<p>Much work has been done in simulating traditional cellular networks. But with the incoming of ad-hoc network technology, the next generation networks will employ hybrid network architectures using both cellular and ad-hoc networking concepts. </p><p>We investigate how to create a simulator being able to simulate a hybrid wireless network. This involves setting up a cellular network and an ad-hoc network respectively. However, the most important thing is how to integrate them seamlessly. </p><p>Fortunately, there has already been a simulator called SIMRA which simulates a UMTS cellular network. Therefore, this thesis work is greatly simplified as how to extend and improve SIMRA to implement a simulator for hybrid wireless network. We selected J-sim as the developing platform for our simulator and our development was greatly based on the wireless package provided by the latest version of J-sim. </p><p>To evaluate the new simulator, different resource allocation algorithms were run against it and the results were compared to those generated by earlier extensions to SIMRA under the same simulation settings. It showed that the resource allocation algorithms behaved similarly under the hybrid wireless network environment. Nevertheless, there are some discrepancies in behaviors of algorithms used for evaluation that still need to be studied.</p>

Much work has been done in simulating traditional cellular networks. But with the incoming of ad-hoc network technology, the next generation networks will employ hybrid network architectures using both cellular and ad-hoc networking concepts. We investigate how to create a simulator being able to simulate a hybrid wireless network. This involves setting up a cellular network and an ad-hoc network respectively. However, the most important thing is how to integrate them seamlessly. Fortunately, there has already been a simulator called SIMRA which simulates a UMTS cellular network. Therefore, this thesis work is greatly simplified as how to extend and improve SIMRA to implement a simulator for hybrid wireless network. We selected J-sim as the developing platform for our simulator and our development was greatly based on the wireless package provided by the latest version of J-sim. To evaluate the new simulator, different resource allocation algorithms were run against it and the results were compared to those generated by earlier extensions to SIMRA under the same simulation settings. It showed that the resource allocation algorithms behaved similarly under the hybrid wireless network environment. Nevertheless, there are some discrepancies in behaviors of algorithms used for evaluation that still need to be studied.

Hybrid Wireless Networks (HWNs) are composite networks comprises of different technologies, possibly with overlapping coverage. Users with multimode terminals in HWNs are able to initiate connectivity that best suits their attributes and the requirements of their applications. There are many complexities in hybrid wireless networks due to changing data rates, frequency of operation, resource availability, QoS and also, complexities in terms of mobility management across different technologies. A superstore is a very large retail store that serves as a one-stop shopping destination by offering a wide variety of goods that range from groceries to appliances. It provide all types services such as banking, photo center, catering, etc. The good examples of superstores are: Tesco (hypermarkets, United Kingdom), Carrefour(hypermarkets, France), etc. Generally, the mobile customer communicates with superstore server using a transaction. A transaction corresponds to a finite number of interactive processes between the customer and superstore server. A few superstore transactions, examples are, product browsing, Technical details inquiry, Financial transactions, billing, etc. This thesis aims to design and develop the following schemes to solve some of the above indicated problems of a hybrid wireless superstore network: 1 Transaction based bandwidth management. 2 Transaction-based resource management. 3 Transaction-based Quality of Service management. 4. Transactions-based topology management. We, herewith, present these developed schemes, the simulation carried out and results obtained, in brief. Transaction-based bandwidth management The designed Transaction-Based Bandwidth Management Scheme (TB-BMS) operates at application-level and intelligently allocates the bandwidth by monitoring the profit oriented sensitivity variations in the transactions, which are linked with various profit profiles created over type, time, and history of transactions. The scheme mainly consists of transaction classifier, bandwidth determination and transactions scheduling modules. We have deployed these scheme over a downlink of HWNs, since the uplink caries simple quires from customers to superstore server. The scheme uses transaction scheduling algorithm, which decides how to schedule an outgoing transaction based on its priority with efficient use of available BW. As we observe, not all superstore transactions can have the same profit sensitive information, data size and operation type. Therefore, we classify the superstore transactions into four levels based on profit, data size, operation type and the degree of severity of information that they are handling. The aim of transaction classification module is to find the transaction sensitivity level(TSL) for a given transaction. The bandwidth determination module estimates bandwidth requirement for each of the transactions. The transactions scheduling module schedules the transactions based on availability of bandwidth as per the TSL of the transaction. The scheme schedules the highest priority transactions first, keeping the lowest priority transaction pending. If all the highest priority transactions are over, then it continues with next priority level transactions, and so on, in every slot. We have simulated the hybrid wireless superstore network environment with WiFi and GSM technologies. We simulated four TSL levels with different bandwidth. The simulation under consideration uses different transactions with different bandwidth requirements. The performance results describe that the proposed scheme considerably improves the bandwidth utilization by reducing transaction blocking and accommodating more essential transactions at the peak time of the business. Transaction-based resource management In the next work, we have proposed the transaction-based resource management scheme (TB-RMS) to allocate the required resources among the various customer services based on priority of transactions. The scheme mainly consists of transaction classifier, resource estimation and transactions scheduling modules. This scheme also uses a downlink transaction scheduling algorithm, which decides how to schedule an outgoing transaction based on its priority with efficient use of available resources. The transaction-based resource management is similar to that of TB-BMS scheme, except that the scheme estimates the resources like buffer, bandwidth, processing time for each of transaction rather than bandwidth. The performance results indicate that the proposed TB-RMS scheme considerably improves the resource utilization by reducing transaction blocking and accommodating more essential transactions at the peak time. Transaction-based Quality of Service management In the third segment, we have proposed a police-based transaction-aware QoS management architecture for the downlink QoS management. We derive a policy for the estimation of QoS parameters, like, delay, jitter, bandwidth, transaction loss for every transaction before scheduling on the downlink. We use Policy-based Transaction QoS Management(PTQM) to achieve the transaction based QoS management. Policies are rules that govern a transaction behavior, usually implemented in the form of if(condition) then(action) policies. The QoS management scheme is fully centralized, and is based on the ideas of client-server interaction. Each mobile terminal is connected to a server via WiFi or GSM. The master policy controller (MPDF) connects to the policy controller of the WiFi network (WPDF)and the GSM policy controller(PDF). We have considered the simulation environment similar to earlier schemes. The results shows that the policy-based transaction QoS management is improves performance and utilizes network resources efficiently at the peak time of the superstore business. Transactions-Aware Topology Management(TATM) Finally, we have proposed a topology management scheme to the superstore hybrid wireless networks. A wireless topology management that manages the activities and features of a wireless network connection. It may control the process of selecting an available access points, authentication and associating to it and setting up other parameters of the wireless connection. The proposed topology management scheme consists of the transaction classifier, resource estimation module, network availability and status module and transaction-aware topology management module. The TATM scheme is to select the best network among available networks to provide transaction response(or execution). We have simulated hybrid wireless superstore network with five WiFi and two GSM technologies. The performance results indicate that the transaction-based topology management scheme utilizes the available resources efficiently and distributed transaction loads evenly in both WiFi and GSM networks based on the capacity.