4G Wireless Networks
4G Wireless Networks
Implementation and challenges Implementation and challenges What is 4G?
What is 4G? 4G
4G is is the the foufourtrth h gengeneraeratiotion n wirwireleeless ss netnetworwork k comcommunmunicaicatiotions ns tectechnolhnology ogy StaStandandard.rd. When implemented, users of 4G devices will have the ability to access to application When implemented, users of 4G devices will have the ability to access to application ranging from basic voice communication to seamless real time streaming video.
ranging from basic voice communication to seamless real time streaming video. What technologies comprise 4G?
What technologies comprise 4G?
Unlike previous standards such as 3G (third generation), 4G is based entirely on packet Unlike previous standards such as 3G (third generation), 4G is based entirely on packet switched networks. In addition, all 4G networks will be digital and will provide higher switched networks. In addition, all 4G networks will be digital and will provide higher bandwidths of up to 100 Mbps. 4G is actually a collection of previous standards as bandwidths of up to 100 Mbps. 4G is actually a collection of previous standards as
oppo
oppose se to to an an ententireirely ly new new stastandandardsrds. . StaStandandards rds sucsuch h as as 3G 3G and Bluetand Bluetootooth h wilwill l bebe incorporated in to the 4G standards.
incorporated in to the 4G standards. Why do we need 4G?
Why do we need 4G?
One may wonder why 4G is needed when 3G has not yet been fully implemented. Firstly One may wonder why 4G is needed when 3G has not yet been fully implemented. Firstly 3G’s maximum data transfer rate of 384 Kbps is much lower than 2 Mbps. The most 3G’s maximum data transfer rate of 384 Kbps is much lower than 2 Mbps. The most influential reason for the fall of the 3G networks and rise of 4G networks is the cost influential reason for the fall of the 3G networks and rise of 4G networks is the cost related to the creation of 3G networks. In Europe and Asia, several companies have related to the creation of 3G networks. In Europe and Asia, several companies have invested huge money on licensing and implementation of 3G Networks.
invested huge money on licensing and implementation of 3G Networks.
With its use of existing technologies and communication standards, 4G present a With its use of existing technologies and communication standards, 4G present a com
comparparabably ly ininexexpepensnsivive e ststanandadardrd. . 4G 4G wiwill ll ututililizize e momost st of of ththe e exiexiststining g wiwirerelelessss com
commumuninicacatition on ininfrfrasastrtrucuctuturere. . In In adaddiditition, on, ththerere e wiwill ll be be leless ss lilicecensnsining g cocoststs s inin comparison to 3G since 4G will utilize frequencies
comparison to 3G since 4G will utilize frequencies deemed to be in the deemed to be in the public domain.public domain. What are the specifications of 4G?
What are the specifications of 4G?
One may ask how 4G can provide a 10 times increase in data transfer over 3G. This One may ask how 4G can provide a 10 times increase in data transfer over 3G. This speed can be achieved through Orthogonal Frequency Division Multiplexing (OFDM). speed can be achieved through Orthogonal Frequency Division Multiplexing (OFDM). OFDM can not only transfer data at speed of more than 100 Mbps, but it can also OFDM can not only transfer data at speed of more than 100 Mbps, but it can also eliminate interference that impairs high speed signals.
eliminate interference that impairs high speed signals. What are the potential applications of 4G?
What are the potential applications of 4G?
With its high bandwidth and incorporation of several standards, 4G will provide for a With its high bandwidth and incorporation of several standards, 4G will provide for a vast number of presently non-existent applications for mobile devices. Some believe that vast number of presently non-existent applications for mobile devices. Some believe that it will be possible for users to purchase groceries, watch movies, and open their garages it will be possible for users to purchase groceries, watch movies, and open their garages all with one single mobile device. Experts have stated that 4G devices will differ from all with one single mobile device. Experts have stated that 4G devices will differ from prese
present day nt day mobilmobile e devicedevices in s in that there will be that there will be fewer navigatfewer navigation menus. [4] ion menus. [4] InsteInstead thead the device
devices s will interwill interpret the environment of the pret the environment of the device and base device and base actioactions on ns on the users input.the users input. In addition, 4G
will likely succeed where 3G failed and provide a seamless network for users who travel and require uninterrupted voice/data connections.
Comparing Key Parameters of 4G with 3G
3G (including 2.5G,
sub3G) 4G
Major Requirement Driving Architecture
Predominantly voice driven - data was always add on
Converged data and voice over IP
Network Architecture Wide area cell-based
Hybrid - Integration of Wireless LAN (WiFi, Bluetooth) and wide area Speeds 384 Kbps to 2 Mbps 20 to 100 Mbps in mobile
mode Frequency Band Dependent on country or
continent (1800-2400 MHz)
Higher frequency bands (2-8 GHz)
Bandwidth 5-20 MHz 100 MHz (or more) Switching Design
Basis Circuit and Packet
All digital with packetized voice
Access
Technologies W-CDMA, 1xRTT, Edge
OFDM and MC-CDMA (Multi Carrier CDMA)
Forward Error
Correction Convolution rate 1/2, 1/3
Concatenated coding scheme
Component Design Optimized antenna design, multi-band adapters
Smarter Antennas, software multilane and wideband
radios IP A number of air link
protocols, including IP 5.0 All IP (IP6.0)
Applications
Wireless users can be categorized into generalized segments. Users can be segmented in many ways. We are considering segmenting users in to the following categories: Gender, age, Internet usage, income brackets and mobile professional.
