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Working Towards the Peaceful Coexistence of Wireless PANs, LANs, and WANs Northcon 2002 Tutorial Rob Roy Sr. Director, Business Development & Tech Strategy.

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Presentation on theme: "Working Towards the Peaceful Coexistence of Wireless PANs, LANs, and WANs Northcon 2002 Tutorial Rob Roy Sr. Director, Business Development & Tech Strategy."— Presentation transcript:

1 Working Towards the Peaceful Coexistence of Wireless PANs, LANs, and WANs Northcon 2002 Tutorial Rob Roy Sr. Director, Business Development & Tech Strategy Mobilian Corporation

2 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 2 Oct Northcon 2002 Tutorial Agenda n Introduction n Overview of , , and n Includes all current Task Groups and Study Groups n Coexistence: The Unlicensed band problem n Possible Solutions n Emerging trends n Higher speeds, More features, smart antennas n Convergence of , 15, 16, and 3G/4G mobile n A case study: The WPAN/WLAN combo radio n Conclusion

3 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 3 Oct Northcon 2002 Tutorial Introduction: About Mobilian…. n Fabless semiconductor company n Focus: TrueConnectivity n Multi-standard, integrated radio technology n Coexistence technology n Our view of the wireless future… n Multiple standards (PAN/LAN/WAN) will always exist n Each is optimized for a different environment n Integrated solutions and combinations of standards will improve seamless connectivity (It just works) and become the norm

4 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 4 Oct Northcon 2002 Tutorial Overview of WPAN/WLAN/WWAN n WPAN – n WLAN – n WMAN – n WWAN - Cellular n And how this fits with 3G/4G

5 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 5 Oct Northcon 2002 Tutorial Wireless PAN n Definition of a WPAN: nThe WPAN effort focuses on the development of consensus standards for Personal Area Networks or short distance wireless networks. These WPANs address wireless networking of portable and mobile computing devices such as PCs, Personal Digital Assistants (PDAs), peripherals, cell phones, pagers, and consumer electronics; allowing these devices to communicate and interoperate with one another. The goal is to publish standards, recommended practices, or guides that have broad market applicability and deal effectively with the issues of coexistence and interoperability with other wired and wireless networking solutions Short range cable replacement: typically <10m

6 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 6 Oct Northcon 2002 Tutorial The WPAN world…. n IEEE has 4 Task groups: n : The Original WPAN – aka Bluetooth n The Bluetooth protocol in an IEEE package, with PHY/MAC definitions n 2.4 – GHz ISM band n : Coexistence Task Group n Developing a Recommended Practice for coexistence between and b n : High rate WPAN n Designed for consumer multimedia applications, up to 55Mb/s data rate with Quality of Service (QoS) n a (SG): investigating alternative (UWB) physical layer n : Low cost, low power wireless for devices such as sensors, toys

7 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 7 Oct Northcon 2002 Tutorial Wireless LAN n Definition of a WLAN: n A wireless version of a local area networking protocol such as Ethernet. Since a WLAN interoperates with a wired LAN, its behavior must be compatible with other portions of the LAN infrastructure, such as TCP/IP. n WLAN must act like Ethernet over an unreliable medium n Uses CSMA/CA with backoff n Uses beacons to maintain synchronization n Uses CTS/RTS for hidden nodes

8 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 8 Oct Northcon 2002 Tutorial The WLAN Landscape…. n a: WLAN in the 5GHz band using OFDM n b: WLAN in the 2.4GHz band using CCK n e: Enhanced QoS n f: Inter-access point protocol n g: WLAN in the 2.4GHz band using OFDM n h: Modifications to a for Europe n i: Enhanced security (beyond WEP)

9 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 9 Oct Northcon 2002 Tutorial Wireless WAN n Definition of a WWAN: n A computer network that spans a relatively large geographical area. Typically, a WAN consists of two or more local-area networks (LANs). n Computers connected to a wide-area network are often connected through public networks, such as the telephone system. They can also be connected through leased lines or satellites. The largest WAN in existence is the Internet. n The largest wireless WAN is the mobile telephone system

