Microfinance has spread rapidly since the 1970s and gained a lot of international attention. Advocates mean it is a good way to reduce poverty, but still there is no consensus within the research about the impacts of microfinance and its contribution to poverty reduction.The aim of this study is to assess the members’ perceptions about the impacts of the rural member-based microfinance institutions (MFIs), Savings and Credit Cooperative Societies (SACCOS) and Village Community Bank (VICOBA), on members’ socio-economic situation as well as their perceptions about the contribution to poverty reduction and to identify potential obstacles. The study is mainly based on individual semi-structured interviews with members of SACCOS and VICOBA conducted between February and April 2012 in Babati district Tanzania and earlier research and studies within the area of microfinance and poverty reduction make up the theoretical framework. There is a general agreement among the members interviewed that these MFIs have positive impacts on their socio-economic situation. The results show that it helps to meet consumption needs, pay school fees, run small businesses, increase and diversify the income and the majority also believes that it can be a useful tool for poverty reduction. However, it doesn’t lead to poverty reduction automatically, it depends on how the loans are used and this study identifies several obstacles for SACCOS and VICOBA to be more effective and contribute more to poverty reduction. The main obstacles found are low repayment status, lack of capital and lack of education in both entrepreneurship and how these MFIs operate.

This study is about Corporate Social Responsibility (CSR) strategy, sustainable thinking and practices at the Co-operative. The main focus had been the Food store of Co-op. The practices are assessed to see whether Co-op is doing business activities based on the pillars of ethical code of conduct that they have publically reported. The study builds up by presenting an overview of various businesses that are operating ethically under the title of the Cooperative group. The challenge of Co-op is to be ethical, responsible, and aggressive in delivering value to all the stakeholders namely members and customers. This has to be done for the sustainable competitive advantage and growth of the business. It has been noted that despite being the pioneer in Fair trade products, Co-op food faced problems on customer and employees’ level. There were the cases of employee harassment and unreasonable behaviour of customers in attempting to buy beer and age restricted products. One customer level, they considered Co- op good for daily usage items and expressed their concern product prices, variety and delivery options. The employees had a mix response related to this issue and they mostly responded that Co-op was a better place to shop and had better service. The views of managers and customers coincided on many occasions that reflected the awareness of managers about customers’ behaviour. The audit of suppliers of grocery products had been the concern as it was revealed that Co-op food sourced them from other countries like Spain. Therefore, suppliers’ audit became vital for behaving responsibly and having sustainable business practices that are profitable without risk of accusations. This is vital as Co-op food has branded itself as one of the green retailers in UK. Moreover, there are traces of green washing and green marketing as observed by us in their reports and website. This practice is considerably as Peter Marks himself said that customer trust is the key to success after economic crunch.

We consider a decentralized, two-echelon supply chain where the upper echelon --the supplier-- bears the inventory risk. To service the retailers, the supplier either keeps inventory reserved for each of her customers or else pools inventory to share among her customers. The common insight regarding inventory pooling is that it reduces costs and so increases profits for the supply chain party carrying inventory. However, it has recently been shown that inventory pooling may indeed reduce the total supply chain profits. We further show that inventory pooling may reduce supply chain profits even under traditional service contracts based on the frequently invoked measure of service, probability of stock-out. We model the inventory transactions among the retailers and the supplier as a cooperative game. The players have the option of reserving inventory or forming inventory-pooling coalitions. The total profit of the coalitions is allotted to the players using a profit-sharing mechanism based on Shapley value. We analyze the properties of the proposed profit-sharing scheme in two steps. We first consider a stylized model with two retailers who are not necessarily identical. Then we extend the analysis to an arbitrary number of identical retailers. In both cases, we assume the demand across retailers is independent. We find that the Shapley value allocations coordinate the supply chain and are individually rational. However for more than two retailers, they may not be in the core. Even when they satisfy all the stability properties, including membership in the core, they may be perceived unfair since a player's allocation can exceed his contribution to the total supply chain profit. In addition to analyzing the stability properties of the proposed allocation mechanism, we are also interested in the types of behavior the mechanism induces in the players. We find that the retailers prefer pooling partners with either very high or low service level requirements and the supplier prefers retailers with low service requirements since this gives her the ability to maximize her profit allocation. Finally, we analyze the effects of demand variance on the allocations and the profitability of strategic retailer coalitions.

