Dual Mode Mobile Network Access Using Utility Functions-1

CHAPTER 1 Introduction : Integration of the IEEE 802.11 wireless LANs (WLANs) and 3G networks, such as Universal Mobile Telecommunication Service (UMTS), has been intensively studied recently due to their complementary characteristics. The 3GPP has been continuously evolving to support multimedia services which require high data rates in cellular networks. Nowadays, a UMTS network can support services with maximum data rate of 2Mbps while a 2.5G cellular network, such as General Packet Radio Service (GPRS), can only provide 100-200 kbps. UMTS networks are gaining popularities and being deployed globally in countries such as UK, Japan and USA. To further increase the data rate at the downlink side, High Speed Downlink Packet Access (HSDPA) was introduced by the 3GPP research community providing data rate up to 14Mbps. Deployment of HSDPA networks has been commercially launched, but network operators may be reluctant to completely replacing existing legacy networks which are fully functional as it would require an extremely high installation cost. Meanwhile, the commercial success of the IEEE 802.11 protocol makes the access point-based WLAN networks widely deployed in hot-spot areas such as offices, airports and coffee shops. The IEEE 802.11b can provide data rate up to 11Mb/s in 2.4 GHz. The IEEE 802.11a and IEEE 802.11g can provide up to 54 Mb/s in 5GHz and 2.4GHz bands, respectively. But WLANs have disadvantages of having small coverages. The coverage by an access point (AP) of a WLAN is up to several hundred meters in radius and a cell covered by a UMTS Node B is usually several kilometers in radius. Such complimentary characteristics of these two popular networks have stimulated research efforts to integrate UMTS and WLAN networks so that mobile stations can choose the network that has better network quality when they are covered by 1

both networks. The hardware requirement for integrating UMTS and WLAN networks is mainly to build dual-mode user equipment (UE) which has the capability of accessing either network. After such a dual-mode UE is available and software’s at each network’s operational components are updated, a ubiquitous wireless environment with high data rate enabled in hot spot areas can be set up. The integrated WLAN/UMTS systems, the access control problem arises to decide which network it should be admitted to and when it should switch from one network it should be admitted to and when it should switch from one network to the other through vertical handover. The decision can be made by a new software layer named as IP Switch layer which resides in the UE and keeps monitoring the situation of current cell. Once the traffic in one network becomes higher and the network efficiency gets impaired, the IP switch layer delivers the packets from the upper layer to the other network’s interface. In this paper, we propose a network access decision algorithm based on the utility-based access control framework. Utility function is a concept borrowed from economics and has been used for scheduling and allocating resources in wireless communication systems. In our proposed framework, admission control and vertical handover decisions are made through evaluating some utility functions implemented in UMTS’s Node B, RNC and WLAN’s AP. The utility functions are designed so that each network’s capacity is considered to achieve load balancing between UMTS and WLAN networks.

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1.1 EXISTING SYSTEM: When a mobile station is covered by both networks in the integrated WLAN/UMTS systems, the access control problem arises to decide which network it should be admitted to and when it should switch from one network to the other through vertical handover. The decision can be made by a new software layer named as IP Switch layer which resides in the UE and keeps monitoring the situation of current cell. Once the traffic in one network becomes higher and the network efficiency gets impaired, the IP switch layer delivers the packets from the upper layer to the other network’s interface.

PROPOSED SYSTEM: we propose a network access decision algorithm based on the utility-based access control framework. Utility function is a concept borrowed from economics and has been used for scheduling and allocating resources in wireless communication systems. In our proposed framework, admission control and vertical handover decisions are made through evaluating some utility functions implemented in UMTS's Node B, RNC, and WLAN's AP. The utility functions are designed so that each network's capacity is considered to achieve load balancing between UMTS and WLAN networks. We implemented a dual-mode UE in the NS-2 software.

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CHAPTER 2 UMTS: UMTS is a Third Generation (3G) wireless protocol that is part of the International Telecommunications Union’s IMT-2000 vision of a global family of 3G mobile communications systems. UMTS is expected to deliver low-cost, high-capacity mobile communications, offering data rates up to 2 Mbps. NS2 UMTS Specialized Model allows you to model UMTS networks to evaluate end-to-end service quality, throughput, drop rate, end-to-end delay, and delay jitter through the radio access network and core packet network. It can also be used to evaluate the feasibility of offering a mix of service classes given quality of service requirements. UMTS model features include: Based on WCDMA •

Support for 4 QoS classes: Background, Conversational, Interactive, Streaming

•

Support for UE, Repeater, Node B, RNC, SGSN, GGSN with ATM and IP Network connectivity

•

Dedicated (DCH) and Common / Shared Channels (RACH, FACH, DSCH)

•

Multiplexing of logical channels to transport channels

•

Acknowledged / Unacknowledged / Transparent RLC modes

•

Radio Access Bearer setup, release, negotiation, renegotiation, preemption

•

Open Source Admission Control

•

Outer loop power control

•

Hard / Soft / Softer handover

•

GTP Support up to RNC

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Universal Mobile Telecommunications System (UMTS) is one of the thirdgeneration (3G) mobile telecommunications technologies, which is also being developed into a 4G technology. Currently, the most common form of UMTS uses W-CDMA as the underlying air interface. UMTS and its use of W-CDMA is standardized by the 3GPP, and is the European answer to the ITU IMT-2000 requirements for 3G cellular radio systems. 2.1 FEATURES OF UMTS: UMTS, using W-CDMA, supports up to 21 Mbit/s data transfer rates in theory (with HSDPA), although at the moment users in deployed networks can expect a transfer rate of up to 384 kbit/s for R99 handsets, and 7.2 Mbit/s for HSDPA handsets in the downlink connection. This is still much greater than the 9.6 kbit/s of a single GSM errorcorrected circuit switched data channel or multiple 9.6 kbit/s channels in HSCSD (14.4 kbit/s for CDMAOne), and—in competition to other network technologies such as CDMA2000, PHS or WLAN---offers access to the World Wide Web and other data services on mobile devices. Precursors to 3G are 2G mobile telephony systems, such as GSM, IS-95, PDC, CDMA PHS and other 2g technologies deployed in different countries. In the case of GSM, there is an evolution path from 2G, to GPRS, also known as 2.5G. GPRS supports a much better data rate (up to a theoretical maximum of 140.8 kbit/s, though typical rates are closer to 56 kbit/s) and is packet switched). It is deployed in many places where GSM is used. E-GPRS, or EDGE, is a further evolution of GPRS and is based on more modern coding schemes. With EDGE the actual packet data rates can reach around 180 kbit/s (effective). EDGE systems are often referred as “2.75G Systems”.

