Motivation And Implementation Of Wireless Gigabit Technology

Published Date: 02 Nov 2017

INTRODUCTION:

Due to high demand for digital Multimedia content to be available and be on demand to users has created a new problem under wireless communication .The Current commercial product can provide limited wireless transmission under standard applications .Wireless docking and display as well as network access need advanced standard rather than current Wi-Fi technology because they require much high data transmission .This has given rise to new Wireless Gigabit communication under WiGig Alliance[1] - consortium unified under a specification for wireless communication which is designed to drive a new ecosystem for interoperable products .WiGig alliance will provide a way by which many devices will access network at Gigabit speeds per second .60GHz band which is being deployed by WiGig alliance will facilitate new era of wireless access as well as be forefront of emerging standard in near future as per IEEE new 802.11ad amendment. Development of medium access MAC , physical PHY and several protocol layers PAL layers in to specification will provide extremely high data rates .The main objective in this paper will be to address the specification put forward by WiGig in accordance to new 802.11ad standard as it will supersede 802.11n standard currently in use today . Then in next section we investigate the challenges faced during the implementation by Wifi technology into Wireless personal area network using 60 GHz band in Wireless gigabit network and provide a solution where wireless personal area network can be implemented by reducing channel blockage ,Doppler spread and sever multipath environment problem.

Specification of Wireless Gigabit as per IEEE 802.11 amendment and 60GHz solution:

Wireless Gigabit technology will be supporting transmission speeds up to 7 Gbps which is 10 times more the 802.11n operating upon unlicensed 60GHZ frequency band which is multi-channel spectrum typically 7GHZ compared to 83.5 GHZ in 2.5GHz band in Wifi as it has much more spectrum available channels are much wider to enable multi-gigabit data rates .These wider channels in WiGig enable it to support application that require extremely fast transmission rates such as for uncompressed video transmission .WiGig is designed ground up for low power devices such as smartphones .High performance computer which supports WiGig has advanced power management system to minimize power loss. As it is based on IEEE 802.11 specification ,so it transparently switches for native Wifi band frequency operating on 802.11 networks .WiGig specification is as same as IEEE 802.11 a/b/g/n of MAC and PHY layer but having added features to improve performance over 60GHZ band .One new aspect in WiGig specification is that of beamformaing protocol in which devices with directional antennas discover each other to establish connection and once connection is made refinements to antenna setting are made to maximize transmission and receiving gains to data rates. Beamformaing is a process which to reduce interference a concentrated beam from directional antenna is focused between two devices. These antenna fine tune there setting so that maximum performance is reached to enable robust multi gigabit communication over 10 meters. From security point of view WiGig includes advanced encryption standard in Galious-counter mode requiring fewer computation per block as that of AES in 802.11 .For efficient data transfer rates packet aggregation and block acknowledgement is provided in the specification To maximize performance as the channel change ,adjustments to antenna setting are made so enable high speed data rates even.WiGig alliance- Multi Gigabit wireless structure will be tri-band having MAC and PHY layers implemented in hardware so that IP networking is achieved over 60 GHZ band .The devices are simpler and less expensive to produce so that they can communicate over all three bands 2.5GHZ ,5GHz,and 60GHZ.Protocol adaption layer is yet another layer in which support for audio/visual and input /Output is defined. Connectivity options such as HDMI,display port as well as USB /PCIe are supported.[1][White paper ,WiGig alliance,july 2011]

One interesting thing in PHY layer is the use unlicensed 60GHZ band which has much more spectrum available because the spectrum is divided in multiple channels so that to enable high data rates .Modulation and coding schemes includedare Orthogonal frequency division multiplexing (OFDM) so that signals travel over long distances and have greater delay spreads. Due to OFDM signal will be flexible in handling ostabtales thus achieving transmission desired speed upto 7 GBps The extension of .Single carrier (SC) mode in WiGig will support 4.05GB/s speeds so that low power devices are supported. To promote introperiablility OFDM and SC modes will share a common preamble and channel coding to reduced implementation complexity .[1]

MAC layer is being defined by WiGig Allience for point to point communication between devices. Specification defined in MAC layer will enable cable replacement and provide many features such as power management support for advanced usage models and integrating in exiting wifi networks and also having a strong built in security .Ability to switch seamlessly between 60GHz and 2.4 GHz and 5GHz is also defined in MAC layer. Hence if mobile device moves out of range of 60GHz thereby quickly fall back to low rate connection so seamlessly network connectivity is maintained. Power management is based upon scheduled access method so that devices goes in sleep mode when it not using the network to save power . Battery power devices such as mobile phones will especially benefit from it all because it may allow the devices to specifically tailor there power needs as per requirements. Support for 802.11MAC with backward compatibility towards 802.11 n is being provided by WiGig under MAC layer.

