HiperLAN was developed as a wireless local area network standard by ETSI to provide higher data rates than early 802.11 standards. HiperLAN Type 1 achieved data rates up to 2 Mbps for ad hoc networking. HiperLAN Type 2 was later developed to provide connection-oriented service up to 54 Mbps, with quality of service guarantees, security, and flexibility. It uses OFDM in the 5 GHz spectrum for robust transmission. While early products only achieved 25 Mbps, the standard provides a framework for higher speeds as technologies advance. HiperLAN is intended to complement wired networks by providing wireless connectivity in hotspot areas like offices, homes, and public places.

1. HIPERLANHIgh PErformance Radio Local Area Networkswww.ustudy.in

2. IntroductionRoughly speaking there are two types of wireless networks:

3. Local Area Networks (LAN)

4. Bluetooth, 802.11 Family, HiperLAN Family, HomeRF...

5. Wide Area Networks (WAN)

6. GSM, 3G, 4G, Iridium...www.ustudy.in

7. Mobility and data rates for communications standardswww.ustudy.in

8. Two main standards families for Wireless Lan:

9. IEEE 802.11 (802.11b, 802.11a, 802.11g...)

10. ETSI HiperLAN (HiperLAN Type 1, Type 2, HiperAccess, HiperLink...)

11. HiperLAN Familywww.ustudy.in

12. Motivation of HiperLAN Massive Growth in wireless and mobile communications

13. Emergence of multimedia applications

14. Demands for high-speed Internet access

15. Deregulation of the telecommunications industrywww.ustudy.in

16. The History, Present and Future HiperLAN Type 1

17. Developed by ETSI during 1991 to 1996

18. Goal: to achieve higher data rate than IEEE 802.11 data rates: 1~2 Mbps, and to be used in ad hoc networking of portable devices

19. Support asynchronous data transfer, carrier-sense multiple access multiple access with collision avoidance (CSMA/CA), no QoS guaranteed.

20. Products

21. Proxim's High Speed RangeLAN5 product family (24Mbps; 5GHz; QoS guaranteed)

22. RadioLAN’s products for indoor wireless communication (10Mbps; 5GHz; Peer-to-Peer Topology)www.ustudy.in

23. HiperLAN Type 2

24. Next generation of HiperLAN family: Proposed by ETSI BRAN (Broadband Radio Access Networks) in 1999, and is still under development.

25. Goal: Providing high-speed (raw bit rate ~54Mbps) communications access to different broadband core networks and moving terminals

26. Features: connection-oriented, QoS guaranteed, security mechanism, highly flexibility

27. Product: Prototypes are available now, and commercial products are expected at the end of 2001 (Ericsson).

28. HiperAccess and HiperLink

29. In parallel to developing the HIPERLAN Type 2 standards, ETSI BRAN has started work on standards complementary to HIPERLAN Type 2www.ustudy.in

30. Typical application scenariosHiperLAN: A complement to present-day wireless access systems, giving high data rates to end-users in hot-spot areas.

31. Typical app. Environment: Offices, homes, exhibition halls, airports, train stations, etc.

32. Different with Bluetooth, which is mainly used for linking individual communication devices within the personal area networkwww.ustudy.in

33. www.ustudy.in

34. II. Hiperlan2 System OverviewFeatures5 GHz technology, up to 54 Mbit/s

35. Generic architecture supporting:Ethernet, IEEE 1394, ATM, 3G etc.

36. Connection-oriented with QoS per conn.

37. Security - authentication & encryption

38. Plug-and-play radio network using DFS

39. Optimal throughput schemewww.ustudy.in

40. ArchitectureControl PlaneUser PlaneCLMACACFDCCRRCECCACRLCMACPHYDLCHiperLAN Type 1 Reference ModelPHYHiperLAN Type 2 Reference ModelMAC: Medium Access Sub layer EC: Error ControlCAC: Channel Access Control Sub layer RLC: Radio Link ControlPHY: Physical Layer RRC: Radio Resource ControlDLC: Data Link Control Layer ACF: Association Control FunctionCL: Convergence Layer DCC: DLC Connection Controlwww.ustudy.in

41. Physical LayerData units on physical layer: Burst of variable length, consist of a preamble and a data field

42. Reference configuration1: information bits2: scrambled bits3: encoded bits4: interleaved bits5: sub-carrier symbols6: complex baseband OFDM symbols7: PHY burstswww.ustudy.in

43. Spectrum plays a crucial role in the deployment of WLAN

44. Currently, most WLAN products operate in the unlicensed 2.4GHz band, which has several limitations: 80MHz bandwidth; spread spectrum technology; interference

45. Spectrum allocation for Hiperlan2www.ustudy.in

46. Modulation scheme: Orthogonal frequency-division multiplexing (OFDM)

47. Robustness on highly dispersive channels of multipath fading and intersymbol interference

48. Spectrally efficient

49. Admits great flexibility for different modulation alternatives

50. Facilitated by the efficiency of FFT and IFFT algorithms and DSP chips

51. Hiperlan2: 19 channels (20MHz apart). Each channel divided into 52 subcarrierswww.ustudy.in

52. Encoding: Involves the serial sequencing of data, as well as FEC

53. Key feature: Flexible transmission modes

54. With different coding rates and modulation schemes

55. Modes are selected by link adaptation

56. BPSK, QPSK as well as 16QAM (64QAM) supportedwww.ustudy.in

57. Data Link Control Layerwww.ustudy.in

58. Three main control functionsAssociation control function (ACF): authentication, key management, association, disassociation, encryption

59. Radio resource control function (RRC): handover, dynamic frequency selection, mobile terminal alive/absent, power saving, power control

60. DLC user connection control function (DCC): setup and release of user connections, multicast and broadcastConnection-orientedAfter completing association, a mobile terminal may request one or several DLC connections, with one unique DLC address corresponding to each DLC connection, thus providing different QoS for each connectionwww.ustudy.in

61. DLC: MAC Sub layerBasic frame structure (one-sector antenna)www.ustudy.in

62. BCH (broadcast channel): enables control of radio resources

63. FCH (frequency channel): exact description of the allocation of resources within the current MAC frame

64. ACH (access feedback channel): conveys information on previous attempts at random access

65. Multibeam antennas (sectors) up to 8 beams supported

66. A connection-oriented approach, QoS guaranteedwww.ustudy.in

67. HiperLAN implements QoS through time slotsQoS parameters: bandwidth, bit error rate, latency, and jitter

68. The original request by a MT to send data uses specific time slots that are allocated for random access.

69. AP grants access by allocating specific time slots for a specific duration in transport channels. The MT then sends data without interruption from other MT operating on that frequency.

70. A control channel provides feedback to the sender.www.ustudy.in

71. DLC: Error ControlAcknowledged mode: selective-repeat ARQ

72. Repetition mode: typically used for broadcast

73. Unacknowledged mode: unreliable, low latencyDLC: other featuresRadio network functions: Dynamic frequency selection; handover; link adaptation; Multibeam antennas; power control

74. QoS support: Appropriate error control mode selected; Scheduling performed at MAC level; link adaptation; internal functions (admission, congestion control, and dropping mechanisms) for avoiding overloadwww.ustudy.in

75. IV. ConclusionWill HiperLAN standards replace 802.11?

76. There will be a fight between connection and connectionless camps Hiperlan2/802.11a

77. Current products under development and becoming available only offer 25Mbps

78. Hiperlink 155Mbps data rates still some way off

79. Wireless: Useful as an adjunct to the wired worldwww.ustudy.in

80. The End …… Thank You ……www.ustudy.in