In this thesis, we consider the uplink of a cooperative code division multiple access (CDMA) network, where users cooperate by relaying each other¡¦s messages to the base station. The sources adopt CDMA to share the informations offered by relays. In general, spreading waveforms of sources are not orthogonal to each others due to pratical design issues of CDMA network. Therefore, the source signals will suffer from multiple access interference (MAI) at the relays and destination. The MAI results in the increase of bit error rate increased, and diminishes the cooperative network diveristy gains. In order to mitigate MAI, the decorrelating multiuser detection and zero-forcing precoder have been commonly adopted. But, the decorrelating multiuser detection causes noise enhancement, while the zero-forcing precoder causes power expansion. In this thesis, we adopt relay-assisted decorrelating multiuser detector (RAD-MUD) to mitigate MAI as proposed in [1].In this scheme, the relays perform half of decorrelating operation and the destination performs the other half. In this way, neither noise enhancement nor power expansion will occur. However, in the reference [1], the authers assume the transmission is synchronous between sources and relays. The assumption is unrealistic, because it is difficult to achieve synchronization between all sources and relays due to various propagation delays. In this thesis, we extend the research in [1] and relax restriction of synchronization between all sources and relays. Besides, we also adopt cooperative strategies such as transmit beamforming or selective relaying to enhance system performance. Compared with other¡¦s multiuser detection schemes, we show that the proposed schemes can effectively reduce the bit error rate.

In cooperative communications systems, multiple relays selection scheme and adaptive relay selection scheme are usually adopted. In both schemes, the system makes selections based on instantaneous channel status. However, such schemes have an extremely high computational complexity. In particular, when the channels experience fast fading, the systems do not have sufficient to make a correct decision. In this thesis, statistical channel properties are utilized in deciding whether cooperative transmission should be adopted or not. In our investigations, the cooperative mechanism includes direct transmission (DT), decode-and-forward (DF) relaying and amplify-and-forward (AF) relaying. The Ergodic capacity is adopted throughout the theoretical analyses. In addition, a number of approximated thresholds are derived to assist the decision process. Simulation experiments are conducted to verify the derived results. It is shown that the proposed transmission scheme using the cooperative thresholds is effective in deciding when the cooperative communication is necessary.

In this thesis, we study the effect of channel estimation on the performance of distributed space-time coding (DSTC) in amplify-and-forward (AF) cooperative networks. The relay based transmission takes two phase. In phase I, the source transmits a block of symbols, which include training symbols and data to destination. After receiving signals at relay, the DSTC is adopted to re-encode signals in order to achieve diversity gain at relay nodes. At destination, the signals received in two phase are combined and used to detected data symbols. In the thesis, for AF cooperative networks, the signal received at destination is effected the multiplication of channel coefficients on the source to relay and relay to destination links. Before detection, channel coefficients of all links need to be estimated. We propose a semiblind method to estimate the channel coefficients of direct link and the relay links. The semi-blind channel estimation scheme, exploits a small number of training symbols and second-order statistics of received signals. To improve the detection quality, the channel estimation is modified by treating the detected symbols as extra training symbols. Through simulation, it shows that the proposed channel estimation and the modification leads to obvious performance improvement.