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Since 2006, UMTS networks in many countries have been or are in the process of being upgraded with High Speed Downlink Packet Access (HSDPA), some things known as 3.5G. Currently, HSDPA enables downlink transfer speeds of up to 21 Mbit/s. Work is also progressing on improving the uplink transfer speed with the High-Speed Uplink Packet Access (HSUPA). Longer term, the 3GPP Long Term Evolution project plans to move UMTS to 4G speeds of 100 Mbit/s down and 50 Mbit/s up, using a next generation air interface technology based upon Orthogonal frequency-division multiplexing. The first national consumer UMTS networks launched in 2002 with a heavy emphasis on telco-provided mobile applications such as mobile TV and video calling. The high data speeds of UMTS are now most often utilized for Internet access: experience in Japan and elsewhere has shown that user demand for video calls is not high, and telco-provided audio/video content has declined in popularity in favour of highspeed access to the World Wide Web – either directly on a handset or connected to a computer via Wi-Fi, Bluetooth, Infrared or USB.

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CHAPTER 3 UMTS 3G Mobile Wireless Network Architecture: Universal Mobile Telecommunications System (UMTS), standardized by the 3GPP, is the 3G mobile communication technology successor to GSM and GPRS. UMTS combines the W-CDMA, TD-CDMA, or TD-SCDMA air interfaces, GSM’s Mobile Application Part (MAP) core, and the GSM family of speech codecs. W-CDMA is the most popular cellular mobile telephone variant of UMTS in use. UMTS, using W-CDMA, supports up to 14.0 Mbit/s data transfer rates in theory with High Speed Downlink Packet Access (HSDPA), although the performance in deployed networks could be much lower for both uplink and downlink connections. 3.1 RADIO ACCESS CORE NETWORK A major difference of UMTS compared to GSM is the air interface forming Generic Radio Access Network (GeRAN). It can be connected to various backbone networks like the Internet, ISDN, GSM or to a UMTS network. GeRAN includes the three lowest layers of OSI model. The network layer (OSI 3) protocols form the Radio Resource Management protocol (RRM). They manage the bearer channels between the mobile terminals and the fixed network including the handovers. The UMTS standard is an extension of existing networks based on the GSM and GPRS technologies. In UMTS release 1, a new radio access network UMTS terrestrial radio access network (UTRAN) is introduced. UTRAN, the UMTS radio access network (RAN), is connected via the Iu to the GSM Phase 2+ core network (CN). The Iu is the UTRAN interface between the radio network controller (RNC) and CN; the UTRAN 7

interface between RNC and the packet-switched domain of the CN (Iu-PS) is used for PS data and the UTRAN interface between RNC and the circuit-switched domain fo the CN (Iu-CS) is used for CS data. 3.2 UTRAN UTRAN is subdivided into individual radio network systems (RNSs), where each RNS is controlled by an RNC. The RNC is connected to a set of Node B elements, each of which can serve one or several cells. Two new network elements, namely RNC and Node B, are introduced in UTRAN. The RNC enables autonomous radio resource management (RRM) by UTRAN. It performs the same functions as the GSM BSC, providing central control for the RNS elements (RNS and Node Bs). Node B is the physical unit for radio transmission/reception with cells. Node B connects with the UE via the W-CDMA Uu radio interface and with the RNC via the Iub asynchronous transfer mode (ATM)-based interface. Node B is the ATM termination point.

Figure 1: UMTS-WLAN Interworking Architecture 8

UMTS Network Architecture: From the Radio Access to Core Network

•

Modeling UMTS Power Saving based on M/G/1 Queue with Vacations o We investigated the power saving mechanism of UMTS. UMTS DRX is exercised between the network and a mobile station (MS) to save the power of the MS. The DRX mechanism is controlled by two parameters: the inactivity timer threshold tI and the DRX cycle tD. Queueing analytic and simulation models were proposed to study the effects of tI and tD on output measures including the expected queue length, the expected packet waiting time, and the power saving factor.

9

•

Main achievements and outcomes o Research or technology outcomes 

To the best of our knowledge, our work is the first one to model UMTS power saving mechanism by using M/G/1 queue with vacations.

3.3 Wireless LAN (WLAN): A wireless LAN (WLAN) is a wireless local area network that links two or more computers or devices using spread-spectrum or OFDM modulation technology based to enable communication between devices in a limited area. This gives users the mobility to move around within a broad coverage area and still be connected to the network. 3.4 Benefits The popularity of wireless LANs is a testament primarily to their convenience, cost efficiency, and ease of integration with other networks and network components. The majority of computers sold to consumers today come pre-equipped with all necessary wireless LAN technology. Benefits of wireless LANs include:

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Convenience The wireless nature of such networks allows users to access network resources from nearly any convenient location within their primary networking environment (home or office). With the increasing saturation of laptop-style computers, this is particularly relevant. Mobility With the emergence of public wireless networks, users can access the internet even outside their normal work environment. Most chain coffee shops, for example, offer their customers a wireless connection to the internet at little or no cost. Productivity Users connected to a wireless network can maintain a nearly constant affiliation with their desired network as they move from place to place. For a business, this implies that an employee can potentially be more productive as his or her work can be accomplished from any convenient location. For example, a hospital or warehouse may implement Voice over WLAN applications that enable mobility and cost savings. Deployment Initial setup of an infrastructure-based wireless network requires little more than a single access point. Wired networks, on the other hand, have the additional cost and complexity of actual physical cables being run to numerous locations (which can even be impossible for hard-to-reach locations within a building).

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Expandability Wireless networks can serve a suddenly-increased number of clients with the existing equipment. In a wired network, additional clients would require additional wiring. Cost Wireless networking hardware is at worst a modest increase from wired counterparts. This potentially increased cost is almost always more than outweighed by the savings in cost and labor associated to running physical cables. Disadvantages Wireless LAN technology, while replete with the conveniences and advantages described above, has its share of downfalls. For a given networking situation, wireless LANs may not be desirable for a number of reasons. Most of these have to do with the inherent limitations of the technology. Security Wireless LAN transceivers are designed to serve computers throughout a structure with uninterrupted service using radio frequencies. Because of space and cost, the antennas typically present on wireless networking cards in the end computers are generally relatively poor. In order to properly receive signals using such limited antennas throughout even a modest area, the wireless LAN transceiver utilizes a fairly considerable amount of power. What this means is that not only can the wireless packets be intercepted by a nearby adversary's poorly-equipped computer, but more importantly, a user willing to spend a small amount of money on a good quality antenna can pick up

