Wireless Interrupt: Inter-Device Signaling in Next Generation Wireless Networks

[seminar class]

Presented By,
Manoj Sudharshan J

---

[attachment=12273]
Wireless Interrupt: Inter-Device Signaling in Next Generation Wireless Networks
ABSTRACT
 Recent advances in wireless technique which has led to the rapid reproduction of wireless devices.
 Even greater increase in number of wireless services.
 FLEXIBILITY and INTEROPERABILITY are the main factors for the success of future wireless networks
 Main aim of this is to investigate the Technical issues that must be overcome in dealing with flexibility and interoperability
 Device discovery is the main issue
 Therefore Wireless Interrupt has been proposed to solve the problem of Device discovery
INTRODUCTION TO NEXT GENERATION WIRELESS NETWORK
 The prediction of future wireless technology is difficult but the trends in which it has emerged and developed is unalterable
 There are severable aspects of this trend
 First, there will be lots of wireless of all kinds
 Second, the demand for mobility and portability will keep increasing
 Third, there will be greater demand for integrated services
 For wireless success to continue necessary features should be provided to keep the trend characterized
RELATED WORK
Flexibility and Interoperable Wireless Networks
 In Wireless different technologies have been developed each supporting a specific use
 Eg: Recent ipods have come with 3G, Wifi and Bluetooth interfaces.
 Such parallel brewing of technologies will hinder further innovations mainly due to two limitations
 A separate radio hardware architecture
 Devices using different protocols cannot directly communicate with each other
 A device is Flexible if it can support multiple wireless modes in a single hardware configuration
 Two or more devices are Interoperable if it can communicate with another device that employs a different protocol
 Software Defined Radios(SDR’s) can be reconfigured to enable the flexible transformation of device from one mode to another
 But putting SDR’s into a practical use is a challenging task due to performance and cost reasons
Software Defined Radio Model
Device Discovery
 First step in constructing the interoperable networks is to enable heterogeneous devices to discover each other
 Device discovery is not an easy task since a device should discover another device without any a priori information such as protocols, carrier frequency and existence of other devices
 There are 2 approaches to solve this problem
 To actively send alert messages
 To passively listen to other signals and analyze them
WIRELESS INTERRUPT: CONCEPT
• Overview of Wireless Interrupt
 To solve the problem of device discovery, explicit signaling is used which we call Wireless Interrupt
• Establishing the Interrupt-Request Line Over the Air
 Since there is no dedicated Interrupt request line in Wireless Interrupt it proves to be a great challenge
 A solution to this problem is to create a Control channel which is a frequency band dedicated to control message signal
ASYNCHRONOUS RENDEZVOUS SCHEMES
 Synchronization between Tx and Rx is not possible in heterogeneous wireless environment
 Following 2 properties should be satisfied for ARS
 The interrupt signal must be transmitted over N channels with equal probabilities
 Two devices make a rendezvous in N channels with equal probabilities
 Time should be assumed to be divided into slots of length ‘μ’
Scanning
 A concept Expected overlap is introduced here
 In simple scanning Tx transmits its interrupt signal in one channel at a time while the receiver uniformly picks a channel and monitors it
 Expected Overlap for Simple Scanning is given by
 Enhanced Scanning can be done by Scrambling the order of channel hops by defining (N-1) sequences
 Tx then selects one of the (N-1) hopping sequences to transmit the interrupt signals
 Expected Overlap for Enhanced Scanning is given by
Drawback of Scanning
 The drawback of Scanning is that the receiver sits in one channel to monitor signals.
 If that channel is bad (e.g. interference) for the monitor duration of the receiver, then it cannot pick up any of the signals.
 It is, therefore, preferred to make the receiver channel-hop along with the transmitter to add a degree of channel diversity, and it must be done carefully to not break the rendezvous guarantee, leading to the next scheme.
Quorum-Based
 A quorum system is a set S = {S1, S2, ..., SN}, where Si is a subset of some universe U, such that ∀Si, Sj ∈ S, Si∩Sj ̸= ϕ
 Given a quorum system S over U, a transmitter and a receiver pick quorums Si and Sj , respectively
 The transmitter transmits an interrupt signal via the channels in Si in a certain order, repeatedly
 The receiver visits the channels in Sj in a certain order, repeatedly, each time circularly shifting the order by one.
• Quorum System Table and Scheme
PRELIMINARY TESTS
• TTR - Time to rendezvous
• CBR - Constant bit rate
WIRELESS SERVICES
 Common examples of wireless equipment in use today include:
 Professional LMR (Land Mobile Radio) and SMR (Specialized Mobile Radio)
 Consumer Two way radio
 The Amateur Radio Service
 Consumer and professional Marine VHF radios
 Cellular telephones and pagers
 Global Positioning System (GPS)
 Cordless telephone sets
 Satellite television
APPLICATIONS
 Security systems
 Cellular telephone (phones and modems)
 Wi-Fi
 Computer interface devices
MERITS AND DEMERITS
MERITS
 Mobility
 Neat and easy Installation
 Less cost
 More user supported
 Flexible
DEMERITS
 Lower speed
 Less secure
 More complex
 Attenuation(Affected by surrounding environment)
CONCLUSION AND FUTURE WORK
 In this paper, the research authors has examined the issue of networking flexible wireless devices, such as software defined radios (SDRs), by proposing a signaling mechanism called Wireless Interrupt
 They have proposed two channel rendezvous schemes and analyzed their characteristics.
 They argued that such inter-device signaling and device discovery is the first step towards the construction of Next Generation Wireless networks