10 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 10 Oct Northcon 2002 Tutorial What about BWA? n Broadband Wireless Access n Fixed wireless refers to wireless devices or systems that are situated in fixed locations, such as an office or home, as opposed to devices that are mobile, such as cell phones and PDAs. Fixed wireless devices normally derive their electrical power from utility mains, as opposed to portable wireless devices that normally derive their power from batteries.PDAs n The point-to-point signal transmissions occur through the air over a terrestrial microwave platform rather than through copper or fiber cables; therefore, fixed wireless does not require satellite feeds or local phone service. The advantages of fixed wireless include the ability to connect with users in remote areas without the need for laying new cables and the capacity for broad bandwidth that is not impeded by fiber or cable capacities.bandwidth

11 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 11 Oct Northcon 2002 Tutorial Broadband Wireless Access (BWA) n Replaces the last mile of copper or fiber with wireless n Can use LMDS, MMDS, or other spectrum n Generally fixed terminals n : Air interface for 10-60GHz licensed n a: 2-11GHz unlicensed n : Coexistence for same-band protocols n MBWA: Mobile broadband wireless access study group

12 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 12 Oct Northcon 2002 Tutorial Coexistence: The unlicensed band problem n Many standards have been developed for unlicensed bands: n 2.4GHz: FH, DS, b, Bluetooth, HomeRF, , n 5GHz: a, a n Devices sharing the same band will cause degradation n How much is acceptable ?

13 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 13 Oct Northcon 2002 Tutorial 5. Interference – An Issue in All Unlicensed Bands n 900 MHz (US) – cordless phones, some WAN, proprietary LAN, industrial heating n 2.4 GHz – cordless phones, Bluetooth, b (Wi-Fi), HomeRF, microwave ovens n 5 GHz – cordless phones, mobile satellite, a, HiperLAN1/2, HiperPAN, (proposed), microwave ovens, fixed wireless, radar MHz GHz GHz GHz Other ISM 24GHz 60GHz Multiple standards will exist in all bands Unlicensed band allocations

14 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 14 Oct Northcon 2002 Tutorial Bluetooth – Illustrative WPAN n Frequency hopper at 1600 hops/sec using 1 MHz wide hops n Typical use <10 meters; data rate = 1 Mbps (~ 728 Kbps) n Master – Slave MAC protocol n Provisions for synchronous voice links (SCO) n Expected to achieve ~ 800 MM units / year by 2004 Power Low Channel Mid ChannelHigh Channel 2.4 GHz GHz 1 MHz Wide

15 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 15 Oct Northcon 2002 Tutorial IEEE b – Illustrative WLAN n Direct sequence spread spectrum using ~20 MHz channels n Range <150m free space; data rate = 11Mbps (~ 5-7Mbps) n Ethernet like MAC layer – CSMA/CA n Expected to achieve ~ MM units / year by 2004; MM installed base Power Low Channel Mid ChannelHigh Channel 2.4 GHz GHz ~20 MHz Wide

16 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 16 Oct Northcon 2002 Tutorial Interference is Highly Likely n Bluetooth transmission in b passband destroys b signal n Likelihood of collision is 55% for 1500 byte packet n b CSMA/CA back-off algorithms exacerbate problem Power Low Channel Mid ChannelHigh Channel 2.4 GHz GHz

17 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 17 Oct Northcon 2002 Tutorial Coexistence Alternatives to Address Coexistence Technical Innovation Company Policy Standards Bodies

18 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 18 Oct Northcon 2002 Tutorial Standards Bodies Activities n Bluetooth SIG Coexistence WG n IEEE – Coexistence Taskgroup n Collaborative n Non-collaborative n Best Practices Recommendations by mid 2001 n IEEE – WPAN Taskgroup Coexistence Company Policy Technical Innovation Standards Bodies