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packets at a remarkable distance; perhaps hundreds of times the radius as the typical user. In fact, there are even computer users dedicated to locating and sometimes even cracking into wireless networks, known as wardrivers. On a wired network, any adversary would first have to overcome the physical limitation of tapping into the actual wires, but this is not an issue with wireless packets. To combat this consideration, wireless networks users usually choose to utilize various encryption technologies available such as Wi-Fi Protected Access (WPA). Some of the older encryption methods, such as WEP are known to have weaknesses that a dedicated adversary can compromise. (See main article: Wireless security.) Range The typical range of a common 802.11g network with standard equipment is on the order of tens of meters. While sufficient for a typical home, it will be insufficient in a larger structure. To obtain additional range, repeaters or additional access points will have to be purchased. Costs for these items can add up quickly. Other technologies are in the development phase, however, which feature increased range, hoping to render this disadvantage irrelevant Reliability Like any radio frequency transmission, wireless networking signals are subject to a wide variety of interference, as well as complex propagation effects (such as multipath, or especially in this case Rician fading) that are beyond the control of the network administrator. One of the most insidious problems that can affect the stability and reliability of a wireless LAN is the microwave oven. In the case of typical networks, modulation is achieved by complicated forms of phase-shift keying (PSK) or quadrature 13

amplitude modulation (QAM), making interference and propagation effects all the more disturbing. As a result, important network resources such as servers are rarely connected wirelessly. Speed The speed on most wireless networks (typically 1-108 Mbit/s) is reasonably slow compared to the slowest common wired networks (100 Mbit/s up to several Gbit/s). There are also performance issues caused by TCP and its built-in congestion avoidance. For most users, however, this observation is irrelevant since the speed bottleneck is not in the wireless routing but rather in the outside network connectivity itself. For example, the maximum ADSL throughput (usually 8 Mbit/s or less) offered by telecommunications companies to general-purpose customers is already far slower than the slowest wireless network to which it is typically connected. That is to say, in most environments, a wireless network running at its slowest speed is still faster than the internet connection serving it in the first place. However, in specialized environments, higher throughput through a wired network might be necessary. Newer standards such as 802.11n are addressing this limitation and will support peak throughput in the range of 100-200 Mbit/s. 3.5 Types of Wireless LANs : Peer-to-peer Peer – to - Peer or a-hoc wireless LAN An ad-hoc network is a network where stations communicate only peer to peer (P2P). There is no base and no one gives permission to talk. This is accomplished using the Independence Basic Services Set (IBBS) 14

A peer-to-peer (P2P) network allows wireless devices to directly communicate with each other. Wireless devices within range of each other can discover and communicate directly without involving central access points. This method is typically used by two computers so that they can connect to each other to form a network. If a signal strength meter is used in this situation, it may not read the strength accurately and can be misleading , because it registers the strength of the strongest signal, which may be the closest computer. 802.11 specs define the physical layer (PHY) and MAC (Media Access Control) layers. However, unlike most other IEEE specs, 802.11 includes three alternative PHY standards: diffuse infrared operating at 1 Mbit/s in; frequency-hopping spread spectrum operating at 1 Mbit/s or 2 Mbit/s. A single 802.11 MAC standard is based on CSMA/CA(Carrier Sense Multiple Access with Collision Avoidence). The 802.11 speciation includes provisions designed to minimize collision. Because two mobile units may both be in range of a common access point, but not in range of each other. The 802.11 has two basic modes of operation; Ad hoc mode enables peer-to-peer transmission between mobile units. Infrastructure mode in which mobile units communicate through an access point that serves as a bridge to a wired network infrastructure is the more common wireless LAN application the one being covered. Since wireless communication used a more open medium for communication in comparison to wired LANs, the 802.11 designers also included shared-key encryption mechanism: Wired Equivalent Privacy (WEP) Wi-Fi Protected Access (WPA, WPA2), to secure wireless computer networks.

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Bridge : A bridge can be used to connect networks, typically of different types. A wireless Ethernet bridge allows the connection of devices on a wired Ethernet network to a wireless network. The bridge acts as the connection point to the Wireless LAN. A Wireless Distribution System is a system that enables the wireless interconnection of access points in an IEEE 802.11 network. It allows a wireless network to be expanded using multiple access points

without the need for wired back bone to

link them, as is traditionally required. The notable advantage of WDS over other solutions is that it preserves the MAC addresses of client packets across links between across links between access points. An access point can be either a main, relay or remote base station. A main base station is typically connected to the wired Ethernet. A relay base station relays data between remote base stations, wireless clients or other relay stations to either a main or another relay base station. A remote base station accepts connection from wireless clients and passes them to relay or main stations. Connection between “clients” are made using MAC address rather than by specifying IP assignments. All base stations in a Wireless Distribution System must be configured to use the same radio channel, and share WEP keys or WPA keys if they are used. They can be configured to different services set identifiers. WDS also requires that every base stations be configured to forward to others in the system.

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WDS may also be referred to as repeater mode it appears to bridge and accept wireless clients at the same time (unlike traditional bridging). It should be noted, however, that throughput in this method is haved for all clients connected wirelessly. When it is difficult to connect all of the access points in a network by wires, it is also possible to put up access points as repeaters. 3.6 Roaming: Roaming between Wireless Local Area Networks There are 2 definitions for wireless LAN roaming:

Internal Roaming (1): The Mobile Stations (MS) moves from one access point (AP) to another AP within a home network because the signal strength is too weak. An authentication of MS via 802.1 x (e.g. with PEAP). The billing of QoS is in the home network. A Mobile Station roaming from one access point to another often interrupts the flow of data between the Mobile Station and an application connected to the network. The Mobile Station, for instance, periodically monitors the presence of alternatives access points (ones that will provide a better connection). At some point, based upon proprietary mechanism, the Mobile Station decides to re-associate with an access point having a stronger wireless signal. The Mobile Station, however, may lose a connection with an access point before associating with another access point. In order to provide reliable connection with applications, the Mobile Stations must generally include software that provides session persistence.

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External Roaming (2): The MS (client) moves into a WLAN of another Wireless Internet Services Provider (WISP) and takes their services (Hotspot). The user can independently of his home network use another foreign network, if this is open for visitors. There must be special authentication and billing systems for mobile services in a foreign network. 3.7 Related work Several network architectures for integrating WLAN/UMTS systems have been proposed. The proposed architectures can be grouped into two categories based on the independence between the two networks [(14)], tight coupling and loose coupling. In the loose coupling architecture, two networks are integrated beyond the Core Network (CN) of UMTS. They are connected through gateways of the Internet. Communication between the two networks are realized through standard IP protocols and the mobility of mobile stations is managed through protocols such as Mobile IP. The loose coupling architecture enables the two networks deployed independently but results in longer delay for signaling and vertical handovers. In the tight coupling architecture, two networks are integrated at UMTS’s CN, which has lower delay for signaling and vertical handover but has higher implementation complexity. 3 GPP has been working on standardisation for integrating cellular and WLAN systems in which interworking architecture and interworking scenarios are desired. A policy based access control framework for cellular/WLAN systems was proposed where policies are designed to archive load balancing, but details of the proposed scheme such as performance analysis are not available.