The Gender segment refers to new female users, versus traditional male users. These users are typically medium-income individuals. The types of applications being developed for this segment are social and entertainment applications such as instant Messaging and chatting. Being developed for this segment are messaging applications such as mobile faxing, e-mailing, and instant messaging? To augment solid applications, providers are also developing subscriber equipment to allow for roaming on disparate,
worldwide
The Age segment is composed of the youth market—generally individuals 18 years old or younger. Typically these users do not pay for their own service—their parents or guardians do. The types of applications being developed for this segment are social and entertainment applications such as music services.
The Internet Usage segment is composed of individuals that typically spend longer than average (i.e., more than about 32 minutes per session1) browsing the Internet.
Typical users in this segment are technology focused. The types of applications being developed for this segment are information applications such as personalized news services and streaming news feeds (i.e., delivered with audio, video, text, or any combination of the three). These users are especially difficult for providers to satisfy because they are accustomed to the Internet model of billing (i.e., essentially unlimited
usage for a small, Fixed fee).
The Income Bracket user segment is composed of middle-aged, value-conscious individuals. The types of applications being developed for this segment are information Services such as up-to-the-minute, personalized stock tickers. These users are also generally safety oriented; therefore, regular, reliable voice and data communications are paramount.
The Mobile Professional segment refers to users who rely on wireless devices to conduct day-to-day business. This segment includes professionals who travel on a regular basis. These users are generally very important to service providers because they often
spend more to obtain the services they require. The types of applications being developed for this segment are messaging applications such as mobile faxing, e-mailing, and instant messaging. To augment solid applications, providers are also developing subscriber equipment to allow for roaming on disparate, worldwide wireless networks using a single Communications device (worldwide interoperability). Establish a single profile that will be associated with the user whether in his/her home coverage area or roaming on other
systems.
Access Technology
The move towards what is being coined fourth generation (4G) wireless is complicated by the fact that a single 3G standard upon which to build does not exist. However, most
industry experts agree that the future of wireless is one in which voice, video, multimedia and broadband data services traveling across multiple wireless air interfaces are meshed into one seamless network. 4G Wireless networks will be characterized by the following: 1. Seamless network of multiple air interfaces and protocols
2. Improved spectral efficiency 3. IP Based
Several technologies based on multi -carrier modulation (MCM) have come to the forefront in order to achieve the above characteristics. We shall examine one such technology known as Orthogonal Frequency Division Multiplexing (OFDM). But the fact that OFDM is just one of many competing technologies highlights the need for reconfigurable and flexible software defined radio systems as a development platform. Here we will present architecture for a software development platform by first looking at the challenges of designing an OFDM -based system.
OFDM, orthogonal frequency division multiplexing, is a telecommunications technology that is the foundation of most next-generation, or 4G wireless Internet services for high speed data transmissions at comparable rates to fixed DSL services. OFDM transmits multiple signals simultaneously over a single wireless system.
This successful implementation of the OFDM waveform is the first step in Military SDR Technologies plan to implement the complete IEEE 802.16 family of wireless data applications, also known as WiMax, a higher performing version of WiFi. Emerging as the predominate technology for providing cost-effective, high-speed wireless Internet solutions, WiMax capabilities compare to traditional land based DSL services in terms of speed and cost, with the added capability of wireless mobility. WiMax-based services will be capable of delivering high quality voice, video and multimedia content over an Internet-based connection.
Orthogonal Frequency Division Multiplexing
OFDM is a communications technique that divides a communications channel into a number of equally spaced frequency tones (bands). OFDM is a form of multi-carrier modulation (MCM) where a sub-carrier within each frequency band is modulated to carry a portion of the user information. A communications data stream is effectively split into N parallel low bandwidth modulated data streams (Figure 1). Each sub-carrier overlaps, but they are all orthogonal to each other, such that they do not interfere with one another.
Each of the sub -carriers has a low symbol rate. But the combination of sub-carriers carrying information in parallel allows for high data rates. The other advantage of a low symbol rate is that inter-symbol interference (ISI) can be reduced dramatically since the symbol time represents a very small proportion of the typical multipath delay.
The transmitter stage of an OFDM transceiver takes data from an IP network, converts, and encodes it into a serial stream before modulation. The OFDM signal is generated using an Inverse Fast Fourier Transform (IFFT) into an IF analog signal which is then sent to the RF transceiver. The receiver stage of the transceiver simply reverses the process.
