Multihop cellular networks (MCNs) have drawn tremendous attention due to its high throughput and extensive coverage. However, there are still three issues not well addressed. With the existence of relay stations (RSs), how to efficiently allocate frequency resource to relay links becomes a challenging design issue. For mobile stations (MSs) near the cell edge, cochannel interference (CCI) become severe, which significantly affects the network performance.
Furthermore, the unbalanced user distribution will result in traffic congestion and inability to guarantee quality of service (QoS). To address these problems, we propose a quantitative study on adaptive resource allocation schemes by jointly considering interference coordination (IC) and load balancing (LB) in MCNs.
In this paper, we focus on the downlink of OFDMA-based MCNs with time division duplex (TDD) mode, and analyze the characteristics of resource allocation according to IEEE 802.16j/m specification. We also design a novel frequency reuse scheme to mitigate interference and maintain high spectral efficiency, and provide practical LB-based handover mechanisms which can evenly distribute the traffic and guarantee users’ QoS.
The future wireless cellular networks, such as 3GPP advanced long term evolution (LTE-Advanced) and IEEE 802.16m systems, will adopt orthogonal frequency division multiple access (OFDMA) technology for multihop cellular networks (MCNs). OFDMA is regarded as the most promising physical layer technology for the fourth generation (4G) wireless networks. New relay strategies and technologies are proposed to provide services with extended coverage and higher data rate. Fixed relay stations (RSs) with fewer functionalities than base stations (BSs) can be deployed to overcome poor channel conditions while maintaining low infrastructure cost. Nevertheless, MCNs have inherent drawbacks, for example, extra radio resource are required on relay links (BS-RS links). Therefore, well-designed radio resource allocation schemes are crucial for MCNs to effectively exploit the benefit of RSs, while overcoming the disadvantages.
Since RSs always utilizes the same spectrum as MSs or BSs, cochannel interference (CCI) will be closely related to the radio resource allocation schemes in MCNs due to the intercell and intracell frequency reuse. OFDMA systems should employ frequency planning for better cell edge performance and the ease of interference management. Traditional single-hop cellular networks (SCNs) typically employ the frequency reuse pattern with factor of 3 or 7 to reduce CCI, which results in low spectral efficiency. As we all know, high data rate is one of the desired features of the future cellular networks. It requires a highly efficient utilization of the available spectrum. Frequency reuse with factor of 1 is likely to be used in LTE-Advanced and IEEE 802.16m systems, aiming at improving the spectral efficiency. However, the CCI using this frequency planning causes severe performance degradation at cell boundaries. (WiMAX) Forum, the frequency reuse pattern can be denoted as N _ S _ K, which means that the networks are divided into clusters of N cells (each cell in the cluster has a different frequency band), with S sectors and K different frequency bands per cell. According to these reuse patterns, all available spectrum is assigned to all sector-BSs in the reuse pattern of 1 _ 3 _ 1, whereas each sector-BS uses only one third of the total frequency bands in the reuse pattern of 1 _ 3 _ 3. The CCI level is higher in the former, whereas the spectral efficiency is lower in the latter. If 1 _ 3 _ 3 is used in MCNs, the spectral efficiency will be much lower because extra frequency resource has to be allocated to relay links. If 1 _ 3 _ 1 is used in MCNs, the frequency reuse scheme is more important in a multicell scenario. Compared with BSs deployed at the cell center, RSs deployed at the cell edge cause serious interference because RSs are closer to the mobile stations (MSs) in the adjacent cells than those BSs.
In the existing literature, there are several works about reducing CCI in MCNs. In, several static resource allocation schemes with different partitions and reuse factors are discussed. The CCI in these schemes is analyzed in a multicell scenario. In, a relay-based orthogonal frequency planning strategy is proposed to improve cell edge performance. In, fractional frequency reuse (FFR) is extended to MCNs as a compromise solution to reduce CCI while maintaining the sector frequency reuse factor as 1. The main idea of FFR is to adopt frequency reuse 1 _ 3 _ 1 at the cell center to maximize the network spectral efficiency while harnessing frequency reuse 1 _ 3 _ 3 at the cell edge to alleviate CCI, the minimum CCI has been achieved by adjusting the transmission (Tx) power at BSs and RSs under orthogonal frequency resource allocation. The essence of these works is to use partial frequency bands while maintaining frequency orthogonal at the cell edge and the remaining frequency bands at the cell center.
Moreover, there are several static frequency allocation schemes proposed in the aforementioned works, which fit for uniform traffic distribution only. In reality, users are not evenly distributed among cells. Too many users accessing one station (BS or RS) yields load imbalance in MCNs. Such an imbalance could severely affect the performance of hot spot areas, which may not meet the users’ quality of service (QoS) requirements. This is another major reason for system performance degradation. To guarantee users’ QoS, therefore, load balancing (LB) should be adopted along with IC for MCNs.