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CHAPTER 4 SYSTEM MODEL Inspired by the Dual Mode Terminal (DMT) implemented a dual-mode UE (DMUE) which can switch between UMTS and WLAN networks. Our DMUE is different from the DMT in which our DMUE can be adopted in loose coupling interworking systems where the UMTS and WLAN networks are connected by a router, whereas DMT is only applicable in tight coupling interworking systems. The protocols in UMTS and WLAN are independent. Packets arriving at the router are routed according to the subnet address of each network. Once packets are delivered to the UMTS or WLAN network, communication protocols of the corresponding network are then applied. The main difference of UMTS and WLAN mobile stations is in the MAC and the physical layers. In the DMUE, we created a new software layer, called IP switch layer, below the IP layer and above UMTS’s GPRS Mobility Management (GMM) layer and WLAN’s Address Resolution Protocol (ARP) layer. In the protocol stack of the DMUE, a network access decision is made at the IP switch layer. Each DMUE has multiple pre-assigned IP addresses with different subnets, and one IP address is called the primary IP address, others are called the subordinate IP addresses. The primary IP address is the one and only one IP address which is recognizable to the layers above IP switch layer. All the IP addresses should be registered first such that each individual IP address has a unique MAC address. Otherwise, an invalid IP address can cause packets to be discarded during the packet transmission. Each AP of WLAN or Node B of UMTS has a unique IP subnet. When a DMUE is roaming close to a Node B or an AP which has an identical subnet as the DMUE’s, this Node B or AP becomes a connection candidate. When the IP switch

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layer receives a PDU from the upper layer, the primary IP address in the packet header is replaced by the IP address of a selected candidate at the IP switch layer according to some specific network selection algorithm. When the IP switch layer receives a PDU from the lower layer, the IP address is reinstated to the primary IP address. By this method, the network access decision is completely transparent to the layers above the IP switch layer. A network access decision can be made by either the DMUE itself or the server. If the decision is made by the server, another entity is needed to act as a Common Radio Resource Management (CRRM). Generally, a CRRM gathers the information on the load and average packet delay of each base station and finds a best solution for the system overall load balancing. Decisions are then broadcasted to all DMUEs through base stations. In this paper, our focus is on the first method, i.e., the network access decision is made by the DMUE. Instead of broadcasting network access decisions directly to DMUEs, each base station broadcasts “virtual prices” to the neighboring DMUEs. Since all DMUEs are independent entities, they may use different network access decision algorithms based on the “virtual price” to choose an appropriate network. In Figure 3, when a DMUE gets a “virtual price” packet from the lower layer, it will pass this “virtual price” to “get_price_info” processor to make a network access decision. 4.1 Utility function for the UMTS: In the UMTS networks, the admission control procedure is started when a new service is requested. The request includes traffic’s QoS requirement such as data rate, delay requirement, etc. After the UTRAN (RNC and Node B) of the UMTS network receives the request, it will decide whether to grant the request based on the network condition. The network condition is evaluated by the UTRAN through computing load 20

factors for uplink and downlink .In UMTS systems, load factors are always controlled to be below than a threshold, say max ç ( max ç < 1). In most UMTS systems, 0.75 is a value commonly used for both uplink and downlink threshold of max ç . In this paper, we assume the uplink and downlink load factors have the same value of max ç . When a service request comes, the UTRAN estimates the new resulting load factors of both uplink and downlink.

Utility function for the WLAN: A WLAN network has more bandwidth than a UMTS network does. A desirable scenario in the integrated WLAN/UMTS networks would be that in a hotspot area, i.e., covered by WLAN, most of the stations are connected to the WLAN to enjoy the high data rate of WLAN, while in the area outside hotspots, i.e., only covered by UMTS, static or mobile stations are connected to UMTS to enjoy the large coverage of UMTS. However, WLAN does not have explicit QoS control. When the WLAN is heavily loaded, some QoS metric such as delay cannot be guaranteed. Moreover, as pointed out in WLAN achieves less throughput when the network is saturated than that when the network is not saturated. As the traffic load (number of stations) increases, severe collisions occur, which results in that the stations can barely transmit a packet successfully. Thus, the WLAN network should be closely monitored such that the network is not overbusy. An indicator reflecting the WLANutilization adopted in the literature is busyness ratio which is defined as the ratio of the time that the network is sensed busy. So stations are admitted/handovered to a WLAN network only when its busyness ratio b R is less than a threshold Given the current busyness ratio b R and its

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upper bound th R , the utility function for WLAN indicating the available bandwidth to accommodate new stations . 4.2 Network access decision: Each AP of WLAN and Node-B of UMTS calculates its own utility function (either periodically or triggered by events). The computed utilities are then broadcasted. Once a station receives the utility from either UMTS or WLAN network, it will compare the received utility with the utility of the host network to decide whether to switch Network k. Notice that to avoid unnecessary oscillation, i.e., a station keeps switching back and forth between two networks, a variable, utility_gap, is introduced such that only when the utility of a candidate network is larger than the utility of host network by utility_gap, the station changes the network. Secondly, as the network utility is broadcasted, all stations will receive it almost at the same time as the transmission time in the media is negligible. Then, all the stations will try to switch to the network that has higher utility. As a result, the network that has higher utility before will be loaded very quickly (i.e., low utility) and the network that has lower utility before will be depleted (i.e., high utility), which leads the stations to switch the network again. To avoid this undesirable network trembling, each station keeps a random number stay T . Each station has to stay in a network for at least stay T seconds before switching to another network.

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CHAPTER 5 UTILITY FUNCTION ALGORITHM The algorithm is based on both UMTS and WLAN utility functions like current busy ratio, data packet size and current uplink and downlink load factors and bandwidth. The busy ratio of is associated by the above factors. The notations are Rb is the Busy Ratio and ηmax. When the WLAN is heavily loaded, some QoS metric such as delay cannot be guaranteed. Moreover, as pointed out in [11], WLAN achieves fewer throughputs when the network is saturated than that when the network is not saturated. As the traffic load (number of stations) increases, severe collisions occur, which results in that the stations can barely transmit a packet successfully. Thus, the WLAN network should be closely monitored such that the network is not overbusy. An indicator reflecting the WLAN utilization adopted in the literature is busyness ratio, which is defined as the ratio of the time that the network is sensed busy. NETWORK ACCESS DECISION Each AP of WLAN and Node-B of UMTS calculates its own utility function (either periodically or triggered by events). The computed utilities are then broadcasted. Once a station receives the utility from either UMTS or WLAN network, it will compare the received utility with the utility of the host network to decide whether to switch network.

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1. Algorithm NetworkAccessDecision () 2. { 3.

if the utility comes from UMTS then

4. 5.

new_utility = f UMTS ; else

6.

new_utility = f WLAN ;

7.

endif

8.

new_network_id = the id of the network where the new utility comes from;

9.

if current_network_id = new_network_id then

10. 11.

current_utility = new_utility; else

12.

if new_utility > current_utility + utility_gap then

13.

switch to the network with id being new_network_id;

14. 15.

endif endif

16. }

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CHAPTER 6 3G Radio Network Controller Third Generation (3G) is a generic name for technologies that support highquality voice, high-speed data and video in wireless cellular networks. In Europe, WCDMA/3G services are called the Universal Mobile Telephony System (UMTS). An overview of the UMTS wireless network UTRAN (Terrestrial Radio Access Network) is shown below. The UMTS Terrestrial Radio Access Network (UTRAN) includes the Radio Network Controller (RNC), the 3G Base stations (Node Bs) and the air interface (Tower) to the mobile equipment (ME). A brief description of the different network elements and interfaces in a UMTS network is provided in the following table:

3G Network Functions MSC

The Mobile Switching Center (MSC) switch, including the Visitor Location Register (VLR), is a switch that serves the Mobile Equipment (ME) in its

GMSC

current location for Circuit Switched (CS) services. The Gateway MSC (GMSC) switch serves the UMTS network at the point

MGW

where it is connected to the external CS network. The MSC and GMSC handle control Funtionality, but user data goes through the Media Gateway (MGW), which performs the actual switching for user data

SGSN

and network inter-working processing. The Serving GPRS Support Node (SGSN) covers functions similar to the MSC for packet data, including VLR type functionality 25

GGSN

The Gateway GPRS Support Node (GGSN) connects the Packet-Switched (PS)

Node B

core network to other networks such as the Internet. A 3G Base station (Node B) handles radio channels, including the

RNC

multiplexing/demultiplexing of user voice and data information. The Radio Network Controller (RNC) is responsible for controlling and managing the multiple base stations (Node Bs) including the utilization of radio network services.