OFDM provides a particularly robust air interface that is resistant to the effects of multi-path delays while maintaining spectral efficiency. However, designers of OFDM and other MCM-based systems have been forced to deal with a host of challenges.
Basic OFDM Transmitter and Receiver
Backbone Networks
Convergence
Infrastructure link to the last mile
Flow control at access points/network edges Packet routing
Native-mode ATM, TCP/IP, mobile IP
Access: - Access Technology is one of the concern means what type of access network we should use which should cost effective, enhance data rate, and provide best quality of service. There are many name which could count CDMA, MCM, OFDM etc. but no one are gives best result according to requirements. But we can prefer OFDM, which discussed earlier. There are many advantages over CDMA and other Access technologies.
Handoff : - users can roam in heterogeneous networks, so Handoff delay is one of
the issues when user moves from one network to another network. During the handoff process, the user may experience a significant drop in QoS that will affect the performance of both upper-layer protocols and applications. Deploying a priority-based algorithm and using location-aware adaptive applications can
reduce both handoff delay and QoS variability. When there is a potential for considerable variation between senders’ and receivers’ device capabilities, deploying a receiver-specific filter in part of the network close to the source can effectively reduce the amount of traffic and processing, perhaps satisfying other users’ The delay will be the less in intranetwork, but delay can be problematic in internet work handoff because off authentication procedures that require messages exchange.
Location Coordination
Resource coordination to add new users Support for quality of service
Wireless securities and authentication Network failure and backup
Pricing and billing
A device capable of automatically switching between networks. 4G Network Architecture
The number of access networks in public, private business and home areas is increasing. To save both users and services from having to deal with many different access technologies, authentication strategies, and network peculiarities, these details should be hidden from them. On the other hand, the characteristics of the particular access network being used do matter. End users for example want to be able to use a specific network based on certain selection criteria like speed and cost. Service providers will need access
to specific network characteristics to be able to enhance their services, and may have certain requirements such as minimum delay guarantees. For the end user this means that in most circumstances he will not be aware of his services using different access networks simultaneously. This involves concepts like seamless roaming and the Virtual Home Environment (VHE). Another aspect is that the user needs to control the usage of the available networks, especially when this usage comes with a price. This involves a (potentially complex) decision making process which may be guided by policy management tools, with support from both end user devices and the networks. Another kind of integration is that of public, private and home networks. This has not received much attention yet, at least not to the extent as expected to be needed for next generation networks.
Business model of 4G Network
The current model assumes there are relationships between the end user, the service provider, and the network operator. In the 4G worlds, the number of access networks and therefore the number of network operators will increase rapidly. Especially the construction of many so-called “hotspots”, urban areas with Wireless LAN coverage, will cause this. Both the end user and the service provider do not want to be bothered with the
peculiarities of these networks, i.e. end users still want to use the services offered by service providers irrespective of the network they are connected to. This asks for a service centric approach where the end user, the service provider and network operator are loosely coupled through a Service Support role,
Two main responsibilities of Service Support are service aggregation and network integration Service aggregation (SA) enables ubiquitous service provisioning to end users, whereas network integration (NI) ensures that this can be realized regardless of the network the end user is connected to. The end user benefits from being able to access his/her subscribed services anywhere and anytime.
End users Identities and services
Third party service providers provide end user services. These service providers have established a legal relationship or Service Level Agreement (SLA) with one or more service aggregators. The services can benefit not only from a large customer base, but could also adapt their services and applications based on information from the network provided via the aggregators. It is envisaged that the user’s location can be obtained from
the network integrator (and therefore from access network) to deploy location-based services. The concept of user identity plays an important role in integrated service delivery. This ranges from authentication and access control to services, to accounting and billing; to be able to charge the correct end user for using his value-added context- based services.
Service Aggregator
The role of service aggregator (SA) is twofold. On the one hand the SA acts as an intermediary between a end user/subscriber and multiple services (the service offering of the SA). On the other hand, for Service Provider the SA acts as an intermediary to multiple different network integrators, such that services do not need to be concerned with issues eliminating the need for like determining on which network a subscriber is currently located active. In this model, end users explicitly subscribe to the SA. The SA manages these subscriptions and also takes care of billing; based on accounting information received from services, network integrators, and the SA itself. In this way the SA not only provides single sign-on, but a more general single point of contact.
Network Integration
The network integration (NI) enables end users to seamlessly roam across heterogeneous networks and their administrative domains. To support the seamless ness aspect is essential for this functionality. The NI provides the basic network management functionality and provides an abstraction of the underlying networks. This provides the illusion of one virtual network towards upper service layers and services, and also such as network integration specific aspects to end-users. For example, it provides transparent and integrated authentication such that end users are not required to re-login every time the access network changes. For services, NI takes care of connectivity – being able to reach the end user terminal. This involves network addressing issues and technologies such as Mobile IP.
Challenges
Submitted by
Santosh Kumar (200101183) Chinmay Chandan (200101152)