LB has been widely studied in SCNs and heterogeneous networks (HetNets). For SCNs, resource allocation schemes have to work in conjunction with the connection admission control (CAC) mechanisms, which determines, based on available resource and users’ QoS, whether to admit an incoming connection to a particular cell or to reject it in the current cell, but to switch the user to an adjacent non congested cell through a handover mechanism. Here, the corresponding handover mechanism is not executed due to position change of users, but due to the lack of resource in the original cell. As important methods in LB, the cell breathing and load-ware handover are proposed. The idea is that if a cell is heavily congested, the adjacent noncongested cell may expand the coverage and accommodate more users by raising transmission power. In a scheme jointly considering IC and LB is designed to improve the weighted sum of data rates in multicell networks. The problem is NP-hard and then develop a local-improvement-based algorithm to solve it. These works suggest not only to use higher transmission power at the adjacent cell stations, but also report continually a large amount of information related to signal quality and traffic load in the surrounding cells, to the mobile switch center (MSC), to calculate the best connection to the BS. Apparently, this would increase the system overhead and management complexity. For HetNets, an integrated cellular and ad hoc relay (iCAR) system has been proposed, in which some users can be switched to adjacent cells through ad hoc RSs and the spare resource are then acquired by incoming users. However, this type of LB only works with HetNets.
HetNets intend to change the traditional system architecture of cellular networks, while MCNs only attempt to improve the network performance of the traditional cellular networks through the use of RSs. It is noticeable that MCNs differ from Het Nets in the following few characteristics: 1) RSs are important add-on communications facilities of cellular networks, which also share the same spectrum with BSs;
2) BSs and RSs are connected through wireless radio interfaces;
3) the users associated with an RS need to access BS ultimately, which may ask for two-hop transmissions to deliver data.
With the deployment of RSs in MCNs, more handover opportunities arise, leading to better resource management and performance gain. This paper focuses on how to switch the connections from congested stations to non congested stations and increase the available frequency resource for congested stations to achieve LB. In a cell, the traffic load information of RSs as well as link qualities between RSs and MSs are reported to BS by RSs. The BS is directly responsible for performing handover mechanisms in each sector. This method does not require to collect and process all kinds of information for a group of cells, which can reduce the complexity of the system implementation and guarantee QoS for users in hot spots.
The main contributions of this paper can be summarized as follows: We provide a quantitative study on an adaptive resource allocation scheme by jointly considering IC and LB in MCNs. We also present a novel frequency reuse scheme to mitigate interference and maintain high spectral efficiency, and propose practical LB-based handover mechanisms which can evenly distribute the traffic load and guarantee users’ QoS. Extensive simulations demonstrate that our proposed schemes can provide higher throughput and accommodate more QoS-guaranteed users than what conventional SCNs can do.
1.3 LITRATURE SURVEY
OPPORTUNITIES AND CHALLENGES IN OFDMA-BASED CELLULAR RELAY NETWORKS: A RADIO RESOURCE MANAGEMENT PERSPECTIVE
PUBLICATION: M. Salem, A. Adinoyi, H. Yanikomeroglu, and D. Falconer, IEEE Trans. Vehicular Technology, vol. 59, no. 5, pp. 2496-2510, Jan. 2010.
The opportunities and flexibility in relay networks and orthogonal frequency-division multiple access (OFDMA) make the combination a suitable candidate network and air-interface technology for providing reliable and ubiquitous high-data-rate coverage in next-generation cellular networks. Advanced and intelligent radio resource management (RRM) schemes are known to be crucial toward harnessing these opportunities in future OFDMA-based relay-enhanced cellular networks. However, it is not very clear how to address the new RRM challenges (such as enabling distributed algorithms, intra-cell/inter-cell routing, intense and dynamic co-channel interference (CCI), and feedback overhead) in such complex environments comprising a plethora of relay stations (RSs) of different functionalities and characteristics. Employment of conventional RRM schemes in such networks will highly be inefficient if not infeasible. The next-generation networks are required to meet the expectations of all wireless users, irrespective of their locations. High-data-rate connectivity, mobility, and reliability, among other features, are examples of these expectations. Therefore, fairness is a critical performance aspect that has to be taken into account in the design of prospective RRM schemes. This paper reviews some of the prominent challenges involved in migrating from the conventional cellular architecture to the relay-based type and discusses how intelligent RRM schemes can exploit the opportunities in relay-enhanced OFDMA-based cellular networks. We identify the role of multiantenna systems and explore the current approaches in literature to extend the conventional schedulers to next-generation relay networks. This paper also highlights the fairness aspect in such networks in the light of the recent literature, provides some example fairness metrics, and compares the performances of some representative algorithms.