19 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 19 Oct Northcon 2002 Tutorial Coexistence Technical Innovation Standards Bodies Company Policies Prohibiting One or the Other n Prohibit Bluetooth or b on campus n Prohibition of b manageable n Prohibition of Bluetooth problematic n Consumer-side purchases (cell phones, PDAs) n Companies moving away from this practice Company Policy

20 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 20 Oct Northcon 2002 Tutorial Technical Innovation – Leverage the Asset n Bypass 2.4 GHz for 5 GHz? n Technical solutions exist within the modules of the wireless subsystem to allow for differing levels of coexistence performance n PHY n MAC n Drivers Coexistence Company Policy Technical Innovation Standards Bodies (poor) User Experience (excellent) System-level Solutions (high) Performance Level (low) MAC-level Switching Adaptive Hopping (Bluetooth) Driver-level Switching Dual-mode Radio Switching Transmit Switching Collocation w/o Coexistence Mechanism Silicon-level Solutions

21 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 21 Oct Northcon 2002 Tutorial Interference Zones Significant degradation (<0.5 m) WLAN (Wi-Fi) and Bluetooth For separation >0.5 m: Throughput improves until 2 m Voice quality suffers w/o AFH inside 2 m For separation <0.5 m: Significantly reduced throughput Voice quality can be poor Non linear effects may occur Front end compression (blocking) Reciprocal mixing (intermods)

22 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 22 Oct Northcon 2002 Tutorial IEEE : Coexistence SG n Working on Recommended Practice document for Bluetooth b n Evaluated two types of techniques: n Collaborative (collocated systems can communicate) n Manual/Driver/MAC switching n Non-collaborative (no direct communication; e.g. AFH) n Draft document available from IEEE n Solutions in the market early 2002 n Bluetooth SIG also has Coexistence WG n Chaired by Dr. Tod Sizer of Lucent n Evaluating a number of techniques and interferers

23 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 23 Oct Northcon 2002 Tutorial Coexistence Methods in Development n Manual switching n Switch on side of computer n Driver-layer switching n Slow rate toggling between the two n MAC layer switching n High rate toggling between the two n Adaptive Frequency hopping n Bluetooth avoids interference by modifying hop sequence n System solution (collaborative) n Combines PHY, MAC, antenna, and software to allow fully simultaneous operation

24 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 24 Oct Northcon 2002 Tutorial Non-collaborative Techniques n WLAN Modified Data Rate / Packet Size n Continued likelihood of collision n Throughput reduced n Adaptive power control n In general, a good idea n Not defined for WLAN, needs improvement for BT n Adaptive Frequency Hopping n Effective for non-collocated usage models n Improves voice quality in frequency static interference n Increased b presence or BT presence hinders effectiveness n Requires regulation change for >0dBm and new Bluetooth profile/spec n Backward compatibility?

25 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 25 Oct Northcon 2002 Tutorial Collision avoidance Collision avoidance is like traffic management Time coincidence at different frequency is ok Same frequency at different times is ok Problem is when same time and frequency For non-collaborative such as adaptive FH, system must observe collisions for some time and decide which channels are bad to avoid them. Since predicting time of interference is difficult, AFH avoids the frequency altogether. F1 F2 F3 F4 WLAN (wideband) Bluetooth packets WLAN packets

26 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 26 Oct Northcon 2002 Tutorial AFH in action Frequency Time Slot b Bluetooth Transmits Bluetooth Does Not Tx

27 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 27 Oct Northcon 2002 Tutorial But, Interference can happen Additional solution needed besides AFH Interference Zones For separation >0.5 m: Throughput improves until 2 m Voice quality suffers w/o AFH inside 2 m For separation <0.5 m: Significantly reduced throughput Voice quality can be poor Non linear effects may occur Front end compression (blocking) Reciprocal mixing (intermods) AFH Optimized Zone 2-0.5m Collocated BT and Wi-Fi Needs AFH+additional solution Graceful degradation of BT & Wi-Fi ideal for AFH