This thesis proposes a strategy for enhancing the efficiency of scalable H.264/AVC video transmission over multi-input multi-output (MIMO) and cooperative communication systems. For scalable video coding (SVC) transmission over MIMO wireless systems, a channel selection algorithm is used to enhance transmission rate. The proposed algorithm allows SVC layers to select channels individually in wireless MIMO systems based on channel state information for transmission rate enhancement. Here, this difficult problem is converted into a mathematical optimization problem to improve SVC performance during video transmission. Experimental results show that the proposed method achieves a higher transmission rate over MIMO systems compared to the existing scheme. For SVC transmission over cooperative communication systems, the algorithm allows each SVC layer to choose an appropriate relay based on channel conditions and SVC layer priority. Thus, SVC data is protected effectively. Experimental results show that video quality obtained by the algorithm exceeds that of non-cooperative systems.

In this thesis, we investigate partner selection schemes in multiuser cooperative networks. In networks, cooperative partners adopt coded cooperation to forward signals. Among the literature, two classes of two namely, centralized partner selections and distributed partner selections, have been proposed to select appropriate relays. Centralized partner selection is able to achieve the global optimization than distributed partner selection. However, centralized partner selections require high complexity, and global channel state information, which demands large amount of overhead and waste radio resources. Especially when the size of network increases, the cost to search appropriate relay for each user dramatically increases. Hence, we consider distributed partner selection scheme in the thesis. Among the existing work, fixed priority selection algorithm is a distributed partner selection algorithm strategy; where partner assignment is based on node indices do not include any channel information. To enhance performance, we exploit the geographical information of all users. Different from other distributed partner selection schemes, we adopt the method of Carrier Sense Multiple Access to exchange local information. We proposed coverage search algorithm, nearest source search algorithm and nearest middle-point search algorithm, the serve as the criteria of partner selection. The contributions of this thesis are to raise SNR, increase the probability that the achievable rate is great than the data rate in the distributed partner selection scheme, and enhance system performance.

Cooperative communications is an emerging technique that has spatial diversity inherent in wireless multiuser communication systems without multiple antennas at each node. Most studies in the literature assume that users acting as the relays are normally operated and trustworthy, which, however, may not always be true in practice. This thesis considers the design of robust cooperative communication in physical layer for combating relay misbehaviors. This thesis considers both models in which the cooperative communications is with direct path (WDP) and without direct path (WODP). Two signal-correlation-detection rules for both WDP and WODP are proposed, respectively. Utilizing the proposed signal-correlation-detection mechanism, the destination identifies the misbehaving relays within the cooperative communication network and then excludes their transmitting messages when performing the diversity combining to infer the symbols of interest sent by the source. The proposed signal-correlation-detection rules are optimally designed in accordance with either the criterion of the minimization of the probability of misbehavior misidentification or the criterion of the maximum generalized likelihood detector. In addition, this thesis also provides the BER analysis of the cooperative communications employing the proposed misbehaving relay detectors. The simulation result demonstrates that the proposed schemes have excellent robust performance when the relay misbehavior is present in the cooperative communication networks.

Cooperative systems exploit spatial diversity to improve communication quality. But system performances could be severely degraded in the existance malicious relay nodes. In this thesis, we consider a two-relay decode-and-forward (DF) cooperative network. Relay nodes adopt Orthogonal Space Time Block Code (OSTBC) to achieve spatial diversity. Assume that relay nodes may misbehave with a certain probability. If a relay is malicious, it will garble transmission signals, resulting in severe damage to system performance. In the literature, detecting malicious relays requires perfect channel state information. However, misbehavior of the relay will first lead to inaccurate channel estimation. Therefore, we propose a novel detecting misbehavior scheme to deal with the dilemma. Since misbehavior of relays influences statistical properties of the estimated channel coefficients, destination can detect misbehaving by comparing the distribution of channel estimates. The most important of all is that we don¡¦t need channel state information to enhance detecting performance. Through simulation results, we verify proposed scheme can detect misbehavior effectively without channel state information. Compared with signal-to-noise ratio, the number of received tracing symbols has more significant impact on detecting misbehavior of the relay.