INTERFERENCE COORDINATION IN COMPACT FREQUENCY REUSE FOR MULTIHOP CELLULAR NETWORKS
PUBLICATION: Y. Zhao, X. Fang, and Z. Zhao, IEICE Trans. Fundamentals of Electronics, Comm. and Computer Sciences, vol. E93-A, no. 11, pp. 2312-2319, Nov. 2010.
| Continuously increasing the bandwidth to enhance the capacity is impractical because of the scarcity of spectrum availability. Fortunately, on the basis of the characteristics of the multihop cellular networks (MCNs), a new compact frequency reuse scheme has been proposed to provide higher spectrum utilization efficiency and larger capacity without increasing the cost on network. Base stations (BSs) and relay stations (RSs) could transmit simultaneously on the same frequency according to the compact frequency reuse scheme. In this situation, however, mobile stations (MSs) near the coverage boundary will suffer serious interference and their traffic quality can hardly be guaranteed. In order to mitigate the interference while maintaining high spectrum utilization efficiency, this paper introduces a fractional frequency reuse (FFR) scheme into multihop cellular networks, in which the principle of FFR scheme and characteristics of frequency resources configurations are described, then the transmission (Tx) power consumption of BS and RSs is analyzed. The proposed scheme can both meet the requirement of high traffic load in future cellular system and maximize the benefit by reducing the Tx power consumption. Numerical results demonstrate that the proposed FFR in compact frequency reuse achieves higher cell coverage probability and larger capacity with respect to the conventional schemes. |
TECHNICAL SPECIFICATION GROUP RADIO ACCESS NETWORK; PHYSICAL LAYER ASPECTS FOR EVOLVED UNIVERSAL TERRESTRIAL RADIO ACCESS (UTRA)
PUBLICATION: Third Generation Partnership Project, 3GPP Technical Report 25.814 v7.1.0, Sept. 2006.
The justification of the study item was, that with enhancements such as HSDPA and Enhanced Uplink, the 3GPP radio-access technology will be highly competitive for several years. However, to ensure competitiveness in an even longer time frame, i.e. for the next 10 years and beyond, a long-term evolution of the 3GPP radio-access technology needs to be considered. Important parts of such a long-term evolution includes reduced latency, higher user data rates, improved system capacity and coverage, and reduced cost for the operator. In order to achieve this, an evolution of the radio interface as well as the radio network architecture should be considered. Considering a desire for even higher data rates and also taking into account future additional 3G spectrum allocations the long-term 3GPP evolution should include an evolution towards support for wider transmission bandwidth than 5 MHz. At the same time, support for transmission bandwidths of 5MHz and less than 5MHz should be investigated in order to allow for more flexibility in whichever frequency bands the system may be deployed.
OPPORTUNITIES AND CHALLENGES IN OFDMA-BASED CELLULAR RELAY NETWORKS: A RADIO RESOURCE MANAGEMENT PERSPECTIVE
PUBLICATION: M. Salem, A. Adinoyi, H. Yanikomeroglu, and D. Falconer, IEEE
Trans. Vehicular Technology, vol. 59, no. 5, pp. 2496-2510, Jan. 2010.
The opportunities and flexibility
in relay networks and orthogonal frequency-division multiple access (OFDMA)
make the combination a suitable candidate network and air-interface technology
for providing reliable and ubiquitous high-data-rate coverage in next-generation
cellular networks. Advanced and intelligent radio resource management (RRM)
schemes are known to be crucial toward harnessing these opportunities in future
OFDMA-based relay-enhanced cellular networks. However, it is not very clear how
to address the new RRM challenges (such as enabling distributed algorithms,
intra-cell/inter-cell routing, intense and dynamic co-channel interference
(CCI), and feedback overhead) in such complex environments comprising a
plethora of relay stations (RSs) of different functionalities and
characteristics. Employment of conventional RRM schemes in such networks will
highly be inefficient if not infeasible. The next-generation networks are
required to meet the expectations of all wireless users, irrespective of their
locations. High-data-rate connectivity, mobility, and reliability, among other
features, are examples of these expectations. Therefore, fairness is a critical
performance aspect that has to be taken into account in the design of
prospective RRM schemes. This paper reviews some of the prominent challenges
involved in migrating from the conventional cellular architecture to the
relay-based type and discusses how intelligent RRM schemes can exploit the
opportunities in relay-enhanced OFDMA-based cellular networks. We identify the
role of multiantenna systems and explore the current approaches in literature
to extend the conventional schedulers to next-generation relay networks. This
paper also highlights the fairness aspect in such networks in the light of the
recent literature, provides some example fairness metrics, and compares the
performances of some representative algorithms.
CHAPTER 2
2.0 SYSTEM ANALYSIS
2.1 EXISTING SYSTEM:
Existing
literature, there are several works about reducing CCI in MCNs. In, several
static resource allocation schemes with different partitions and reuse factors
are discussed. The CCI in these schemes is analyzed in a multicell scenario in
a relay-based orthogonal frequency planning strategy is proposed to improve
cell edge performance. Fractional frequency reuses (FFR) is extended to MCNs as
a compromise solution to reduce CCI while maintaining the sector frequency
reuse factor as 1. The minimum CCI has been achieved by adjusting the
transmission (Tx) power at BSs and RSs under orthogonal frequency resource
allocation. The essence of these works is to use partial frequency bands while
maintaining frequency orthogonal at the cell edge and the remaining frequency
bands at the cell center.