6.1. RNC Node B The Radio Network Controller (RNC) is responsible for controlling and managing the multiple base stations (Node Bs). The RNC also performs user data processing to manage soft handoff and the utilization of radio network services. This processing requires significant packet handling and manipulation, as well as complex higher-level protocols. The density of the selector function is a major factor determining the capacity of an RNC. The rising cost of the infrastructure needed to provide sufficient capacity for advanced mobile Internet services is a key challenge facing cellular operators and other mobile telecommunications service providers. Wireless equipment manufacturers must be able to add more flexibility and processing power to line cards without inflating system cost or exceeding the power budget.

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Specific design challenges for RNC include: •

Increased application complexity to support evolving 3gpp standards

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Market demands for more data services, requiring modular and reusable hardware and software building blocks

•

Standardization requirements, such as Advanced TCATM, driven by reductions in CAPEX/OPEX and time-to-market

•

Move from feature-based to cost-driven systems cost per channel and MIPS per watt as the main selection criteria

27

6.2 Overview of GPRS and UMTS GPRS and UMTS are evolutions of the global system for mobile communication (GSM) networks. GSM is a digital cellular technology that is used worldwide, predominantly in Europe and Asia. GSM is the world’s leading standard in digital wireless communications. GPRS is a 2.5G mobile communications technology that enables mobile wireless service providers to offer their mobile subscribers packet-based data services over GSM networks. Common applications of GPRS include the following: Internet access, intranet/corporate access, instant messaging, and multimedia messaging. GPRS was standardized by the European Telecommunications Standards Institute (ETSI), but today is standardized by the Third Generation Partnership Program (3GPP). UMTS is a 3G mobile communications technology that provides wideband code division multiple access (CDMA) radio technology. The CDMA technology offers higher throughput, real-time services, and end-to-end quality of service (QoS), and delivers pictures, graphics, video communications, and other multimedia information as well as voice and data to mobile wireless subscribers. UMTS is standardized by the 3GPP. *Gateway GPRS support node (GGSN)—a gateway that provides mobile cell phone users access to a public Data network (PDN) or specified private IP networks. The GGSN function is implemented via Cisco IOS software on the Cisco 7200 series router or on the Cisco Multi-Processor WAN Application Module (MWAM) installed in a Catalyst 6500 series switch or Cisco 7600 series Internet router. Cisco IOS GGSN Release 4.0 and later provides both the 2.5G GPRS and 3G UMTS GGSN functions. 28

*Serving GPRS support node (SGSN)—connects the radio access network (RAN) to the GPRS/UMTS core and tunnels user sessions to the GGSN. The SGSN sends data to and receives data from mobile stations, and maintains information about the location of a mobile station (MS). The SGSN communicates directly with the MS and the GGSN. SGSN support is available from Cisco partners or other vendors. 6.3 Benefits The 2.5G GPRS technology provides the following benefits: •

Enables the use of a packet-based air interface over the existing circuit-switched GSM network, which allows greater efficiency in the radio spectrum because the radio bandwidth is used only when packets are sent or received.

•

Supports minimal upgrades to the existing GSM network infrastructure for network service providers who want to add GPRS services on top of GSM, which is currently widely deployed

•

Supports enhanced data rates in comparison to the traditional circuit-switched GSM data service

•

Supports larger message lengths than Short Message Service (SMS)

•

Supports a wide range of access to data networks and services, including VPN/Internet service provider (ISP) corporate site access and Wireless Application Protocol (WAP).

In addition to the above, the 3G UMTS technology includes the following: •

Enhanced data rates of approximately

•

144 kbps—Satellite and rural outdoor

•

384 kbps—Urban outdoor 29

•

2048 kbps—Indoor and low-range outdoor

•

Supports connection-oriented Radio Access Bearers with specified Qos enabling endto-end Qos

6.4 GGSN Interworking GGSN Release 5.0 and later is a fully-compliant 2.5G and 3.5G GGSN that provides the following features: •

Release 99 (R99), Release 98 (R98) and Release 97 (R97)support and compliance

•

GTPv0 and GTPv1 messaging

•

IP Packet Data Protocol (PDP) and PPP PDP types

•

Cisco Express Forwarding (CEF) switching for GTPv0 and GTPv1, and for IP and PPP PDP types

•

Support of secondary PDP contexts for GTPv1 (up to 11)

•

Virtual APN

•

VRF support per APN

•

Multiple APNs per VRF

•

VPN support

•

Generic routing encapsulation (GRE) tunneling

•

Layer 2 Tunneling Protocol (L2TP) extension for PPP PDP type

•

PPP Regeneration for IP PDP type

•

802.1Q virtual LANs (VLANs)

•

Security features 30

•

Duplicate IP address protection

•

PLMN range checking

•

Blocking of Foreign Mobiles

•

Anti-spoofing

•

Mobile-to-mobile redirection

•

Quality of service (QoS)

•

Support of UMTS classes and interworking with differentiated services (DiffServ)

•

Delay QoS

•

Canonical Qos

•

GPRS QoS(R97/R98) conversion to UMTS QoS (R99) and the reverse

•

Call Admission Control

•

Per-PDP policing

•

Dynamic address allocation

•

External DHCP server

•

External RADIUS server

•

Local pools

•

Anonymous access

•

RADIUS authentication and accounting

•

Accounting

•

Wait accounting

•

Per-PDP accounting

31

•

Authentication and accounting using RADIUS server groups mapped to APNs

•

3GPP vendor-specific attributes (VSAs) for IP PDP type

•

Transparent mode accounting

•

Class attribute

•

Interim updates

•

Session idle timer

•

Packet of Disconnect (PoD)

•

Dynamic Echo Timer

•

GGSN interworking between 2.5G and 3G SGSNs with registration authority (RA) update from

•

2.5G to 2.5G SGSN

•

2.5G to 3G SGSN

•

3G to 3G SGSN

•

3G to 2.5G SGSN

•

Charging

•

Time trigger

•

Charging profiles

•

Tertiary charging gateway

•

Switchback to primary charging gateway

•

Maintenance mode

•

Multiple trusted PLMN IDs

32

•

GGSN-IOS SLB messaging

•

Session timeout

33

CHAPTER 7 ABOUT NS2: Ns2 – Network Simulator Tool Ns2 is a simulation tool built by South-California University and regenerated by ISI and some others. The NS2 was built using three languages. TCL script, C++, C. Here, TCL used for control, C++ for data and most of the header files were created by C. In NS2 Scripting, we can simulate a wired, wireless and Satellite networks using ns script. And the ns scripted files are saved with the extension of *.tcl. (TCL: Tool Command Language). Ns Goals – 1. It supports the application for network research and education eg: Protocol design, protocol comparison and traffic studies etc. 2. Provide a collaborative environment with freely distributed, open source and allow easy comparison of similar protocols, Increase confidence in results. Possible to get multiple levels of detail in on simulator. 3. It supports the FreeBSD, Linux, Solaris, Windows and Mac. Ns Functionalities: It supports the wired/wireless network simulations.

