Enhanced Radio Access Technologies for Next Generation Mobile Communication phần 2 pdf

OVERVIEW OF MOBILE COMMUNICATION 23

This distance can be increased to 100 meters by amplifying the power to 20dBm.

The Bluetooth radio system is optimized for mobility.

The name Bluetooth was born from the 10th century king of Denmark, King

Harold Blaatand (whose surname is sometimes written as Bluetooh), who engaged

in diplomacy which led warring parties to negotiate with each other. The inventors

of the Bluetooth technology thought this a fitting name for their technology which

allowed different devices to talk to each other.

The Bluetooth specification was first developed by Ericsson (now Sony Ericsson),

and was later formalized by the Bluetooth Special Interest Group (SIG). The SIG

was formally announced on May 20, 1999. It was established by Sony Ericsson,

IBM, Intel, Toshiba and Nokia, and later joined by many other companies as

Associate or Adopter members.

Bluetooth technology already plays a part in the rising Voice over IP (VOIP)

scene, with Bluetooth headsets being used as wireless extensions to the PC audio

system. As VOIP becomes more popular, and more suitable for general home or

office users than wired phone lines, Bluetooth may be used in Cordless handsets,

with a base station connected to the Internet link.

In March 2006, the Bluetooth Special Interest Group (SIG) announced its intent

to work with UWB (ultra-wideband) manufacturers to develop a next-generation

Bluetooth technology using UWB technology and delivering UWB speeds. This

will enable Bluetooth technology to be used to deliver high speed network data

exchange rates required for wireless VOIP, music and video applications.

The IEEE 802.15.3 High Rate Task Group (TG3) for WPANs is chartered to

draft and publish a new standard for high-rate (20Mbit/s or greater) WPANs.

Besides a high data rate, the new standard will provide for low power, low cost

solutions addressing the needs of portable consumer digital imaging and multimedia

applications. Another member of 802.15 family is the IEEE 802.15 High Rate

Alternative PHY Task Group (TG3a) or 802.15.3a is working to define a project

to provide a higher speed Ultra-wideband (UWB) PHY enhancement amendment

to 802.15.3 for applications which involve imaging and multimedia.

Ultra-Wideband (UWB) is a recently allocated unlicensed spectrum

(3.1–10.6 GHz) that provides an efficient use of scarce radio bandwidth while

enabling both high data rate personal-area network wireless connectivity as well as

long-range, low data rate applications. UWB was previously defined as an impulse

radio, but the industry now views it as an available bandwidth set with an emissions

limit that enables coexistence without harmful interference.

Due to its extremely short range, UWB is limited to the same sort of devices that

Bluetooth is used for. The main advantage to using Ultra-wideband as opposed to

Bluetooth is, as the name implies, bandwidth speed. Excepting any interference, a

UWB device could theoretically achieve transfer speeds of up to 1 Gbps (today’s

Bluetooth devices have a theoretical limit of 3Mbps). The ranges of applica￾tions for these kinds of speeds are staggering even given the range limitations

of UWB.

24 CHAPTER 1

Figure 7. UWB applications example

As Figure 7 indicates, UWB is a potential market includes a broad spectrum of

products and applications. One typical scenario is promising wireless data connec￾tivity between a host and associated peripherals such as keyboards, mouse, printer,

scanner, and so on. A UWB link functions as a ‘cable replacement’ with transfer

data rate requirements that range from 1000 Kbps for wireless mouse to 100 Mbps

for rapid file sharing or download of images/graphic files. Additional driver appli￾cations relate to streaming of digital media content between consumer electronics

appliances, such as digital TVs, VCRs, CD/DVD players, MP3 players and so on.

In summary UWB is seen as having potential for applications that to date have not

been fulfilled by other wireless short-range technologies currently available, such

as, 802.11 LANs or Bluetooth PANs.

One of the technologies fully utilizing the advantages of UWB is the Wireless

USB (WUSB). WUSB is a new wireless extension to USB intended to combine the

speed and security of wired technology with the ease-of-use of wireless technology.

WUSB is based on ultra wideband wireless technology defined by WiMedia (IEEE

802.15.3a), which operates in the range of 3.1–10.6 GHz.

Wireless USB supports the 480 Mbps data rate over a distance of two meters.

If the speed is lowered to 110 Mbps, UWB will go a longer distance (up to 10

meters). WUSB supports so-called dual-role devices, which in addition to being a

WUSB client device, can function as a host with limited capabilities. For example,

a digital camera could act as a client when connected to a computer, and as a host

when transferring pictures directly to a printer.

WUSB will be used in devices that are now connected via regular USB cables,

such as game controllers, printers, scanners, digital cameras, MP3 players, hard

disks and flash drives, but it is also suitable for transferring parallel video streams.

4th and last member of IEEE 802.15 family is the IEEE 802.15.4 was chartered

to investigate a low data rate solution with multi-month to multi-year battery

life and very low complexity. This standard specifies operation in the unlicensed

2.4 GHz, 915 MHz and 868 MHz ISM bands. The raw, over-the-air data rate is

OVERVIEW OF MOBILE COMMUNICATION 25

250 Kbps per channel in the 2.4 GHz band, 40 Kbps per channel in the 915 MHz

band, and 20 Kbps in the 868 MHz band. Transmission range is between 10 and

75 meters.

ZigBee is the most succeed technology based on 802.15.4 standard. ZigBee’s

current focus is to define a general-purpose, inexpensive, self-organizing, mesh

network that can be used for industrial control, embedded sensing, medical data

collection, smoke and intruder warning, building automation, interactive toys, smart

badges, remote controls, and home automation, etc. (Figure 8). The resulting

network will use very small amounts of power so individual devices might run for

a year or two using the originally installed battery.

We summarize the IEEE 802.15 based standards major parameters in Table 3.

4.3 WiBro/Mobile WiMax (IEEE 802.16e)

In February 2002, Korean government allocated 100 MHz bandwidth of 2.3GHz

spectrum band for WiBro (Wireless Broadband) system. WiBro allows subscribers

to use high-speed Internet more cheaply and more widely, even when moving at

speeds of about 60 km (37 miles) per hour. WiBro base stations will offer an

aggregate data throughput of 30 to 50 Mbps and cover a radius of 1–5 km allowing

for the use of portable Internet usage within the range of a base station. From testing

during the APEC Summit in Pusan in late 2005, the actual range and bandwidth

were quite a bit lower than these numbers. The technology will also offer Quality

of Service. The inclusion of QoS allows for WiBro to stream video content and

other loss-sensitive data in a reliable manner. The WiBro system was developed as

a regional and potentially international alternative to 3.5G systems, which delivers

Wireless Control that

Simply Work

ZigBee

security

HVAC

lighting control

access control

patient

monitoring

fitness

monitoring

asset mgt

process

control

environmental

energy mgt

TV

VCR

DVD/CD

remote

security

HVAC

lighting control

access control

lawn & garden irrigation

BUILDING

AUTOMATION

PERSONAL

HEALTH CARE

INDUSTRIAL

CONTROL

CONSUMER

ELECTRONICS

PC &

PERIPHERALS

RESIDENTIAL /

LIGHT

COMMERCIAL

CONTROL

mouse

keyboard

joystick

Figure 8. ZigBee applications example