2.2 PROPOSED SYSTEM:
We propose a quantitative study on adaptive resource allocation schemes by jointly considering interference coordination (IC) and load balancing (LB) in MCNs. In this paper, we focus on the downlink of OFDMA-based MCNs with time division duplex (TDD) mode, and analyze the characteristics of resource allocation according to IEEE 802.16j/m specification. We also design a novel frequency reuse scheme to mitigate interference and maintain high spectral efficiency, and provide practical LB-based handover mechanisms which can evenly distribute the traffic and guarantee users’ QoS.
We provide a quantitative study on an adaptive resource allocation scheme by jointly considering IC and LB in MCNs. We also present a novel frequency reuse scheme to mitigate interference and maintain high spectral efficiency, and propose practical LB-based handover mechanisms which can evenly distribute the traffic load and guarantee users’ QoS. Extensive simulations demonstrate that our proposed schemes can provide higher throughput and accommodate more QoS-guaranteed users than what conventional SCNs.
WMNs, the frequency spectrum is shared and randomly contended by all stations. The access scheme with the lowest overhead is optimal. However, for example, in this paper, a centrally controlled optimal resource allocation for OFDMA-based MCNs is our target.
To provide analytical performance evaluation, we make two assumptions for the remainder of this paper:
1. All users have a single type of data service and thus have the same QoS requirements.
2. All cells/sectors have the same channel conditions, traffic load, and distribution of users.
2.3.1 HARDWARE REQUIREMENT:
CHAPTER 3
3.0 SYSTEM DESIGN
Data Flow Diagram / Use Case Diagram / Flow Diagram
External sources or destinations, which may be people or organizations or other entities
Here the data referenced by a process is stored and retrieved.
People, procedures or devices that produce data. The physical component is not identified.
Data moves in a specific direction from an origin to
a destination. The data flow is a “packet” of data.
There are several common modeling rules when creating DFDs:
3.1 NETWORK ARCHITECTURE DIAGRAM:
3.2 DATAFLOW DIAGRAM:
UML DIAGRAMS:
3.3 USE CASE DIAGRAM:
3.4 CLASS DIAGRAM:
3.5 SEQUENCE DIAGRAM:
3.6 ACTIVITY DIAGRAM:
CHAPTER 4
4.0 IMPLEMENTATION:
JOINT INTERFERENCE COORDINATION AND LOAD BALANCING:
Since traffic load distribution of each
cell/sector affects the system performance significantly, we propose joint IC
and LB (ICLB) for MCNs. The objective is to improve system throughput under the
constraint of the basic requirement on coverage in the cell coverage
probability, is defined as the percentage of area within the cell that has received
SINR above the threshold of the most robust MCS, i.e., QPSK (1/12) modulation.
Therefore, the coverage probability can be estimated to MCNs, increasing
throughput implies that more users’ QoS requirements are met. Therefore, system
throughput is improved and more reliable service is attained. For different
station types, we present two LB mechanisms to improve the system throughput.
4.1 ALGORITHM:
RESOURCE SCHEDULING ALGORITHM:
For relay links, based on the allocation result of the second-hop links, slots should be assigned to first-hop link with proportion to the aggregate data rate of the secondhop link of each RS that the resource allocation to the first-hop link via each RS will end when the first-hop data rate is greater than or equal to the aggregate secondhop data rate. The other slots of RZ are assigned to BS-MS links according to (8). Considering the assignable slots of one frame are limited, the attainable balance of slot allocation determines the ratio of RZ and AZ in the time domain in each frame. The detailed algorithm is shown in Algorithm 1.
4.2 MODULES:
SERVER CLIENT MODULE:
MULTIHOP CELLULAR:
LOAD BALANCING:
RESOURCE SCHEDULING:
OFDMA/TDD:
4.3 MODULE DISCRIPTION:
SERVER CLIENT MODULE:
Client-server computing or networking is a distributed application architecture that partitions tasks or workloads between service providers (servers) and service requesters, called clients. Often clients and servers operate over a computer network on separate hardware. A server machine is a high-performance host that is running one or more server programs which share its resources with clients. A client also shares any of its resources; Clients therefore initiate communication sessions with servers which await (listen to) incoming requests.
MULTIHOP CELLULAR NETWORKS:
Multi-hop cellular network (MCN) is an architecture proposed for wireless communication & MCNs combine the benefits of having a fixed infrastructure of base stations and the flexibility of ad-hoc networks. They are capable of achieving much higher throughput than current cellular systems, which can be classified as single-hop cellular networks (SCNs). This work concentrates on MCNs and SCNs using the IEEE 802.11 standard for wireless LANs.