34

Wire world : •

Router – DV, LS, PIM-SM

•

Transportation – TCP, UDP

•

Traffic Sources web, FTP, Telnet, CBR, Stochastic

•

Queuing disciplines – drop-tail, RED, FQ, SFQ,DRR

•

Qos – Intserv and Diffserv

In wired Network, we can create connection between two nodes through TCP as well as UDP protocols and generating traffic using protocols like FTP ( File Transfer Protocol), Telnet ( Tele Network), CBR ( Constant bit Rate) And we can specify the queuing discipline also, the no of queuing disciplines are in as2. they are drop-tail, RED, FQ,SFQ , DRR. Wireless World: •

Using Adhoc routing and Mobile IP.

•

Directed diffusion, sensor-MAC.

In Wireless Network also , we can create connection between two nodes through TCP as well as UDP protocols and generating traffic using protocols like FTP ( File Transfer Protocol), Telnet (Tele Network), CBR(Constant Bit Rate). And we need to import some Wireless Supported classes for creating wireless network.

35

Ns2 provides various utilities like Tracing and visualization. The visualization achieve by NAM (Network AniMator) and NAM Editor provides GUI interface to generate Ns scripts (Normally we use TCL script). The Trace Analysis can achieve by XGraph. 7.1 Ns programming : 

Create the event scheduler



Turn on tracing



Create network



Setup routing



Insert errors



Create transport connection



Create traffic



Transmit application-level data

Creating Event Scheduler 

Create event scheduler Set ns [ new Simulator]



Schedule events $ns at <event> <event>: any legitimate ns/tcl commands $ns at 5.0 “finish”



Start scheduler 36

$ns run

37

Tracing and Monitoring I o Packet tracing: 

On all links : $ns trace-all [open out.tr.w]



On one specific link: $ns trace-queue $n0 $n1$tr

<Event> <size> -- <src> <seq> +

1

0

2

cbr

210

-------- 0 0.0 3.1 0 0

-

1

0

2

cbr

210

-------- 0 0.0 3.1 0 0

R 1.00234 0 2 cbr 210

--------- 0 0.0 3.1 0 0

•

We have new trace format



Evet tracing (support TCP right now)

•

Record “event” in trace file : $ns eventtrace-all

•

E 2.267203 0 4 TCP slow_start 0 210 1

Tracing and Monitoring II •

Queue monitor set qmon [$ns monitor-queue $n0 $n1 $q_f $sample_interval]

•

Get statistics for a queue $qmon set pdrops_

 Record to trace file as an optional 29.000000000000142 0 1 0.0 0.0 4 4 0 1160 1160 0



Flow monitor set fmon [$ns_makeflowmon Fid] $ns_attach-fmon $slink $fmon

38

$fmon set pdrops_

Tracing and Monitoring III

 Visualize trace in nam $ns namtrace-all [open test.nam w] $ns namtrace-queue $n0 $n1

 Variable tracing in nam Agent/TCP set nam_tracevar_true $tcp tracevar srrt_ $tcp tracevar cwnd_

 Monitor agent variables in nam $ns add-agent-trace $tcp $tcp $ns monitor-agent-trace $tcp $srm0 tracevar cwnd_ $ns delete-agent-trace $stp 7.2 Creating Network Nodes set n0 [$ns node] set n1 [ $ns node] Links and queuing $ns $n0 $n1 <delay> < queue_type>

 :duplex-link, simplex-link

39

 : DropTail, RED, CBQ, FQ, SFQ, DRR, diffserv RED queues

Creating Network: LAN $ns make-lan <node_list> <delay> <mac_type> :LL : Queue/Drop Tail, <mac_type>: MAC/802_3 : Channel Setup Routing

 Unicast $ns rtproto type>: Static, Session, DV, Cost, Multi-path

 Multicast $ns multicast (right after [new Simulator]) $ns mrtproto : CrtMcast, DM,ST,BST

 Other types of routing supported: source routing , hierarchical routing Creating Connection and Traffic

 UDP set udp [new Agent/UDP] set null [ new Agent/Null] 40

$ns attach-aget $n0 $udp $ns attach-agent $n1 $null $ns connect $udp $null

 CBR set src [ new Application/Traffic/CBR]

 Exponential or Pareto on-off set src { new Application/Traffic/Exponential] set src [ new Application /Traffic/pareto]

Creating Connection and Traffic II

 TCP set tcp [ newAgent/TCP] set tcpink [new Agent/TCPSink] $ns attach-agent $n0 $tcp $ns attach-agent $n1 $tcpsink $ns onnect $tcp $tcpsink

 FTP set ftp [ new Application/FTP] $ftp attach-agent $tcp

 Telnet set telnet [ new Application/Telnet] 41

$telnet attach-agent $tcp

7.3 ns→nam Interface

 Color  Node manipulation  Link manipulation  Topology layout  Protocol state nam Interface : color



Color mapping $ns color 40 red $ns color 41 blue



Color ↔ flow id association $tcp0 set fid_40 ;# red packets $tcp 1 set fid_41 ;# blue packets

nam interface : Nodes

 color $node color red

 Shape (can’t be changed after sim starts) 42

$node shape box ;#circle,box,hexagon

 Marks (concentric “shapes”) $ns at 1.0 “$n0 add-mark m0 blue box” $ns at 2.0 “$n0 delete-mark m0”

 Label (single string) $ns at 1.1 “$n0 label \”web cache 0\”” nam Interface : Links

 Color $ns duplex-link-op $n0 $n1 color “green”

 Label $ns duplex-link-op $n0 $n1 label “abced”

 Dynamics (automatically handled) $ns rtmodel Deterministic {2.0 0.9 0.1} $n0 $n1

 Asymmetric links not allowed nam Interface: Topo Layout

 “Manual “ layout : specify everything $ns duplex-link-op $n(0) $n(1) orient right $ns duplex-link-op $n(1) $n(2) orient right $ns duplex-link-op $n(2) $n(3) orient right $ns duplex-link-op $n(3) $n(4) orient 60 deg Annotation and Animation Rate 43

