Seamless means getting over barriers of different wireless standards and bands. So future mobile devices will be capable of supporting multiple wireless standards, and operate in a multimode, multiband fashion.
When there is a video message addressed to the mobile user, no matter where the user is located or what kind of terminal is being used, the message will be sent to the user correctly. When the user moves from his home network to a visiting network, his agents will migrate to the new network.
The 4G wireless communication system can be integrated with the Internet protocol (IP) backbone network to provide quality-of-service (QoS) support for multimedia applications. It will support dynamic scheduling, link adaptation and frequency selection as well as full roaming capabilities. 4G will also mean mobile telephony at a data rate of 100 Mbps globally (between any two points in the world) and 1 Gbps locally.
Towards broadband and wireless ubiquity
According to NTT-DoCoMo, a leading Japanese wireless company, the current data download speed for the i-Mode mobile Internet service is 9.6 kbps theoretically, although in practice the rates tend to be slower. 3G rates are expected to reach speeds 200 times that, while 4G will yield further increases, reaching 20 to 40 Mbps. 4G services would allow data transfer speeds of up to 20 MB/s for uplinks and 100 MB/s for downlinks-up to 260 times faster than popular 3G services, which allow for downlinks at 384 kB/s.
4G industry initiatives
The Wireless World Research Forum, consisting of Alcatel, Ericsson, Nokia and Siemens, has begun research on 4G. NTT DoCoMo has started conceptual design of the 4G network on paper and, along with Siemens, is conducting indoor tests with various radio conditions as preparation for future field tests to develop a 4G global standard in coordination with the International Telecommunication Union Radio-communication Sector.
In Japan, the telecommunications council of the Ministry of Internal Affairs and Communications is overseeing efforts to develop technologies for 4G commercial services by 2010. Verizon Wireless, a large service provider, is also likely to conduct trials of 4G applications.
Developments in India - The Indian government has established the Centre of Excellence in Wireless Technology (CEWT) in collaboration with IIT Madras to work on 4G wireless communications. India, as also China, may directly jump to 4G by the end of this decade.
4G architecture
The conceptual 4G system by DoCoMo is very different from the present 2.5G architecture as it has cells for outdoors, indoors and inside moving vehicles. Outdoor cells cover a wide area and allow data transfer at high bitrates for fast-moving terminals. Indoors, we will find separate access points.
Cells will be created within moving vehicles (like buses and trains) and served by a mobile router having wireless functions. Signals will be relayed through this router instead of the terminals individually communicating with the base station, Shadows and electronic interferences cause dead spots areas within the coverage of a wireless network in which transmission falls off. A multihop connection, which is effective in expanding the cell size, is being investigated as a way to overcome dead spots. Smart antennae can also help prevent dead spots resulting from multipath propagation.
Radio access
4G-radio access equipment will employ the variable-spreading-factor spread orthogonal frequency division multiplexing (OFDM) radio access method and multiple-input multiple-output (MIMO) multiplexing techniques. They will also use a new signal-detection algorithm to achieve 1Gbps peak data transmission with an l00 MHz downlink.
Smart antennae, OFDM, software-defined radio and mesh networking will be the building blocks of the 4G infrastructures. In fact, cell sites in the 4G world will eventually reside in the handset and towers will become as ubiquitous as handsets that will be on all the time.
Smart antennae
A smart antenna combines several antenna elements with a signal-processing capability to optimise its transmission and reception patterns automatically. Each antenna element sees each propagation path differently.
The smart antenna transmitters can encode independent streams of data onto different paths, thereby increasing the data rate, or they can encode data redundantly onto paths that fade independently to protect the receiver from calamitous signal fades. This leads to an increase in the signal quality through a more focused transmission and also enhances the capacity through frequency reuse. This increased capacity will translate to higher data rates for a given number of users or more users for a given data rate per user.
Another feature of smart antennae is that they dont need manual placement. They can electronically adapt to the environment by looking for pilot tones that the transmitted signal is known to have. Smart antennae can also separate signals from multiple users who are separated by distance but use the same radio channel with a technique called space-division multiple access.
Watchful path beyond 3G
4G wireless networks will bring in some major changes. We will see more and more battery-driven devices in use; sensors integrated into communication networks and use of new frequency bands with the release of the bandwidth. Cooperation across terminals and sub-networks and features such as reconfigurability, adaptivity, programmability and flexibility of access schemes, services and terminal devices will also be seen.
Low-cost mobile devices will access content conveniently and seamlessly, interacting with users in a multisensory manner. Devices customised for disabled people will be commonplace. The targeted data rates will be 50 to 100 Mbps.