We provide a general overview of the architecture and the issues involved in the design of MCNs, in particular the challenges to be met in the design of a routing protocol. We extend the work of Lin and Hsu to enhance the throughput of such networks further.
We propose a routing protocol for use in such networks. We conduct extensive experimental studies on the performance of MCNs and SCNs under various load conditions (both TCP and UDP). Then studies clearly indicate that MCNs with the proposed routing protocol are a viable alternative for SCNs, in fact they provide much higher throughput.
LOAD BALANCING NETWORKS:
Wireless sensor networks have received increasing attention in the many military and civil applications of sensor networks; sensors are constrained in onboard energy supply and are left unattended. Energy, size and cost constraints of such sensors limit their communication range. Therefore, they require multi-hop wireless connectivity to forward data on their behalf to a remote command site.
Our performance of an algorithm to network these sensors in to well define clusters with less energy-constrained gateway nodes acting as cluster heads, and balance load among these gateways. Load balanced clustering increases the system stability and improves the communication between different nodes in the system. To evaluate the efficiency of our approach we have studied the performance of sensor networks applying various different routing protocols.
Simulation results shows that
irrespective of the routing protocol used, our approach improves the lifetime
of the system performance of hot spot areas, which may not meet the users’
quality of service (QoS) requirements. This is another major reason for system
performance degradation. To guarantee users’ QoS, therefore, load balancing
(LB) should be adopted along with IC for MCNs.
RESOURCE SCHEDULING:
Resource scheduling can further improve system performance; we then extend the proportional fair (PF) algorithm for MCNs in this section. Besides the PF algorithm, the other two classical scheduling algorithms of round robin (RR) and maximum SINR (MaxSINR) are often applied to cellular networks. In RR algorithm, slots are allocated to the users in the cell coverage in due order and thus seem to be absolutely fair. Nonetheless, it is not efficient since the difference of slot efficiency of users is not taken into consideration.
In MaxSINR algorithm, slots are allocated to the users with the highest SINR at per scheduling instant, which can maximize the system throughput, but it is not fair since the users with low slot efficiency are not guaranteed to obtain slots. The PF algorithm has been investigated in the literature of scheduling in SCNs provides an efficient throughput-fairness tradeoff. In MCNs, the BS is responsible for gathering link information and allocating the available resource to the corresponding links according to the PF algorithm.
OFDMA/TDD NETWORKS:
THE future wireless cellular networks, such as 3GPP advanced long term evolution (LTE-Advanced) and IEEE 802.16m systems, will adopt orthogonal frequency division multiple access (OFDMA) technology for multihop cellular networks (MCNs). OFDMA is regarded as the most promising physical layer technology for the fourth generation (4G) wireless networks. New relay strategies and technologies are proposed to provide services with extended coverage and higher data rate.
OFDMA systems should employ frequency planning for better cell edge performance and the ease of interference management. Traditional single-hop cellular networks (SCNs) typically employ the frequency reuse pattern with factor of 3 or 7 to reduce CCI, which results in low spectral efficiency. As we all know, high data rate is one of the desired features of the future cellular networks. It requires a highly efficient utilization of the available spectrum. Frequency reuse with factor of 1 is likely to be used in LTE-Advanced and IEEE 802.16m systems, aiming at improving the spectral efficiency.
Time division duplex (TDD) frame consists of downlink and uplink subframes. Each subframe is subsequently divided into two time zones which are named as relay zone (RZ) and access zone (AZ), respectively. RZ is dedicated to the BS transmission toward both RSs and MSs, while AZ is dedicated to the reception of MSs from the BS or two RSs. Assuming each RS receives data for relaying in RZ at the current frame, it should be scheduled to transmit the data in AZ and empty its buffer at the next frame. In each subframe, the frequency domain consists of subchannels and the time domain consists of slots. A slot in a subchannel is the minimum frequency-time resource unit TDD relay frame structure for MCNs.
Additionally, for WMNs, the frequency spectrum is shared and randomly contended by all stations. The access scheme with the lowest overhead is optimal. However, for example, in this paper, a centrally controlled optimal resource allocation for OFDMA-based MCNs is our target.
To provide analytical performance evaluation, we make two assumptions for the remainder of this paper:
1. All users have a single type of data service and thus have the same QoS requirements.
2. All cells/sectors have the same channel conditions, traffic load, and distribution of users.
CHAPTER 5
5.0 SYSTEM STUDY:
5.1 FEASIBILITY STUDY
The feasibility of the project is analyzed in this phase and business proposal is put forth with a very general plan for the project and some cost estimates. During system analysis the feasibility study of the proposed system is to be carried out. This is to ensure that the proposed system is not a burden to the company. For feasibility analysis, some understanding of the major requirements for the system is essential.