PAL’s (Protocol adaption layer) is one such feature implemented in hardware of upcoming devices which will support gigabit technology. PAL will provide with a solution by which PAL will allow implementers to integrate devices will switch protoal at different layers as per requirements Audio visual includes HDMI connection without the need of wires and HDCP which is protection of digital content when it is transmitter through the interfaces. Input out includes USB and PCIe connectors as it will allow docking mechanism so that peripheral devices can connect without the need for wires

As well as for CPU,storage and other I/O related operation, PAL will provide necessary multi gigabit synchronization at a very high speed It will negotiate is the peripheral connector by which CPU and other storage related operation are handled with a system .Main goal of PAL will be to facility high speed gigabit communication for offline and online processing.

60GHZ Solution and Why its will be successful :

Attractive features of unlicensed 60GHz is that there is abundance of spectrum available .Unlicensed nature of 60GHz proves as big plus point in terms of spectrum analysis as already low frequency bands are exiting WiFi infrastructure. Research in MIMO (Multiple input multiple out) [] in 802.11n is currently ongoing. Use of spatial multiplexing in MIMO has a huge boost in performance as the number of antenna packed in a small form factor at a reasonable cost would be practical constraint. To achieve high data rates in 2.5 GHz and 5Ghz band one way is to increase the channel bandwidth beyond 40GHz .Since MAC through put increases with overheard in channel capacity at a faster rate so MAC through put does not scale well with PHY data rate .Analysis in MAC efficiency [][] has proven that to reach 1Gbps transmission, PHY layer rate has to be in 3ms transmission opportunity (TXOP) requiring at least 2.4GHz of channel bandwidth. Reason why 60Ghz band is effective is show by ECMA[] and 15.3[] drafts as channels of 2.16 are divided in 60Ghz so wider channels enable high data rates .Draft put forward by 15.c shows again if modulation techniques such as QPSK(Quadrate phase shift keying )or 16-QAM( Quadrate amplitude modulation ) single carrier in PHY layer can achieve data rate of 2.664 GBPS and 4.965Gbps.

Advances in CMOS technology to built in expensive and low power transceiver is being done. Some of properties of 60GHz channel such as free space propagation loss can be compensated by using directional antenna as to achieve decent range .Another property which 60GHz exhibits is that strongest components must be in Line of sight but Non line of sight components also mostly exhibit as reflection .Sector antenna and adaptive antenna are being used in arrays to achieve shorter wavelengths of about 5mm by having different radiation patterns.

Challenges, Motivation and implementation of Wireless gigabit technology (60GHz) in Wireless Personal area networks:

Integration of Gigabit technology in Personal area network is one interesting area to looked upon. Investigating and implementation of Wireless personal area network with 60 GHz band has highlight few challenges in wireless infrastructure 60GHz unlicensed spectrum solution to short range wireless networking at 3.5 GHZ of transmissible spectrum is available worldwide .Europe already has 59-66GHz of mobile broadband whereas USA and Japan are behind with 56-64GHz ,59-66GHz of unlicensed application .The attenuation in 60GHZ signal with concrete wall and other material has been examined in [2] .Small room and conference halls are well suited for 60GHz transmission. Localization of signal proves to a positive impact on security. All due to beam width in this case is narrow because of presence of directive antenna operating at these frequencies. The required equipment for interfering with these is very expensive and not readily available. To make spectrum much more attractive, exploitation of attuetation in 60GHz signal for frequency reuse by isolation of nearby transmitters can form a excellent base for wireless communication

In [2] it has been explained that Wireless personal area networks are long haul backbone networks used as extension for wired fiber optic networks operating point to point using large directional antenna array so that as Operational ranges from 60GHz signal exceeds 1km of area with speeds upto 1.25Gbps.In [2] it has also been shown why motivation of these network is feasible .In [2] Wireless area networks are defined as short range network as 10m usually put in place for personal use such as small room or conference halls . In [2] challenges into when wireless personal area network are integrated with Gigabit 60GHz technology is show there by highlighting problems of transmission power due to path loss is sever as Fiirs equation to compute this effect clearly shows this phenomena its because 60 GHz signal suffers from a loss of power much more as compared to 2.5GHz and 5GHz band all because of short wavelength but can be compensated for increasing antenna gains .Solution to this problem is given in [2] that if we use small antenna loss in transmission power is much more feasible as at 60GHz for the given antenna gain scales inversely with square of wavelength. Doppler spread due to motion of wireless system ,channel blockage present due to Non line of sight ,Multi path fading environment and last but not least Network infrastructure because of need to generate and handle large amount of traffic are some of concerns in wireless personal area networks are examined as well in [2]

Conclusion

We have shown the specification currently in place for Wireless Gigabit communication with regard to IEEE’s new standard being developed in collaboration with Wireless gigabit alliance . They are leveraging the state of art millimeter technology so that widespread use of 60 GHz band is put in place in near future .Wireless docking, wireless display as well as Sync on go are some of important milestones in terms of applications are to be accomplished .Development of MAC and PHY layers adds up to high data rates achieved by Wireless gigabit communication.