1 / 8

hub or switch

H1 remains in same IP subnet: IP address can remain same switch: which AP is associated with H1? self-learning (Ch. 5): switch will see frame from H1 and “remember” which switch port can be used to reach H1 AP2 broadcast H1’s MAC to switch. router. 802.11: mobility within same subnet.

pedroza
Download Presentation

hub or switch

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. H1 remains in same IP subnet: IP address can remain same switch: which AP is associated with H1? self-learning (Ch. 5): switch will see frame from H1 and “remember” which switch port can be used to reach H1 AP2 broadcast H1’s MAC to switch router 802.11: mobility within same subnet hub or switch BBS 1 AP 1 AP 2 H1 BBS 2 6: Wireless and Mobile Networks

  2. CDMA Principle (6.2.1) • Code Division Multiple Access • Wide spectrum technique • All users use the full spectrum • Users with different codings not interfere • Each bit is encoded by much high rate signal (code) • Receiver can recover the bit with the corresponding code 6: Wireless and Mobile Networks

  3. CDMA example 6: Wireless and Mobile Networks

  4. Working with multiple users • How to extract data when multiple users transmit at the same time? • Assumptions: • Interfering signals are additive • Signal 1+1+1+(-1) = 2 • New signals in the air (N senders): Same decoding formula! 6: Wireless and Mobile Networks

  5. Why extract correctly By each user? A: user codes are orthogonal 6: Wireless and Mobile Networks

  6. 802.15 MAC and Bluetooth • 802.11 MAC • 11 Mbps – 54 Mbps • Up to 100 meters range • 802.15 MAC • Wireless personal area network (WPAN) • < 10 meters range • Simple (cheap) device, low power assumption • Cable, wire replacement • E.g., mouse, keyboard, headphone • Example: Bluetooth 6: Wireless and Mobile Networks

  7. Bluetooth • Physical layer properties: • 2.4GHz unlicensed spectrum • Frequency-hopping spread spectrum • 79 channels with different frequencies • TDM transmit: jump among channels with preset sequences (coding) • Up to 721bps (802.11 is 11 Mbps to 54 Mbps) 6: Wireless and Mobile Networks

  8. Bluetooth • Ad hoc network structure • One master, <=7 slaves • Odd time slot: master • Even time: slaves • Parked: inactive devices • Problem: slow speed can be achieved by RF device • Much cheaper, simpler 6: Wireless and Mobile Networks

More Related