Three key considerations involved in the feasibility analysis are
5.1.1 ECONOMICAL FEASIBILITY
This study is carried out to check the economic impact that the system will have on the organization. The amount of fund that the company can pour into the research and development of the system is limited. The expenditures must be justified. Thus the developed system as well within the budget and this was achieved because most of the technologies used are freely available. Only the customized products had to be purchased.
5.1.2 TECHNICAL FEASIBILITY
5.1.3 SOCIAL FEASIBILITY
The aspect of study is to check the level of acceptance of the system by the user. This includes the process of training the user to use the system efficiently. The user must not feel threatened by the system, instead must accept it as a necessity. The level of acceptance by the users solely depends on the methods that are employed to educate the user about the system and to make him familiar with it. His level of confidence must be raised so that he is also able to make some constructive criticism, which is welcomed, as he is the final user of the system.
Software system meets its requirements and user expectations and does not fail in an unacceptable manner. There are various types of test. Each test type addresses a specific testing requirement.
TYPES OF TESTS
5.2.1 UNIT TESTING
Unit testing involves the design of test cases that validate that the internal program logic is functioning properly, and that program inputs produce valid outputs. All decision branches and internal code flow should be validated. It is the testing of individual software units of the application .it is done after the completion of an individual unit before integration. This is a structural testing, that relies on knowledge of its construction and is invasive. Unit tests perform basic tests at component level and test a specific business process, application, and/or system configuration. Unit tests ensure that each unique path of a business process performs accurately to the documented specifications and contains clearly defined inputs and expected results.
5.2.2 INTEGRATION TESTING
Integration tests are designed to test integrated software components to determine if they actually run as one program. Testing is event driven and is more concerned with the basic outcome of screens or fields. Integration tests demonstrate that although the components were individually satisfaction, as shown by successfully unit testing, the combination of components is correct and consistent. Integration testing is specifically aimed at exposing the problems that arise from the combination of components.
5.2.3 FUNCTIONAL TEST
Functional tests provide systematic demonstrations that functions tested are available as
specified by the business and technical requirements, system documentation, and user manuals.
Functional testing is centered on the following items:
Valid Input : identified classes of valid input must be accepted.
Invalid Input : identified classes of invalid input must be rejected.
Functions : identified functions must be exercised.
Output : identified classes of application outputs must be exercised.
Systems/Procedures: interfacing systems or procedures must be invoked.
Organization and preparation of functional tests is focused on requirements, key functions, or special test cases. In addition, systematic coverage pertaining to identify Business process flows; data fields, predefined processes, and successive processes must be considered for testing. Before functional testing is complete, additional tests are identified and the effective value of current tests is determined.
5.2.4 SYSTEM TEST
System testing ensures that the entire integrated software system meets requirements. It tests a configuration to ensure known and predictable results. An example of system testing is the configuration oriented system integration test. System testing is based on process descriptions and flows, emphasizing pre-driven process links and integration points.
5.2.5 WHITE BOX TESTING
White Box Testing is a testing in which in which the software tester has knowledge of the inner workings, structure and language of the software, or at least its purpose. It is purpose. It is used to test areas that cannot be reached from a black box level.
5.2.6 BLACK BOX TESTING
Black Box Testing is testing the software without any knowledge of the inner workings, structure or language of the module being tested. Black box tests, as most other kinds of tests, must be written from a definitive source document, such as specification or requirements document, such as specification or requirements document. It is a testing in which the software under test is treated, as a black box .you cannot “see” into it. The test provides inputs and responds to outputs without considering how the software works.
5.3 UNIT TESTING:
Unit testing is usually conducted as part of a combined code and unit test phase of the software lifecycle, although it is not uncommon for coding and unit testing to be conducted as two distinct phases.
Test strategy and approach
Field testing will be performed manually and functional tests will be written in detail.
Test objectives
Features to be tested
Software integration testing is the incremental integration testing of two or more integrated software components on a single platform to produce failures caused by interface defects.
The task of the integration test is to check that components or software applications, e.g. components in a software system or – one step up – software applications at the company level – interact without error.
Test Results:
All the test cases mentioned above passed successfully. No defects encountered.
5.5 ACCEPTANCE TESTING
User Acceptance Testing is a critical phase of any project and requires significant participation by the end user. It also ensures that the system meets the functional requirements.
Test Results:
All the test cases mentioned above passed successfully. No defects encountered.
CHAPTER 6
6.0 SOFTWARE ENVIRONMENT
6.1 FEATURES OF .NET
Microsoft .NET is a set of Microsoft software technologies for rapidly building and integrating XML Web services, Microsoft Windows-based applications, and Web solutions. The .NET Framework is a language-neutral platform for writing programs that can easily and securely interoperate. There’s no language barrier with .NET: there are numerous languages available to the developer including Managed C++, C#, Visual Basic and Java Script.
The .NET framework provides the foundation for components to interact seamlessly, whether locally or remotely on different platforms. It standardizes common data types and communications protocols so that components created in different languages can easily interoperate.
