HomeRF Working Group is led by the American Home RF Committee, was established in 1997, and its main tasks is to home users to establish interoperable voice and data communication networks. It launched HomeRF standard integrated voice and data transmission technology, the working frequency band for the 2.4GHz, the data transfer rate of 100Mbit / s, WLAN security in the main consideration in terms of access control and encryption technology.
Wireless Data Networks with a special emphasis on WLAN standards 12/23/2004 Wireless Data Networks 1 Agenda Why WLAN? WMAN, WWAN, WLAN, WPAN... Bluetooth & 802.15 IEEE802.11x HiperLAN/2 HomeRF Conclusions 12/23/2004 Wireless Data Networks 2 Why emphasis on WLANs? The market growth: From nearly zero to about 15 million customers during 2001 From about 10 to more than 180 WLAN products during 2001 Impressive figures in a down market! WLANs are the hottest topic in wireless world these days 12/23/2004 Wireless Data Networks 3 WMAN Wireless Metropolitan Area Network Very high rate, point-to- point communications LMDS: ~30GHz carrier 155 Mbps data rate IEEE802.16 WG From www.lmdswireless.com 12/23/2004 Wireless Data Networks 4 WWAN Wireless Wide Area Network Coverage : few kilometers High power consumption Slow Data Rates GSM : 9.6 Kbps IS-95 : 14.4 Kbps GPRS : 115 Kbps (theoretical) 40-50 Kbps (realized) Licensed 12/23/2004 Wireless Data Networks 5 WLAN Wireles Local Area Network Coverage : few hundred meters Data rate : tens of Mbps (depends on distance to the Access Point) Medium to high power consumption 802.11x , HiperLAN, HomeRF.... WLAN standards use unlicensed spectrum band 12/23/2004 Wireless Data Networks 6 WLAN WLAN configurations (from www.cisco.com) 12/23/2004 Wireless Data Networks 7 WPAN Wireless Personal Area Network Replace short-range cables in the offices and at home Coverage : ~10 meters Very low power consumption Ad-hoc connectivity Bluetooth, IrDA, HomeRF IEEE802.15 WG set to make Bluetooth the WPAN standard 12/23/2004 Wireless Data Networks 8 Bluetooth Ericsson initiative, but has many backers (Nokia, IBM, Intel, etc.) Technology developed by Bluetooth SIG, a not for- profit, free membership organization Apple and Microsoft made Bluetooth future bright clear : They announced that Bluetooth will be inherently supported by their OSs (early 2002) Microsoft presented first Bluetooth desktop peripherals (April, 2002) 12/23/2004 Wireless Data Networks 9 Bluetooth A BT chip is very cheap : ~ $5 Communication is quite secured Nearly 1Mbps data rate Supports voice and data BT operates at unlicensed 2.4GHz spectrum What else emits in this spectrum? Microwave ovens, light bulbs, HomeRF, 802.11b, etc. 12/23/2004 Wireless Data Networks 10 IEEE 802.11b The first (in market) and most widespread wireless networking standard Up to 11 Mbps (depends on the distance to the AP) The “Wireless Ethernet” Gets cheaper every day Two major drawbacks: Weak security High power consumption 12/23/2004 Wireless Data Networks 11 IEEE 802.11b Security is a major issue: Most corporations won’t implement WLAN in large scale if security is weak. 802.11b is protected with insufficient WEP(Wired Equivalent Privacy) Protocol Use of VPN and other security methods is strongly encouraged! 12/23/2004 Wireless Data Networks 12 IEEE 802.11b WECA (Wireless Ethernet Compatibility Alliance) certifies 802.11b products with Most major technology companies are WECA members Hundreds of products certified to date 12/23/2004 Wireless Data Networks 13 Interference Bluetooth and 802.11b operate at same frequencies, do they interfere? Yes and No. Due to different radio link access methods (DSSS vs. FHSS), most of the times they do not block each other. However, no one can guarantee that interference will not happen. This may affect real time audio/video streams. Solution: A Blue802® combo chip that supports both standards but prevents interference by not emitting at the same time! (demonstrated March, 2002) 12/23/2004 Wireless Data Networks 14 IEEE802.11b vs. Bluetooth Two standards operate in same frequency band, do they compete? This was the way they were seen until late 2001. Ex: Intel CEO announced that the Bluetooth is dead (July, 2001) and apologized (September, 2001) Current trend: Bluetooth and 802.11b complement each other! The current trend is welcomed by the product manufacturer companies 12/23/2004 Wireless Data Networks 15 IEEE 802.11b & Bluetooth You won’t build a “Bluetooth only” LAN because: It will be very expensive (remember the BT coverage and think of how many access points you’ll need) You’ll want to use Bluetooth for short-range communications because: 802.11b is power hungry, not suitable for small handheld devices BT is quite cheaper 802.11b doesn’t support voice 802.11b and Bluetooth will coexist. 