Chapt 05

Information about Chapt 05

Published on January 16, 2008

Author: Susann

Source: authorstream.com

Content

Chapter 5:  Chapter 5 The Cellular Concept Outline:  Outline Cell Shape Actual cell/Ideal cell Signal Strength Handoff Region Cell Capacity Traffic theory Erlang B and Erlang C Cell Structure Frequency Reuse Reuse Distance Cochannel Interference Cell Splitting Cell Sectoring Cell Shape:  Cell Shape Cell R (a) Ideal cell (b) Actual cell R R R R (c) Different cell models Impact of Cell Shape and Radius on Service Characteristics:  Impact of Cell Shape and Radius on Service Characteristics Signal Strength:  Signal Strength Select cell i on left of boundary Select cell j on right of boundary Ideal boundary Cell i Cell j -60 -70 -80 -90 -100 -60 -70 -80 -90 -100 Signal strength (in dB) Signal Strength:  Signal Strength Signal strength contours indicating actual cell tiling. This happens because of terrain, presence of obstacles and signal attenuation in the atmosphere. -100 -90 -80 -70 -60 -60 -70 -80 -90 -100 Signal strength (in dB) Cell i Cell j Handoff Region:  Handoff Region BSi Signal strength due to BSj E X1 Signal strength due to BSi BSj X3 X4 X2 X5 Xth MS Pmin Pi(x) Pj(x) By looking at the variation of signal strength from either base station it is possible to decide on the optimum area where handoff can take place. Handoff Rate in a Rectangular:  Handoff Rate in a Rectangular  R2 R1 X2 X1 Since handoff can occur at sides R 1 and R 2 of a cell where A=R 1 R 2 is the area and assuming it constant, differentiate with respect to R1 (or R 2) gives Total handoff rate is H is minimized when =0, giving  Cell Capacity:  Cell Capacity Average number of MSs requesting service (Average arrival rate):  Average length of time MS requires service (Average holding time): T Offered load: a = T e.g., in a cell with 100 MSs, on an average 30 requests are generated during an hour, with average holding time T=360 seconds. Then, arrival rate =30/3600 requests/sec. A channel kept busy for one hour is defined as one Erlang (a), i.e., Cell Capacity:  Cell Capacity Average arrival rate during a short interval t is given by  t Assuming Poisson distribution of service requests, the probability P(n, t) for n calls to arrive in an interval of length t is given by Assuming  to be the service rate, probability of each call to terminate during interval t is given by  t. Thus, probability of a given call requires service for time t or less is given by Erlang B and Erlang C:  Erlang B and Erlang C Probability of an arriving call being blocked is where S is the number of channels in a group. Erlang B formula Erlang C formula where C(S, a) is the probability of an arriving call being delayed with a load and S channels. Probability of an arriving call being delayed is Efficiency (Utilization):  Efficiency (Utilization) Example: for previous example, if S=2, then B(S, a) = 0.6, ------ Blocking probability, i.e., 60% calls are blocked. Total number of rerouted calls = 30 x 0.6 = 18 Efficiency = 3(1-0.6)/2 = 0.6 Cell Structure:  Cell Structure F2 F3 F1 F3 F2 F1 F3 F2 F4 F1 F1 F2 F3 F4 F5 F6 F7 (a) Line Structure (b) Plan Structure Note: Fx is set of frequency, i.e., frequency group. Frequency Reuse:  Frequency Reuse F1 F2 F3 F4 F5 F6 F7 F1 F2 F3 F4 F5 F6 F7 F1 F2 F3 F4 F5 F6 F7 F1 F2 F3 F4 F5 F6 F7 F1 F1 F1 F1 Fx: Set of frequency 7 cell reuse cluster Reuse distance D Reuse Distance:  Reuse Distance F1 F2 F3 F4 F5 F6 F7 F1 F2 F3 F4 F5 F6 F7 F1 F1 Reuse distance D For hexagonal cells, the reuse distance is given by R where R is cell radius and N is the reuse pattern (the cluster size or the number of cells per cluster). Reuse factor is Cluster Reuse Distance (Cont’d):  Reuse Distance (Cont’d) The cluster size or the number of cells per cluster is given by where i and j are integers. N = 1, 3, 4, 7, 9, 12, 13, 16, 19, 21, 28, …, etc. The popular value of N being 4 and 7. i j 60o Reuse Distance (Cont’d):  Reuse Distance (Cont’d) (b) Formation of a cluster for N = 7 with i=2 and j=1 60° 1 2 3 … i j direction i direction (a) Finding the center of an adjacent cluster using integers i and j (direction of i and j can be interchanged). i=2 i=2 j=1 j=1 j=1 j=1 j=1 j=1 i=2 i=2 i=2 i=2 Reuse Distance (Cont’d):  Reuse Distance (Cont’d) (c) A cluster with N =12 with i=2 and j=2 (d) A Cluster with N = 19 cells with i=3 and j=2 j=2 j=2 j=2 j=2 j=2 j=2 i=2 i=2 i=2 i=2 i=2 i=2 Cochannel Interference:  Cochannel Interference Mobile Station Serving Base Station First tier cochannel Base Station Second tier cochannel Base Station R D1 D2 D3 D4 D5 D6 Worst Case of Cochannel Interference:  Worst Case of Cochannel Interference Mobile Station Serving Base Station Co-channel Base Station R D1 D2 D3 D4 D5 D6 Cochannel Interference:  Cochannel Interference Cochannel interference ratio is given by where I is co-channel interference and M is the maximum number of co-channel interfering cells. For M = 6, C/I is given by where  is the propagation path loss slope and  = 2~5. Cell Splitting:  Cell Splitting Large cell (low density) Small cell (high density) Smaller cell (higher density) Depending on traffic patterns the smaller cells may be activated/deactivated in order to efficiently use cell resources. Cell Sectoring by Antenna Design:  Cell Sectoring by Antenna Design 60o 120o (a). Omni (b). 120o sector (e). 60o sector 120o (c). 120o sector (alternate) a b c a b c (d). 90o sector 90o a b c d a b c d e f Cell Sectoring by Antenna Design:  Cell Sectoring by Antenna Design Placing directional transmitters at corners where three adjacent cells meet A C B X Worst Case for Forward Channel Interference in Three-sectors :  Worst Case for Forward Channel Interference in Three-sectors BS MS R D + 0.7R D BS BS BS Worst Case for Forward Channel Interference in Three-sectors (Cont’d):  Worst Case for Forward Channel Interference in Three-sectors (Cont’d) BS MS R D’ D BS BS BS D Worst Case for Forward Channel Interference in Six-sectors:  Worst Case for Forward Channel Interference in Six-sectors

