling is authenticated among the participant vehicles. Last, we extend our study to a heterogeneous multi-hop VCN, and propose a hybrid scheme that allows for the on-going IP sessions to be transferred along the heterogeneous communications system. The proposed global IP mobility scheme focuses on urban vehicular scenarios, and enables seamless communications for in-vehicle networks, commuters, and pedestrians. The overall performance of IP applications over multi-hop VCN are improved substantially by the proposed schemes. This is demonstrated by means of analytical evaluations, as well as extensive simulations that are carried out in realistic highway and urban vehicular scenarios. More importantly, we believe that our dissertation provides useful analytical tools, for evaluating the throughput and delay performance of IP applications in multi-hop vehicular environments. In addition, we provide a set of practical and efficient solutions for the seamless support of IP tra c along the heterogeneous and multi-hop vehicular network, which will help on achieving ubiquitous drive-thru Internet, and infotainment traffic access in both urban and highway scenarios.

OLIVEIRA, P. M. R. PARATUCK-N semi-blind receivers for multi-hop cooperative MIMO relay systems. 2017. 51 f. Dissertação (Mestrado em Engenharia de Teleinformática)–Centro de Tecnologia, Universidade Federal do Ceará, Fortaleza, 2017. / Submitted by Renato Vasconcelos (ppgeti@ufc.br) on 2017-09-09T02:17:00Z No. of bitstreams: 1 2017_dis_pmroliveira.pdf: 1188957 bytes, checksum: 745420c86668fea09707dfcc7364adf8 (MD5) / Rejected by Marlene Sousa (mmarlene@ufc.br), reason: Prezado Pedro: Existe uma orientação para que normalizemos as dissertações e teses da UFC, em suas paginas pré-textuais e lista de referencias, pelas regras da ABNT. Por esse motivo, sugerimos consultar o modelo de template, para ajudá-lo nesta tarefa, disponível em: http://www.biblioteca.ufc.br/educacao-de-usuarios/templates/ Vamos agora as correções sempre de acordo com o template: 1. Na capa as informações relativas a hierarquia institucional deve ser em língua portuguesa, Nome da INSTITUIÇÃO; do CENTRO; do DEPARTAMENTO e do PROGRAMA DE PÓS-GRADUAÇÃO. Nesta ordem. Todas as informações devem está em negrito e em caixa alta. Retire a informação Master’s Degree Dissertation e também o nome do estado e o mes. Deixe apenas o nome da cidade e o ano. 2. Na folha de rosto (que segue a capa) Veja o modelo de apresentação das informações de acordo com o template. Apenas o titulo deve ficar em inglês as demais informações são em português. A partir da folha de rosto, todas as outras devem ficar em inglês. Não use negrito nessa folha. Deixe apenas o nome da cidade e o ano. A ficha catalográfica deve vir depois da folha de rosto e as palavras relacionadas aos assuntos devem ser em português. 3. A folha de aprovação naõ deve ter nenhuma informação em negrito. Veja o tamanho da fonte. 4. A dedicatória deve ser depois da folha de aprovação e não é em negrito. 5. A palavra Acknowledgments é em caixa alta, negrito e centralizada na folha. Não use negrito no texto. As folhas prétextuais devem ser contadas mas não são numeradas. Retire numeração. 6. O resumo deve vir antes do Abstract, mesmo quando o trabalho for em língua inglesa. A palavra resumo é em caixa alta, negrito e centralizada na folha. Não use negrito no texto e nem use parágrafos. A palavra abstract é em caixa alta, negrito e centralizada na folha. Não use negrito no texto e nem use parágrafos. 7. As palavras List of Figures, List of Tables, Acronyms, Notation e Sumary são em caixa alta, negrito e centralizada na folha. Não use negrito no texto 8. O sumário está fora dos padrões. Veja uso de maiusculo, minusculo, negrito e itálico nas seções. Não coloque em formato de capítulos e nem coloque as pre-textuais no sumário. Use a palavra referencias e não bibliografia 9. Na lista de referências, Coloque os nomes dos autores entrando pelo sobrenome, seguido do pré nome. Ex. ALMEIDA, A. Se vc optar por abreviar os nomes em toda a lista eles devem ser abreviados. Se vc optar em colocar por extenso em toda e lista deve ficar por extenso para haver uma padronização. Os títulos das publicações devem ser destacadas com o uso do negrito (não use aspas). Com exceção dos artigos de periódicos que devem ser destacados o nome das revistas e não o titulo do artigo. Ao citar os artigos coloque as abreviações v. n. p. e não vol. no e pp. Após essas correções, enviaremos o nada consta por e-mail. Att. Marlene Rocha mmarlene@ufc.br on 2017-09-11T12:55:01Z (GMT) / Submitted by Renato Vasconcelos (ppgeti@ufc.br) on 2017-09-14T13:32:11Z No. of bitstreams: 1 2017_dis_pmroliveira.pdf: 1155061 bytes, checksum: 0da92fa912cabfa49b279fbe8c199877 (MD5) / Rejected by Marlene Sousa (mmarlene@ufc.br), reason: Prezado Pedro e Renato: Será que foi enviada a versão certa? Tenho a impressão que já fiz as recomendações de correção e o Pedro afirma que corrigiu, mas