12/23/2004 Wireless Data Networks 16 IEEE802.11a Operates at 5 GHz unlicensed spectrum 54 Mbps MAC layer same as 802.11b Physical layer different (OFDM) Lower range compared to 802.11b, but experiments show that superior data rates are observed at all distances WECA will certify compatible devices with “Wi-Fi5” logo 12/23/2004 Wireless Data Networks 17 IEEE 802.11a Power consumption three times less than 802.11b Faces much less interference compared to 802.11b Not compatible with 802.11b! Mixed 802.11a&b networks possible: Cisco Aironet 1200 - Mixed 802.11a&b access point (April, 2002) Mixed mode NIC’s on the way! 12/23/2004 Wireless Data Networks 18 IEEE 802.11x Other Work Groups also formed: 802.11i Solve the prolonged security issues with 802.11x’s WG operations almost completed 802.11g Above 20 Mbps Operates in 2.4GHz band Differs from 802.11b in PHY layer : 802.11g deploys OFDM Products expected late 2002 12/23/2004 Wireless Data Networks 19 HiperLAN/2 ETSI didn’t approve 802.11a: Unlicensed 5GHz spectrum is being used by satellite operators and military, therefore, Europe would allow a standard that has 1: Dynamic Frequency Selection 2: Transmit Power Control None of these exist in 802.11a! ETSI’s alternative : HiperLAN 12/23/2004 Wireless Data Networks 20 HiperLAN/2 Same PHY layer and data rate capabilities as 802.11a Advantages of HiperLAN/2 over 802.11a: QoS ATM based protocol – not just an Ethernet Greater spectrum efficiency and lower interference Almost everyone was sure that HiperLAN/2 will prevail in Europe, but.. 12/23/2004 Wireless Data Networks 21 HiperLAN/2 HiperLAN/2 was late... Philips announced that it won’t produce HiperLAN chips (October, 2001) Not a big surprise, maybe, as the chairman of 802.11 WG is a Philips employee... Intel declared that two coexisting 5GHz LAN standards will harm both parties... Ericsson (the main supporter) says they’re not interested in HiperLAN anymore (December, 2001) HiperLAN is over..... 12/23/2004 Wireless Data Networks 22 802.11 again.. Which fast wireless standard is going to be implemented in Europe? Not 802.11a, it lacks the two critical requirements.... It is 802.11h! This is simply 802.11a with Dynamic Frequency Selection and Transmit Power Control WG specs completed already... 12/23/2004 Wireless Data Networks 23 HomeRF An alternative standard that competed both with Bluetooth and 802.11b Incorporates DECT for voice and 802.11b’s CSMA/CA protocol for data Operates in 2.4 GHz unlicensed band Due to its physical layer, HomeRF is less vulnerable to interference compared to 802.11b HomeRF : 2 Mbps HomeRF2.0: 10 Mbps 12/23/2004 Wireless Data Networks 24 HomeRF Some strengths of HomeRF over 802.11b: Better security Lower power consumption Voice capabilites Easier setup QoS However, HomeRF2.0 was late: 10 Mbps 802.11b products have already entered the market and benefiting from economies of scale 802.11b soon became cheaper than HomeRF Intel abandoned HomeRF group (March 2001) in favor of 802.11b 12/23/2004 Wireless Data Networks 25 HomeRF Apparent success of 802.11b and Bluetooth caused HomeRF to change strategy: “None of these standards compete, they complement each other”: 12/23/2004 Wireless Data Networks 26 HomeRF HomeRF still striving for market share Currently working on a new, more competitive standard : HomeRF3.0 Main supporter : Siemens Currently HomeRF future doesn’t look very bright... 12/23/2004 Wireless Data Networks 27 Current Trends All-in-one cellular phone chips (GSM/GPRS, Bluetooth, GPS) WLAN-TDMA or WLAN-CDMA combo NICs Deutsche Telecom announces plans to integrate WLAN with WWAN (GSM, GPRS...) services Telcos are entering the market! Be prepared for organised, proprietary WLAN networks and combo phone bills! 12/23/2004 Wireless Data Networks 28 Conclusions IEEE sets the wireless data standards! 802.11x : Wireless LAN 802.15 : Wireless PAN 802.16 : Wireless MAN 12/23/2004 Wireless Data Networks 29 Conclusions Wireless data market will continue to grow very fast 802.11x doesn’t explicitly support voice, but there is need for it: VoIP standards are the next hot topic 12/23/2004 Wireless Data Networks 30
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