“.NET” is also the collective name given to various software components built upon the .NET platform. These will be both products (Visual Studio.NET and Windows.NET Server, for instance) and services (like Passport, .NET My Services, and so on).
6.2 THE .NET FRAMEWORK
The .NET Framework has two main parts:
1. The Common Language Runtime (CLR).
2. A hierarchical set of class libraries.
The CLR is described as the “execution engine” of .NET. It provides the environment within which programs run. The most important features are
Managed Code
The code that targets .NET, and which contains certain extra Information – “metadata” – to describe itself. Whilst both managed and unmanaged code can run in the runtime, only managed code contains the information that allows the CLR to guarantee, for instance, safe execution and interoperability.
Managed Data
With Managed Code comes Managed Data. CLR provides memory allocation and Deal location facilities, and garbage collection. Some .NET languages use Managed Data by default, such as C#, Visual Basic.NET and JScript.NET, whereas others, namely C++, do not. Targeting CLR can, depending on the language you’re using, impose certain constraints on the features available. As with managed and unmanaged code, one can have both managed and unmanaged data in .NET applications – data that doesn’t get garbage collected but instead is looked after by unmanaged code.
Common Type System
The CLR uses something called the Common Type System (CTS) to strictly enforce type-safety. This ensures that all classes are compatible with each other, by describing types in a common way. CTS define how types work within the runtime, which enables types in one language to interoperate with types in another language, including cross-language exception handling. As well as ensuring that types are only used in appropriate ways, the runtime also ensures that code doesn’t attempt to access memory that hasn’t been allocated to it.
Common Language Specification
The CLR provides built-in support for language interoperability. To ensure that you can develop managed code that can be fully used by developers using any programming language, a set of language features and rules for using them called the Common Language Specification (CLS) has been defined. Components that follow these rules and expose only CLS features are considered CLS-compliant.
6.3 THE CLASS LIBRARY
.NET provides a single-rooted hierarchy of classes, containing over 7000 types. The root of the namespace is called System; this contains basic types like Byte, Double, Boolean, and String, as well as Object. All objects derive from System. Object. As well as objects, there are value types. Value types can be allocated on the stack, which can provide useful flexibility. There are also efficient means of converting value types to object types if and when necessary.
The set of classes is pretty comprehensive, providing collections, file, screen, and network I/O, threading, and so on, as well as XML and database connectivity.
The class library is subdivided into a number of sets (or namespaces), each providing distinct areas of functionality, with dependencies between the namespaces kept to a minimum.
6.4 LANGUAGES SUPPORTED BY .NET
The multi-language capability of the .NET Framework and Visual Studio .NET enables developers to use their existing programming skills to build all types of applications and XML Web services. The .NET framework supports new versions of Microsoft’s old favorites Visual Basic and C++ (as VB.NET and Managed C++), but there are also a number of new additions to the family.
Visual Basic .NET has been updated to include many new and improved language features that make it a powerful object-oriented programming language. These features include inheritance, interfaces, and overloading, among others. Visual Basic also now supports structured exception handling, custom attributes and also supports multi-threading.
Visual Basic .NET is also CLS compliant, which means that any CLS-compliant language can use the classes, objects, and components you create in Visual Basic .NET.
Managed Extensions for C++ and attributed programming are just some of the enhancements made to the C++ language. Managed Extensions simplify the task of migrating existing C++ applications to the new .NET Framework.
C# is Microsoft’s new language. It’s a C-style language that is essentially “C++ for Rapid Application Development”. Unlike other languages, its specification is just the grammar of the language. It has no standard library of its own, and instead has been designed with the intention of using the .NET libraries as its own.
Microsoft Visual J# .NET provides the easiest transition for Java-language developers into the world of XML Web Services and dramatically improves the interoperability of Java-language programs with existing software written in a variety of other programming languages.
Active State has created Visual Perl and Visual Python, which enable .NET-aware applications to be built in either Perl or Python. Both products can be integrated into the Visual Studio .NET environment. Visual Perl includes support for Active State’s Perl Dev Kit.
Other languages for which .NET compilers are available include
| ASP.NET XML WEB SERVICES | Windows Forms |
| Base Class Libraries | |
| Common Language Runtime | |
| Operating System |
Fig1 .Net Framework
C#.NET is also compliant with CLS (Common Language Specification) and supports structured exception handling. CLS is set of rules and constructs that are supported by the CLR (Common Language Runtime). CLR is the runtime environment provided by the .NET Framework; it manages the execution of the code and also makes the development process easier by providing services.
C#.NET is a CLS-compliant language. Any objects, classes, or components that created in C#.NET can be used in any other CLS-compliant language. In addition, we can use objects, classes, and components created in other CLS-compliant languages in C#.NET .The use of CLS ensures complete interoperability among applications, regardless of the languages used to create the application.