 Add textual explanation to your simulation $ns at 3.5 “$ns trace-annotate \”packet drop\””

 set animation rate $ns 0.0 “$ns set-animation-rate 0.1 ms”

44

CHAPTER 8 Simulation Results In the simulation scenario, we create a UMTS network with one Node B and a WLAN with one AP DMUEs in the intersection coverage area of the two networks. Each DMUE has two IP address, one is in the UMTS subnet 192.168.6.0, the other is in the WLAN subnet 192.168.5.0. An application of UDP video uploading from each DMUE to the server is applied. Each video frame has size 17280 bytes, and a constant inter-arrival time 4 seconds. All DMUEs enter the network between 0 and 200 seconds. The total simulation time is 3600 seconds. In Case 1, each UE randomly select either UMTS or WLAN and initiates a connection. Admission to the UMTS cell is done based on the load factor as implemented in OPNET UMTS module. There is no specific admission control in WLAN, and any user can try to share the bandwidth as specified in the 802.11 protocol. No switching between the two networks is performed. In Case 2, each DMUE randomly select either UMTS or WLAN and initiates a connection as in Case 1. However, in this case, switching,i.e., vertical handovers are performed based on the utility values as discussed. As a result, some of the DMUEs initially connected to the UMTS network switch to the WLAN network. The DMUE’s uplink transmit load in Case 2 is displayed in Figure 4. We notice that vertical handovers are done from UMTS to WLAN network since the utility value of the latter is larger than that of the former,i.e., the WLAN has a larger remaining

45

bandwidth. From the simulation result shown in Figure 5, we see that the overall throughput measured at the server with utility based approach in Case 2 is much larger than Case 1. At the end of the simulation, in Case 1, all five UEs still reside in the WLAN network but only one UE resides in the UMTS network, other four are all dropped because UMTS has a relatively small capacity, and it is not able to accommodate all five UEs. In Case 2, nine DMUEs reside in the WLAN network, and none resides in the UMTS network. Among the previous five DMUEs assigned to the UMTS network, four successfully switch to the WLAN network and the other one was not admitted by the UMTS network, four successfully switch to the WLAN network and the other one was not admitted by the UMTS network in the initiation due to insufficient capacity. One may argue that the WLAN-first algorithm, i.e., try to connect to WLAN if available, should work even better. Whenthe total capacity of UMTS cells sharing the coverage area with the WLAN is relatively small as in our simulation scenario, it may be true. But in reality, multiple UMTS cells have overlapping area and the total capacity can be close to the capacity of WLAN. In this case, it is not obvious whether the WLAN-first algorithm performs well. Finally, in Case 1 of our simulation, either of the networks is selected with 59% resulting in very poor performance due to the unbalanced capacities of the two networks. Without having capacity information, 50% of random selection seems to be a reasonable choice by any UE.

46

47

48

WLAN / UMTS Interlink

49

CHAPTER 9 CONCLUSION In this paper, we designed a dual-mode mobile station module DMUE which works in the WLAN/UMTS interworking system. Based on the DMUE design, we proposed a utility-based access control frame work for integrated WLAN/UMTS system. In our frame work, the UMTS’s UTRAN and the WLAN’s AP measure their respective network conditions and reflect network conditions numerically by dynamically calculating utilities. Each network’s utility is broadcasted to all DMUEs. DMUE’s network access decision is made by comparing the received utilities. The simulation results using NS-2 show that our proposed scheme performs significantly better than the reference one. Our developed models are not yet available NS-2 community, but will be made available after further analysis is performed.

50

CHAPTER 10 FEATURE IMPLEMENTATION Overview: Demand for wireless LAN hardware has experienced phenomenal growth during the past several years, evolving quickly from novelty into necessity. As a measure of this expansion, WLAN chipset shipments in 2005 surpassed the 100-million-unit mark, a more than tenfold increase from 2001 shipments of less than 10 million units. Thus far, demand has been driven primarily by users connecting notebook computers to networks at work and to the Internet at home as well as at coffee shops, airports, hotels, and other mobile gathering places. As a result, Wi-Fi® technology is most commonly found in notebook computers and Internet access devices such as routers and DSL or cable modems. In fact, more than 90 percent of all notebook computers now ship with built-in WLAN. he growing pervasiveness of Wi-Fi is helping to extend the technology beyond the PC and into consumer electronics applications like Internet telephony, music streaming, gaming, and even photo viewing and in-home video transmission. Personal video recorders and other A/V storage appliances that collect content in one spot for enjoyment around the home are accelerating this trend.

51

Wi-Fi® Standards Comparison: The first WLAN standard to become accepted in the market was 802.11b, which specifies encoding techniques that provide for raw data rates up to 11 Mbps using a modulation technique called Complementary Code Keying, or CCK, and also supports Direct-Sequence Spread Spectrum, or DSSS, from the original 802.11 specification. The 802.11a standard, defined at about the same time as 802.11b, uses a more efficient transmission method called Orthogonal Frequency Division Multiplexing, or OFDM. OFDM, as implemented in 802.11a, enabled raw data rates up to 54 Mbps. Despite its higher data rates, 802.11a never caught on as the successor to 802.11b because it resides on an incompatible radio frequency band: 5 GHz versus 2.4 GHz for 802.11b. Note: All of the WLAN standards provide for multiple transmission options, so that the network can drop to lower (albeit easier to maintain) data rates as environmental interference challenges communications. In the most favorable circumstances, 802.11a and 802.11b support data rates up to 54 Mbps and 11 Mbps respectively.) In June 2003, the IEEE ratified 802.11g, which applied OFDM modulation to the 2.4-GHz band. This combined the best of both worlds: raw data rates up to 54 Mbps on the same radio frequency as the already popular 802.11b. WLAN hardware built around 802.11g was quickly embraced by consumers and businesses seeking higher bandwidth. In fact, consumers were so eager for a higher-performing alternative to 802.11b that they began buying WLAN client and access-point hardware nearly a year before the standard was finalized.

52

Today, the vast majority of computer network hardware shipping supports 802.11g. Increasingly, as technology improves and it becomes easier and less costly tosupport both 2.4 GHz and 5 GHz in the same chipset, dual-band hardware is becoming more commonplace. Much of the WLAN client hardware available today, in fact, supports both 802.11a and 802.11g. A similar scenario to the draft 802.11g phenomenon is now unfolding with 802.11n. The industry came to a substantive agreement with regard to the features to be included in the high-speed 802.11n standard in early 2006. And though it will likely be 2007 before the standard is ratified, the specification is stable enough for draft-n Wi-Fi cards and routers to already be making their way to store shelves.