Related presentations


Other presentations created by Susann

Athletic Footwear Industry
31. 03. 2008
0 views

Athletic Footwear Industry

radioactivity 1
07. 02. 2008
0 views

radioactivity 1

Africa Unit 3
02. 04. 2008
0 views

Africa Unit 3

Market Research
03. 03. 2008
0 views

Market Research

module 1 intro
08. 05. 2008
0 views

module 1 intro

zly
07. 05. 2008
0 views

zly

031016 inhale montreal
02. 05. 2008
0 views

031016 inhale montreal

new leg
02. 05. 2008
0 views

new leg

JM UWA Luncheon Oct2007
30. 04. 2008
0 views

JM UWA Luncheon Oct2007

Tutorial
24. 04. 2008
0 views

Tutorial

NSW China Briefing
22. 04. 2008
0 views

NSW China Briefing

Weber Fall06
18. 04. 2008
0 views

Weber Fall06

SharksPP
17. 04. 2008
0 views

SharksPP

Dennill Managing Your Risk
09. 01. 2008
0 views

Dennill Managing Your Risk

AAS Presentation
10. 01. 2008
0 views

AAS Presentation

GANG Powerpoint
11. 01. 2008
0 views

GANG Powerpoint

885
15. 01. 2008
0 views

885

Class11
09. 01. 2008
0 views

Class11

Mercantilism
18. 01. 2008
0 views

Mercantilism

ppe p sp
20. 01. 2008
0 views

ppe p sp

training docs
21. 01. 2008
0 views

training docs

eukaryoticorgs
22. 01. 2008
0 views

eukaryoticorgs

LimitedBrandsPresent ation
04. 02. 2008
0 views

LimitedBrandsPresent ation

MLA outreach presentation
15. 01. 2008
0 views

MLA outreach presentation

CenturyTheatre Ad Sept06 gg
15. 01. 2008
0 views

CenturyTheatre Ad Sept06 gg

LutzWalter
22. 01. 2008
0 views

LutzWalter

secondary aluminum
12. 02. 2008
0 views

secondary aluminum

2 3 Ben Sekamatte
25. 01. 2008
0 views

2 3 Ben Sekamatte

Clara Qualizza
19. 01. 2008
0 views

Clara Qualizza

Session 4 Oper vs Aux
28. 01. 2008
0 views

Session 4 Oper vs Aux

Ch5 6 10 14
29. 01. 2008
0 views

Ch5 6 10 14

Rites of Passage
29. 01. 2008
0 views

Rites of Passage

Jonah Presentation
30. 01. 2008
0 views

Jonah Presentation

tjea
07. 02. 2008
0 views

tjea

firesafety
07. 02. 2008
0 views

firesafety

Wiriya Suwannet
10. 01. 2008
0 views

Wiriya Suwannet

s Oceans
13. 02. 2008
0 views

s Oceans

Freeman
20. 02. 2008
0 views

Freeman

Forage Diseases
27. 02. 2008
0 views

Forage Diseases

SlaneP constraints
22. 01. 2008
0 views

SlaneP constraints

EPD2 Present and Future
28. 02. 2008
0 views

EPD2 Present and Future

INSOMNIA DrJeanGrenier Nov 2007
28. 02. 2008
0 views

INSOMNIA DrJeanGrenier Nov 2007

SAAS Gianessi
28. 01. 2008
0 views

SAAS Gianessi

5th Grade FCAT Review
14. 03. 2008
0 views

5th Grade FCAT Review

talent engine discussion guide
16. 03. 2008
0 views

talent engine discussion guide

Lecture14 TheEarth
11. 03. 2008
0 views

Lecture14 TheEarth

GEO205 powerpoint 12
27. 03. 2008
0 views

GEO205 powerpoint 12

Parasitology Basic 07
28. 03. 2008
0 views

Parasitology Basic 07

world geography
15. 04. 2008
0 views

world geography

Irwin
16. 04. 2008
0 views

Irwin

BuildingWordnets
05. 02. 2008
0 views

BuildingWordnets

Douglas Morgan
16. 01. 2008
0 views

Douglas Morgan

Wien
05. 03. 2008
0 views

Wien

NSO 2007
14. 01. 2008
0 views

NSO 2007

GeneralOutreachKansas
29. 01. 2008
0 views

GeneralOutreachKansas

Rita Tucker
25. 01. 2008
0 views

Rita Tucker

Bob Moseley Kawagebo
05. 02. 2008
0 views

Bob Moseley Kawagebo

michigan0314b
15. 01. 2008
0 views

michigan0314b

Canning Fruits
06. 02. 2008
0 views

Canning Fruits

English Labofa EGO Nordic
05. 03. 2008
0 views

English Labofa EGO Nordic

SlidesWithNotes
14. 02. 2008
0 views

SlidesWithNotes

GMkk
24. 01. 2008
0 views

GMkk

20030909152346 EVI
13. 01. 2008
0 views

20030909152346 EVI

07nrm
22. 01. 2008
0 views

07nrm

praca5
03. 03. 2008
0 views

praca5

majingweili
14. 04. 2008
0 views

majingweili

Module3Presentation
25. 02. 2008
0 views

Module3Presentation

Jones NDDA
20. 01. 2008
0 views

Jones NDDA

Thornton CreatingAClimate
17. 01. 2008
0 views

Thornton CreatingAClimate

FirstHalfStudyGuide
15. 02. 2008
0 views

FirstHalfStudyGuide