28 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 28 Oct Northcon 2002 Tutorial Adaptive FH when collocated Collocated Adaptive hopping Link budget Class 3Class 1 Transmitted power0dBm+20dB m Path loss[1][1]34dB (0.5 m) 46dB (2 m) Adjacent channel loss (per specification) 35dB Power at detector-69dBm-61dBm b detection level -76dBm Detectable signal above threshold 7dB15dB [1][1] Assuming the path loss is free space at these short distances: Lp=40+20Log 10 (d), with d in meters. AFH does not solve the coexistence problem when Bluetooth and Wi-Fi are collocated Out of Band Link budget Out of Band Link budget

29 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 29 Oct Northcon 2002 Tutorial Collaborative Coexistence n Collaborative switching (time division model) n Potential improvements at the expense of performance n Driver layer collaboration n Switch between independent implementations n Easiest to implement, poorest performance (no BT SCO) n MAC layer collaboration (TDMA) n Switching between MACs on either traffic or time interrupt n Improves performance, still may not allow BT SCO n Enhanced MAC collaboration (Mobilian proposal to ) n Share information about what is happening now and next n Prioritize packets by traffic type n Defer conflicting packets where allowed by their protocol n Allows BT SCO with some WLAN degradation n When combined with PHY collaboration, allows Sim-Op

30 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 30 Oct Northcon 2002 Tutorial Collaboration avoids collisions Collaborative techniques define rules in advance for traffic management by direct communication between systems…no learning Traffic light (TDMA) totally prevents collisions Yield, 4-way stop, etc. are also valid rules F1 F2 F3 F4 Collaborative techniques schedule transmissions to avoid collisions WLAN (wideband)

31 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 31 Oct Northcon 2002 Tutorial Solution tradeoffs n Switching is simplest n No SCO n Significantly reduced throughput n Adaptive hopping requires FCC rules and Bluetooth spec changes n But supports voice well n No data degradation n System solution (MAC+PHY) requires collaboration (direct communication) and antenna design

32 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 32 Oct Northcon 2002 Tutorial Mixing the alphabet soup n In addition to the coexistence problem, there is the migration problem n Moving everybody to 5GHz doesnt solve the problem n Backward compatibility is the problem – hence the need for dual band support

33 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 33 Oct Northcon 2002 Tutorial 33 Proprietary and Confidential

34 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 34 Oct Northcon 2002 Tutorial Why WLAN – GPRS/3G interworking? n Requirements: n needs for global roaming and mobility n needs for high capacity - especially at hot spots n Market: n Users of PC-type terminals as a part of the 3G operator subscriber base n 3G packet service expansion with small investment costs n New services and applications n Increased overall customer value Increased revenue stream

35 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 35 Oct Northcon 2002 Tutorial Emerging trends n For a: higher speeds (> 100Mb/s) n Better QoS (802.11e) n Better security (802.11i) n Global harmonization (802.11h) n Faster speeds in 2.4GHz (802.11g) n Smart antenna technology n Ultrawide band for short range

36 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 36 Oct Northcon 2002 Tutorial What about Ultra Wide Band (UWB)? n No carrier – pulses injected directly into antenna n Spectral characteristics governed by pulse shape and antenna n Very broadband (>1GHz) n Potentially high data rates (>100Mb/s) n Regulatory bodies are skeptical because of the potential for interference

37 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 37 Oct Northcon 2002 Tutorial Radio Spectrum: A precious resource n Governments sell it n Allocation is now a huge international issue n WRC 2003 n Licensed spectrum predominates n But purchasing it is risky n Case in point: 3G!! n Case in point: 3G!! n Always a fight between commercial, civil, military n Unlicensed is attractive to commercial n Small barrier to entry into market n Poses large interference problem So nobody wants to pay for it, but everybody wants the reliability offered by clear spectrum!