a versão que abri no Repositório ainda esta sem as alterações que solicitei. Marlene on 2017-09-14T16:38:31Z (GMT) / Submitted by Renato Vasconcelos (ppgeti@ufc.br) on 2017-10-03T13:47:30Z No. of bitstreams: 1 2017_dis_pmroliveira.pdf: 1357256 bytes, checksum: 308dc86c85e412f7947531cc8692dd60 (MD5) / Approved for entry into archive by Marlene Sousa (mmarlene@ufc.br) on 2017-11-08T17:23:03Z (GMT) No. of bitstreams: 1 2017_dis_pmroliveira.pdf: 1357256 bytes, checksum: 308dc86c85e412f7947531cc8692dd60 (MD5) / Made available in DSpace on 2017-11-08T17:23:03Z (GMT). No. of bitstreams: 1 2017_dis_pmroliveira.pdf: 1357256 bytes, checksum: 308dc86c85e412f7947531cc8692dd60 (MD5) Previous issue date: 2017-07-28 / Cooperative communication systems is a promising research field nowadays due to its advantages, like the increase of the received power, better quality of signal, and spatial diversity gains. Specifically, multi-hop systems are a very important part of cooperative communications, since they have the advantage of needing less transmission power than the direct systems. Also, multiple-input multiple-output (MIMO) systems are present in several standards of communications, providing some advantages, like the spatial multiplexing gains. Based on this scenario, this work proposes two semi-blind receivers based on the Kronecker product, that jointly estimate the symbol and the channels in a multi-hop Amplify-and-Forward (AF) MIMO relay-assisted system (AF protocol is widely used, due to its great performance and easy implementation). We consider a transmission scheme using a simplified Khatri-Rao space-time (KRST) coding at the source node, combined with an AF scheme at the relay nodes. We show that the third-order tensor of signals received by the destination node satisfies a PARATUCK-(K+1) decomposition, where K is the number of relays. This tensorial modeling enables a semi-blind estimation of symbols and channels with the use of a few pilot symbols. The first receiver called Least-Squares Kronecker-Factorization (LS-KF) is based on a factorization of the Kronecker product matrix between the symbols and the channel matrices. The other receiver called Least-Squares Kronecker-Rearrangement (LS-KR) is based on a rearrangement of this Kronecker product matrix, in order to achieve a rank-1 matrix. The performance of these receivers is evaluated by means of computational simulation results proving their efficiency in estimating the channels and, hence, providing a low Symbol Error Rate (SER). The proposed algorithms in the multi-hop scenario were compared to each other and with the two-hop and three-hop scenarios. The proposed algorithms in the multi-hop scenario were better at all simulations, providing a lower SER and better channels estimations. / Sistemas de comunicações cooperativas são um importante campo de pesquisa atualmente devido às vantagens que oferecem, como o aumento da potência recebida, melhor qualidade de sinal, e ganhos de diversidade espacial. Particularmente, sitemas multi-saltos são uma importante parte das comunicações cooperativas, uma vez que tais sistemas precisam de menos potência de transmissão se comparados a sistemas diretos. Por outro lado, sistemas MIMO (Multiple-Input Multiple-Output) estão presentes em diversos padrões de comunicação, provendo algumas vantagens, como ganhos de multiplexação espacial. Com base nesse cenário, o presente trabalho propõe dois receptores semi-cegos baseados no pro- duto de Kronecker, que estimam conjuntamente os símbolos e os canais de um sistema AF (Amplify- and-Forward) MIMO cooperativo com multiplos saltos (O protocolo AF é bastante usado, devido a sua grande performance e fácil implementação). É considerado um esquema de transmissão usando uma codificação simplificada KRST (Khatri-Rao Space-Time) na fonte, combinada com um esquema AF no relays. É mostrado que o tensor de terceira ordem dos sinais recebidos pelo destino satisfazem uma decomposição tensorial PARATUCK-(K+1), em que K é o número de relays. Esse modelo tensorial permite uma estimação semi-cega dos símbolos e canais, com o uso de alguns símbolos pilotos. O primeiro algoritmo, chamado de Least-Squares Kronecker-Factorization (LS-KF), é baseado em uma fatorização da matrix do produto de Kronecker entre as matrizes de símbolos e canal. Já o outro algoritmo, chamado de Least-Squares Kronecker-Rearrangement (LS-KR), é baseado no re- arranjo dessa matrix do produto de Kronecker, com o objetivo de conseguir uma matrix com rank 1. A performance desses receptores é avaliada através do resultado de simulações computacionais, provando sua eficiência em estimar os canais e prover uma baixa SER (Symbol Error Rate). Os algo- ritmos propostos no cenário multi-hop são comparados um com o outro e com os cenários two-hop e three-hop. Os algoritmos propostos no cenário multi-hop tiveram melhores performance em todas as simulações, resultando numa menor SER e melhores estimações dos canais.

CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / Ericsson Brasil / O aumento da demanda por serviÃos ricos em multimÃdia e a escassez do espectro eletromagnÃtico tÃm motivado a pesquisa de tecnologias capazes de aumentar a capacidade de sistemas sem fio sem requerer espectro adicional. Nesse contexto, comunicaÃÃes Dispositivo-a-Dispositivo (D2D, do inglÃs Device-to-Device) representam uma tecnologia promissora. Ao permitir comunicaÃÃo direta e de baixa potÃncia entre os dispositivos, comunicaÃÃes D2D levam a um maior e mais inteligente reuso dos recursos de rÃdio, permitindo um descongestionamento da rede de transporte de dados. Como resultado, a capacidade total do sistema e especialmente a eficiÃncia espectral sÃo aumentadas; e a proximidade entre os dispositivos permitem transferÃncias de dados com baixo atraso e altas taxas de dados, sem requerer potÃncia extra da bateria dos dispositivos. Entretanto, com o objetivo de tornar real os potenciais ganhos de comunicaÃÃes D2D como uma rede secundÃria da celular (primÃria), algumas questÃes chave precisam ser controladas. Assumindo que os dispositivos se comunicando estÃo cientes um do outro, a condiÃÃo do enlace (canal) deve ser avaliada. Caso seja benÃfica, tÃcnicas de GestÃo de recursos de rÃdio (RRM, do inglÃs Radio Resource Management) sÃo empregadas para que a interferÃncia co-canal causada nos dispositivos celulares seja mitigada. Tais tÃcnicas podem ser resumidas como: agrupamento, seleÃÃo de modo e controle de potÃncia. Nessa dissertaÃÃo, eu foco a minha atenÃÃo para RRM em comunicaÃÃes D2D subjacentes a redes LTE, e para as principais tÃcnicas de RRM para mitigar a interferÃncia co-canal. Objetivando a reduÃÃo da interferÃncia intra-celular e na melhoria da eficiÃncia espectral, eu formulo um problema conjunto de agrupamento e controle de potÃncia. Entretanto, devido à sua complexidade eu proponho mÃtodos sub-Ãtimos para agrupar usuÃrios celulares e D2D com o objetivo de minimizar a interferÃncia intra-celular, levando em conta a ortogonalidade espacial entre os usuÃrios que compartilham o recurso. AlÃm disso, eu analiso mÃtodos para decidir se um candidato D2D deveria se comunicar diretamente ou de modo convencional atravÃs da estaÃÃo rÃdio-base (eNB, do inglÃs Evolved Node B). Os resultados mostram que comunicaÃÃes D2D conseguem melhorar a eficiÃncia espectral do sistema e que a maioria dos ganhos pode ser alcanÃada agrupando de forma adequada os usuÃrios para compartilhar recursos baseando-se em projeÃÃes sucessivas e ortogonais, assim como combinando diferentes mÃtricas de compatibilidade espacial. AlÃm disso, nessa dissertaÃÃo eu argumento que tecnologias D2D podem ser usadas para aumentar ainda mais a eficiÃncia espectral e energÃtica se os parÃmetros chave dos algoritmos de RRM forem adequadamente estendidos para comunicaÃÃes D2D em mÃltiplos saltos. Especificamente, eu proponho um novo algoritmo distribuÃdo de controle de potÃncia baseado em maximizaÃÃo da utilidade que à capaz de equilibrar eficiÃncia espectral e energÃtica, enquanto leva em consideraÃÃo a seleÃÃo de modo e restriÃÃes na alocaÃÃo de recursos inerentes à integraÃÃo do ambiente celular-D2D. Os resultados numÃricos mostram que comunicaÃÃes D2D em mÃltiplos saltos combinadas com o algoritmo de controle de potÃncia proposto sÃo Ãteis nÃo apenas para colher os potenciais ganhos identificados na literatura, mas tambÃm para estender a cobertura de redes celulares. / The increasing demand for fast multimedia services and the scarcity of electromagnetic spectrum has motivated the research of technologies able to increase the capacity of wireless systems without requiring additional spectrum. In this context, Device-to-Device (D2D) communication represents a promising technology. By enabling direct and low-power communication among devices, D2D communication leads to an increased and intelligent spatial reuse of radio resources allowing to offload the data transport network. As a result, the overall system capacity and specially the spectral efficiency is increased; and the proximity between devices allows data transfer with low delays and high rates without requiring extra power from devicesâ batteries. However, in order to realize the potential gains of D2D communications as a secondary network of the cellular (primary) one, some key issues must be tackled. Assuming that the communicating devices are aware of each other, the actual link (channel) conditions must be evaluated. If beneficial, Radio Resource Management (RRM) techniques would be employed so that the co-channel interference caused in cellular devices would be mitigated. Such techniques may be summarized as: grouping, mode selection, and power control. In this thesis, I focus my attention on the RRM for D2D communications underlaying a Long Term Evolution (LTE)-like network, and the main RRM techniques to mitigate the co-channel interference. Aiming at the reduction of the intra-cell interference and at the improvement of spectral efficiency, I formulate a joint grouping and power allocation problem. However, due to its complexity I propose suboptimal methods to group cellular and D2D User Equipments (UEs) with the goal of minimizing intra-cell interference, taking into account spatial orthogonality between the UEs that share the same resources. In addition, I analyze methods to decide if D2D-capable UEs should communicate directly to one another or in the conventional way via the Evolved Node B (eNB). The results show that D2D communications can improve the spectral efficiency of the system and that most of this improvement can be achieved by suitably grouping the UEs for sharing resources based on successive orthogonal projections and matching different spatial compatibility metrics. Moreover, in this thesis I argue that D2D technology can be used to further increase the spectral and energy efficiency if the key D2D RRM algorithms are suitably extended to support network assisted multi-hop D2D communications. Specifically I propose a novel, distributed utility maximizing power control (PC) scheme that is able to balance spectral and energy efficiency while taking into account mode selection and resource allocation constraints that are important in the integrated cellular-D2D environment. The analysis and numerical results indicate that multi-hop D2D communications combined with the proposed PC scheme can be useful not only for harvesting the potential gains previously identified in the literature, but also for extending the coverage of cellular networks.

Physical layer network coding (PNC) was proposed under the two-way relay hannel (TWRC) scenario, where two sources exchange information aided by a relay. PNC allows the two sources to transmit to the relay simultaneously, where superimposed signals at the relay can be mapped to network-coded symbols and then be broadcast to both sources instead of being treated as interference. Concurrent transmissions using PNC achieve a higher spectrum efficiency compared to time division and network coding solutions. Existing research mainly focused on the symmetric PNC designs, where the same channel coding and modulation configurations are applied by both sources. When the channel conditions of the two source-relay links are asymmetric or unequal amount of data are exchanged, heterogeneous modulation PNC designs are necessary. In additional, the design and optimization of multi-hop PNC, where multiple relays forming a multi-hop path between the two sources, remains an open issue. The above issues motivate the study of this dissertation. This dissertation investigates the design of heterogeneous modulation physical layer network coding (HePNC), the integration of channel error control coding into HePNC, the combination of HePNC with hierarchical modulation, and the design and generalization of multi-hop PNC. The contributions of this dissertation are four-fold. First, under the asymmetric TWRC scenario, where the channel conditions of the two source-relay links are asymmetric, we designed a HePNC protocol, including the optimization of the adaptive mapping functions and the bit-symbol labeling, to minimize the end-to-end BER. In addition, we developed an analytical framework to derive the BER of HePNC. HePNC can substantially enhance the throughput compared to the existing symmetric PNC under the asymmetric TWRC scenario. Second, we investigated channel coded HePNC and integrated the channel error control coding into HePNC in a link-to-link coding, where the relay tries to decode the superimposed codewords in the multi-access stage. A full-state sum-product decoding algorithm is proposed at the relay based on the repeat-accumulate codes to guarantee reliable end-to-end communication. Third, we proposed hierarchical modulation PNC (H-PNC) under asymmetric TWRC, where additional data exchange between the relay and the source with the relatively better channel condition is achieved in addition to that between the two end sources, benefiting from superimposing the additional data flow on the PNC transmission. When the relay also has the data exchange requirement with the source with a better source-relay channel, H-PNC outperforms HePNC and PNC in terms of the system sum throughput. Fourth, we designed and generalized multi-hop PNC, where multiple relays located in a linear topology are scheduled to support the data exchange between two end sources. The impact of error propagation and mutual interference among the nodes are addressed and optimized. The proposed designs outperform the existing ones in terms of end-to-end BER and end-to-end throughout. / Graduate