IP BASED CORE NETWORK

53

Table 1. Major Components of Draft 802.11n Feature Better OFDM SpaceDivision Multiplexing

Diversity

MIMO Power Save 40 MHz Channels

Aggregation Reduced Inter-frame Spacing (RIFS) Greenfield Mode

Specification Status

Definition

Supports wider bandwidth & higher code rate to bring Mandatory maximum data rate to 65 mbps Improves performance by parsing data into multiple streams transmitted through multiple antennas Exploits the existence of multiple antennas to improve range and reliability. Typically employed when the number of antennas on the receiving end is higher than the number of streams being transmitted. Limits power consumption penalty of MIMO by utilizing multiple antennas only on as-needed basis

Optional for up to four spatial streams Optional for up to four antennas

Required

Effectively doubles data rates by doubling channel width from 20 Optional MHz to 40 MHz Improves efficiency by allowing transmission bursts of multiple Required data packets between overhead communication One of several draft-n features designed to improve efficiency. Provides Required a shorter delay between OFDM transmissions than in 802.11a or g. Improves efficiency by eliminating Currently support for 802.11a/b/g devices in optional an all draft-n network

54

Table 2. Primary IEEE 802.11 Specifications 802.11a

802.11b

802.11g

802.11n

Standard Approved

July 1999

July 1999

June 2003

Not yet ratified

Maximum Data Rate

54 Mbps

11 Mbps

54 Mbps

600 Mbps

Modulation

OFDM

DSSS or CCK

DSSS or CCK or OFDM

DSSS or CCK or OFDM

RF Band

5 GHz

2.4 GHz

2.4 GHz

2.4 GHz or 5 GHz

Number of Spatial Streams

1

1

1

1, 2, 3, or 4

Channel Width

20 MHz

20 MHz

20 MHz

20 MHz or 40 MHz

55

REFERENCES: 1. OPNET network simulator, http://www.opnet.com/. 2. IEEE 802.11 WG, Part 11:Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specification, Standard, IEEE, Aug.1999. 3. IEEE 802.11b WG, Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specification: High-speed Physical Layer Extension in the 2.4 GHz Band, IEEE, Sep. 1999. 4. IEEE 802.11a WG, Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specification: High-speed Physical Layer Extension in the 5 GHz Band, IEEE, Sep. 1999. 5. IEEE 802.11g, Further Higher-Speed Physical Layer Extension in the 2.4 GHz Band, 2003. 6. 3GPP. 3rd Generation partnership Project; Technical Specification Group Radio Access Network; RRC Protocol Specification for Release 1999. Techinical Specification 3G TS 25.331 version 3.5.0 (2000- 12),2000. 7. 3GPP TK 22.934, Feasibility study on 3GPP system to wireless local area network (WLAN) interworking, v. I .0.0, Release 6, Feb. 2002.

56

8. 3GPP, Group Services and System Aspects; 3GPP Systems to Wireless Local Area Network (WLAN) Interworking; System Description (Release 6), TS 23.234, v. 6.2.0, Sept. 2004. 9. W. Song, W. Zhuang, and Y. Cheng, Load Balancing for Cellular/WLAN Intergrated Networks, IEEE Network, issue 1,pp.27- 33, 2007. 10. Giuseppe Bianchi, Performance Analysis of the IEEE 802.11 Distributed Coordination Function, IEEE Journal on Selected Areas in Communications, vol. 18, no.3, March 2000. 11. H. Zhai, X. Chen, and Y. Fang, How Well Can the IEEE 802.11 Wireless LAN Support Quality of Service, IEEE Trans. Wireless Commun, vol. 4, no. 6, Nov. 2005, pp. 3084C94. 12. R. Agrawal, V. Subramanian and R. Berry, Joint Scheduling and Resource Allocation in CDMA Systems, Proc. of 2nd Workshop on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks WiOpt 04), Cambridge, UK, March 24-26, 2004. 13. J. Huang, V. Subramanian, R. Agrawal, and R. Berry, Downlink Scheduling and Resource Allocation for OFDM Systems, Conference on Information Sciences and Systems (CISS), Princeton University, NJ, USA, March 2006. 14. M. Buddhikot, G. Chandranmenon, S. Han, Y. W. Lee, S. Miller and L. Salgarelli, Integration of 802.11 and Third-Generation Wireless Data Networks, Proc. IEEE INFOCOM, Apr. 2003.

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15. F. Siddiqui,S. Zeadally and S. Fowler, A Novel Architecture for Roaming between 3G and Wireless LANs, 1st International Conference on Multimedia Services Access Networks, MSAN’05, 2005. 16. H. Holma, A. Toskala, WCDMA for UMTS Radio Access for Third Generation Mobile Communications, John Wiley & Sons, 3rd edition, 2004.

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TABLE OF CONTENTS CHAPTER

TITLE

NO.

PAGE NO iii iv vii viii 1 3 4

1 1.1 2

ABSTRACT ACKNOWLEDGEMENT LIST OF FIGURES AND TABLES LIST OF ABBREVATIONS INTRODUCTION Existing System and Proposed System UMTS

2.1 3

Features 3G WIRELESS NETWORK ARCHITECTURE

5 7

3.1

Radio Access Core Network

7

3.2

UTRN

8

3.3

Wireless LAN

10

3.4

Benefits

10

3.5

Types of Wireless LAN

14

3.6

Roaming

17

3.7 4

Related Works SYSTEM MODEL

18 19

4.1

Utility function for UMTS/WLAN

20

4.2 5

Network Access Decision UTILITY FUNCTION ALGORITHM

22 23

6

3G RADIO NETWORK CONTROLLER

25

6.1

RNC Node B

26

6.2

Overview of GPRS and UMTS

28

6.3

Benefits

29

6.4

GGSN Inter Working

30

59

7

ABOUT NS2

33

7.1

NS2 Programming

35

7.2

Creating Network

37

7.3

Nam Interface

40

8 9 10

SIMULATION RESULTS CONCLUSIONS FUTURE WORK REFERENCES

42 47 48 53

60

LIST OF FIGURES AND TABLES

FIGURE NO. 1 2 3 4 5 6 1 2 3

CAPTION UMTS-WLAN Interworking Architecture

UMTS Network Architecture UTRN Roaming Scinario IP based Core Network Routing of Mobile calls to CS or PSTN (3GPP) TABLES 3G Network Functions Major Components of Draft 802.11n Primary IEEE 802.11 Specifications

PAGE NO 8 9 10 27 50 52 25 51 52

61

LIST OF ABBREVATIONS: RNC

Radio Network Controller

RNS

Radio Network Subsystem

RRC

Radio Resources Control (3GTS 25.331)

SGSN

Serving GPRS Support Node

SLR

Source Local Reference (SCCP)

DLR

Destination Local Reference (SCCP)

SCCP

Signaling Connection Control Part (ITU-T Q.710 – Q714)

SM

Session Management

SMS

Short Message Services

SRNC

Serving Radio Network Controller

SSCOP

Service Specific Connection Oriented Protocol (ITU-T Q.2110)

TBF

Temporary Block Flow

TCP

Transmission Control Protocol

TLLI

Temporary Logical Link Identifier

UDP

User Datagram Protocol

UMTS

Universal Mobile Telecommunication System for the time beyond the year 2000

UTRAN

UMTS Terrestrial Radio Access Network

VCI

Virtual Channel Identifier

VPI

Virtual Path Identifier

W-CDMA

Wideband Code Division Multiple Access

62

63