CONSTRUCTORS AND DESTRUCTORS:
Constructors are used to initialize objects, whereas destructors are used to destroy them. In other words, destructors are used to release the resources allocated to the object. In C#.NET the sub finalize procedure is available. The sub finalize procedure is used to complete the tasks that must be performed when an object is destroyed. The sub finalize procedure is called automatically when an object is destroyed. In addition, the sub finalize procedure can be called only from the class it belongs to or from derived classes.
GARBAGE COLLECTION
Garbage Collection is another new feature in C#.NET. The .NET Framework monitors allocated resources, such as objects and variables. In addition, the .NET Framework automatically releases memory for reuse by destroying objects that are no longer in use.
In C#.NET, the garbage collector checks for the objects that are not currently in use by applications. When the garbage collector comes across an object that is marked for garbage collection, it releases the memory occupied by the object.
OVERLOADING
Overloading is another feature in C#. Overloading enables us to define multiple procedures with the same name, where each procedure has a different set of arguments. Besides using overloading for procedures, we can use it for constructors and properties in a class.
MULTITHREADING:
C#.NET also supports multithreading. An application that supports multithreading can handle multiple tasks simultaneously, we can use multithreading to decrease the time taken by an application to respond to user interaction.
STRUCTURED EXCEPTION HANDLING
C#.NET supports structured handling, which enables us to detect and remove errors at runtime. In C#.NET, we need to use Try…Catch…Finally statements to create exception handlers. Using Try…Catch…Finally statements, we can create robust and effective exception handlers to improve the performance of our application.
6.5 THE .NET FRAMEWORK
The .NET Framework is a new computing platform that simplifies application development in the highly distributed environment of the Internet.
OBJECTIVES OF . NET FRAMEWORK
1. To provide a consistent object-oriented programming environment whether object codes is stored and executed locally on Internet-distributed, or executed remotely.
2. To provide a code-execution environment to minimizes software deployment and guarantees safe execution of code.
3. Eliminates the performance problems.
There are different types of application, such as Windows-based applications and Web-based applications.
6.6 FEATURES OF SQL-SERVE
The OLAP Services feature available in SQL Server version 7.0 is now called SQL Server 2000 Analysis Services. The term OLAP Services has been replaced with the term Analysis Services. Analysis Services also includes a new data mining component. The Repository component available in SQL Server version 7.0 is now called Microsoft SQL Server 2000 Meta Data Services. References to the component now use the term Meta Data Services. The term repository is used only in reference to the repository engine within Meta Data Services
SQL-SERVER database consist of six type of objects,
They are,
1. TABLE
2. QUERY
3. FORM
4. REPORT
5. MACRO
TABLE:
A database is a collection of data about a specific topic.
VIEWS OF TABLE:
We can work with a table in two types,
1. Design View
2. Datasheet View
Design View
To build or modify the structure of a table we work in the table design view. We can specify what kind of data will be hold.
Datasheet View
To add, edit or analyses the data itself we work in tables datasheet view mode.
QUERY:
A query is a question that has to be asked the data. Access gathers data that answers the question from one or more table. The data that make up the answer is either dynaset (if you edit it) or a snapshot (it cannot be edited).Each time we run query, we get latest information in the dynaset. Access either displays the dynaset or snapshot for us to view or perform an action on it, such as deleting or updating.
CHAPTER 8
8.0 CONCLUSION:
In this paper, we have carried out a quantitative study on an adaptive resource allocation scheme based on interference coordination and load balancing for multihop cellular networks. We also propose a novel frequency reuse scheme to mitigate interference and maintain high spectral efficiency, and present practical LB-based handover mechanisms which can evenly distribute the traffic load and guarantee users’ quality of service.
Simulations
demonstrate that our scheme not only meets the requirement on coverage
probability, but also improves the sector throughput and accommodates more
users. To the best of our knowledge, this is the first work to provide dynamic
resource allocation by jointly considering interference coordination and load
balancing for MCNs. We expect that our method will play a significant role in
network planning and resource allocation in the future MCNs.
CHAPTER 9
9.0 REFERENCES:
[1] M. Salem, A. Adinoyi, H. Yanikomeroglu, and D. Falconer, “Opportunities and Challenges in OFDMA-Based Cellular Relay Networks: A Radio Resource Management Perspective,” IEEE Trans. Vehicular Technology, vol. 59, no. 5, pp. 2496-2510, Jan. 2010.
[2] Y. Zhao, X. Fang, and Z. Zhao, “Interference Coordination in Compact Frequency Reuse for Multihop Cellular Networks,” IEICE Trans. Fundamentals of Electronics, Comm. and Computer Sciences, vol. E93-A, no. 11, pp. 2312-2319, Nov. 2010.
[3] Third Generation Partnership Project, “Technical Specification Group Radio Access Network; Physical Layer Aspects for Evolved Universal Terrestrial Radio Access (UTRA) (Release 7),” 3GPP Technical Report 25.814 v7.1.0, Sept. 2006.