Mobile Cellular Systems - Alak Roy

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High priority for Handoff • In non-prioritization schemes, new calls and handoff calls are treated the same way. Idle channels of BS are assigned due to FCFS basis. • Does not provide lower forced termination prob • In order to provide lower forced termination prob, prioritization schemes assigns more channels to the handoff calls. • Two prioritization schemes are: Guard Channels (GC) and Queuing Handoff calls (QHC). 36
Guard Channels(GC) • Reserves some fixed or adaptively changing number of channels for handoff calls only. • The rest of the channels are used by new and handoff calls. • Forced termination prob is decreased. • Cost is an increase in call blocking prob, decrease in total carried traffic. • BSs can get number of MSs in pre handover zone (PHZ) from neighboring BSs and accordingly reserve that many number of guard channels. • Assign number of channels adaptively. When FTP exceeds a predefined limit, the guard channel no is increased. The no of guard channels is decreased in case BS does not use reserved guard channels significantly. 37
Page 1 and 2: SLIDE #2.1 Mobile Cellular Systems
Page 3 and 4: Cellular Implementations (Gs) • 1
Page 5 and 6: Cellular Implementations(Gs) • 4G
Page 7 and 8: Frequency Division Duplex (FDD) mob
Page 9 and 10: Number of User Channels in AMPS •
Page 11 and 12: Cellular Architecture MSC PSTN MS B
Page 13 and 14: Hexagonal Cells 13
Page 15: Example: K = 7 15
Page 18 and 19: Nyquist Bandwidth (for noiseless ch
Page 20 and 21: Signal-to-Noise Ratio • Ratio of
Page 22 and 23: Example of Nyquist and Shannon Form
Page 24 and 25: 24 HANDOFF IN CELLULAR SYSTEMS
Page 26 and 27: Handoff Decisions • Usually based
Page 28 and 29: Traditional Handoff Algorithms Choo
Page 30 and 31: Example Receiver Threshold 30
Page 32 and 33: Who and When • Who initiates hand
Page 34 and 35: Types of Handoff • Hard handoff -
Page 38 and 39: Queuing Handoff Calls (QHC) • Que
Page 40 and 41: Queuing Handoff Calls • QHC can b
Page 42: Other practical problems with hando

Mobile Cellular Systems - Alak Roy

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