There will be a shift from wide-range radio communications to short-range radio communications. Pervasive broadband wireless networking will encompass personal area networks (PANs), Which use Bluetooth, ZigBee and ultra-wide band (UWB) technologies, sensor networks as well as other advanced applications and services like radio-frequency identification (RFID) and mesh networking. Some technologies that will facilitate transition from 3G to 4G are:
1.ZigBee
ZigBee is a new wireless standard based on IEEEs 802.15.4 specification that could serve as a lower-cost alternative for wireless sensing and control. It allows small devices to quickly transmit small amounts of data such as temperature readings for thermostats and on/off requests for light switches or other remote monitoring and control needs. ZigBee devices can transmit information beyond 20 meters and run for years on inexpensive primary batteries.
ZigBee finds applications in professional installation kits for lighting control, heating, ventilation, air-conditioning and security. It is also well suited to building automation, industrial, medical, and residential control and monitoring applications.
2.UWB
UWB is a short-range wireless RF signal that can be used to relay data from a host device to other devices in the immediate area. A signal is UWB if its bandwidth is greater than 0.25 x carrier frequency. It works for devices 10 meters apart, helping to create a wire-free home or office. For example, all the components of a home entertainment centre can be connected without using wires.
UWB technology can transmit data between consumer electronics, PC peripherals and mobile devices at very high speeds while consuming little power. Its not a complete communication standard like Bluetooth.
3.WiBro
The WiBro technology, short for Wireless Broadband, is based on the 802.16e standard. It offers mobility, wide-area services and global standardisation for wireless broadband applications. With WiBro, users can wirelessly receive data applications and multimedia content, at speeds up to 121 kmph (75 miles per hour), while travelling across large geographic areas.
The applications of WiBro are diverse, including m-commerce, mobile trading, entertainment (for real-time streaming and broadcasting), 3-D gaming, interactive news and distance education. It can also be for information flow to networked homes - the deepest recesses of a country.
4.Wireless system discovery
To use 4G services; devices should be able to dynamically select the wireless system. This process is complicated in a 4G network because of its heterogeneous nature. One solution is to use software radio devices that can scan all the available networks. After scanning, these devices will load the required software and reconfigure themselves for the selected network. As shown in the figure, the software can be downloaded from such media as a PC server, smart card or memory card, or over the air. Operators will also enjoy simplified network management.
The vision - when we get there
E-mail - 4G wireless networks are expected to sweep the cell phone users off their feet, and make all our lives less complicated. With abundant services and media-rich broadband that will be 20 times faster than DSL, 4G networks will make even the common e-mail facility more interactive than it already is.
Sending e-mail could turn into a multimedia affair in a 4G world. Mobile users will have a multimedia inbox, and receive mail attachments in the form of high-resolution images, audio and video clips. The user can reply by recording an audio message, snapping a photo or shooting a video, and sending it right back, using just the mobile.
Health monitoring
4G could result in an increase in remote health monitoring of patients, as faster, real-time communication enables better two-way transmission of vital medical data.
Personal mobility and presence
4G will offer personalised communications to the mass market regardless of location, network and terminal used. High bandwidth and global capabilities of 4G could bring some useful applications for consumers and businesses. One could be a system that gives mobile users a virtual presence for example, always-on connections that keep people involved in business activities regardless of whether they are on-site or off. Personal mobility concentrates on the movement of users instead of users terminals, and involves provision of personal communications and personalised operating environments.
Tracking
The virtual presence system would also be able to track the exact whereabouts of individuals in case they need to be contacted. This capability might be used for law enforcement (checking whether the prisoners are where they are supposed to be) and tracking of packages and cargo shipments more precisely. For example, a large company will get to know not only that a package has arrived but also exactly whose desk it is sitting on at any given time using the network.
Networking and global roaming
4G will allow any mobile device run different wireless technologies automatically, and maintain connections seamlessly, using smart software. The software will also be capable of choosing the best connection available according to the users intentions. 4G will deliver not only enhanced multimedia and smooth streaming video but also universal access and portability across all types of devices.
4G will connect the entire globe and be operable from practically anywhere on the earth. It would allow for more complex voice-over-IP services, more media-rich messaging services and more native support for local area networking (such as 802.11 technology) on handsets.
Theres time
Analysts say it will take five to ten years before anything resembling 4G gets widespread penetration and acceptance. Carriers are not inclined to invest heavily in 4G infrastructures until demand for 3G picks up.
Mainstream consumer applications making use of 4G are at least a decade away. As we drive toward 4G, expect to see an evolution from fixed broadband to mobile broadband, more intelligent digital homes, converged broadband services, and personalised, convenient and seamless secured services.
4G will bring true human-like interaction with wearable, and maybe disposable, devices. Terminals will encompass speech, hearing, sight and other human senses, as well as environmental data pertinent to the application, making the user permanently connected to both the cyber-world as well as the real world. The services will provide effortless access to other people and devices around the 4G network and us will be designed for the highest possible integrity and security.
In fact, 4G can be best described as MAGIC (a short for Mobile multimedia, Anytime anywhere. Global mobility support, Integrated wireless solution and Customised personal service). The 4G era, beginning 2012, might just be as magical as we dream it!
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