38 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 38 Oct Northcon 2002 Tutorial How do you share spectrum? n Power n Frequency n Time n Code n Space The goal? To make every transmission from A to B reliable

39 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 39 Oct Northcon 2002 Tutorial We have made some advances…. n UWB? n Maybe its not really an advance – its Marconis spark gap generator! n Radical change in regulatory policies required n OFDM n Currently the favorite for emerging WLAN/WWAN systems n Works well with long delay spread n Combined with QAM, gets high data rates with good spectral efficiency n Shannon always gets in the way…. Moores Law doesnt apply to spectrum!!

40 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 40 Oct Northcon 2002 Tutorial The multi-standard/multi band radio n So called universal radio n DSP allows baseband functions to be performed flexibility n Doesnt and cant replace RF circuitry n May only be able to do one at a time n Today, these are more likely to be implemented as traditional building blocks on chip n Over time, there will be more DSP based approaches

41 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 41 Oct Northcon 2002 Tutorial The Trend? Multi-standard Radio n b-Bluetooth n Now a reality n Integrated approach yields best performance & price n b/a/g – (the whole bag) n Forward backward compatibility n WPAN-WLAN-WWAN n Works anytime, anywhere n Software defined in the future n Reconfigurable for multiple standards n Not optimal price-power- performance today WWAN (GPRS, UMTS) WLAN (802.11b/a/g) WPAN (Bluetooth)

42 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 42 Oct Northcon 2002 Tutorial A case study: the WPAN/WLAN combo radio n Combines b and Bluetooth n Manages interference using n signal processing n Both analog and digital n time scheduling n allows truly simultaneous operation n Virtually no loss in performance n Integrated solution drives down cost

43 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 43 Oct Northcon 2002 Tutorial The True 11b-Bluetooth combo solution: TrueRadio Integration n Decreases overall component count by 33% over current Wi-Fi only designs, and 50% over Wi-Fi and BT n 2-Chip solution n Single chip contains both radios and the other chip contains both basebands and MACs True Simultaneous Operation n Allows for simultaneous operation of BT and Wi-Fi with virtually no degradation to performance, for the best user experience True simultaneous operation – both ACL and SCO: Coexistence without Compromise

44 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 44 Oct Northcon 2002 Tutorial System-level Solution n b throughput near BT=OFF levels achieved by implementing dynamic system-level solution (includes MAC and PHY collaboration) n Can be implemented with NO changes to FCC rules OR either specification n Allows improved BT SCO performance as well! STA to AP WLAN Distance (m) b WLAN TP(Mb/s) BT=ON; b w/ No EnhancementsBT=ON; b w/ MAC-level Coll. BT=ON; b w/ Mobilian TRBT=OFF

45 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 45 Oct Northcon 2002 Tutorial Simultaneous Operation (Sim-Op) n The ability for Wi-Fi and Bluetooth to operate simultaneously, with virtually no degradation in performance. n Many emerging usage models where both protocols will need to operate simultaneously n Only Sim-Op provides seamless Coexistence Without Compromise

46 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 46 Oct Northcon 2002 Tutorial Sim-Op Demonstration n b with collocated interference – 80% throughput lost; remainder extremely choppy n TrueRadio b Provides full throughput restoration Source: Mobilian TrueRadio Demo – COMDEX 2000 Demo Set-up: * Notebook PC with collocated BT & b * BT node ~ 1 m away * b AP ~ 15 m away in walled office environment Source: Mobilian TrueRadio Demo – COMDEX 2000 Demo Set-up: * Notebook PC with collocated BT & b * BT node ~ 1 m away * b AP ~ 15 m away in walled office environment b; BT=OFF b with TrueRadio; BT=ON b; BT=ON

47 Convergence of WPAN, WLAN, and WWAN – Rob Roy, Mobilian Corporation 47 Oct Northcon 2002 Tutorial Conclusion n Wireless combines applications for portable as well as mobile markets n Users will demand increased mobility and performance n Multi-standard radio will allow this heterogeneous mix to be cost effective n Software will be needed to allow these multi- standard radios to roam across systems n Multi-standard will show a trend toward increasing DSP usage in the baseband/MAC


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