Gsm Channel
12
76 FACCH MESSAGES • Connection establishment from SDCCH to TCH • End validation of a SDCCH-TCH commutation • Characteristics of the future used BS after handover • Connection establishment to BS after handover • Validation of an handover SACCH MESSAGES Measures: - power level of the communication - quality level of the communication - level on the beacon frequency of the neighboring cells • Timing Advance • Power Control • SMS TCH MESSAGES • Speech • Data • Handover Access message (uplink) SDCCH MESSAGES • Request for a SDCCH assignment • Request for the end of channel assignment • Order of commutation from SDCCH to TCH • SMS Logical Channel Description (1/2)
description
Gsm Channel
Transcript of Gsm Channel
76
FACCH MESSAGES• Connection establishment from
SDCCH to TCH
• End validation of a SDCCH-TCH commutation
• Characteristics of the future used BS after handover
• Connection establishment to BS after handover
• Validation of an handover
SACCH MESSAGESMeasures:
- power level of the communication
- quality level of the communication
- level on the beacon frequency of the neighboring cells
• Timing Advance
• Power Control
• SMS
TCH MESSAGES
• Speech
• Data
• Handover Access message (uplink)
SDCCH MESSAGES• Request for a SDCCH assignment
• Request for the end of channel assignment
• Order of commutation from SDCCH to TCH
• SMS
Logical Channel Description (1/2)
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FCCH MESSAGES
• no message is sent (all bits 0)
BCCH MESSAGES
• System Information type 1, 2, 2bis,2ter, 3, 4, 7, 8
(idle mode)
SCH MESSAGES• Frame Number
• Base Station Identity Code (BSIC)
AGCH MESSAGES• For dedicated channel assignment:
-frequency number-slot number-frequency hopping description-Timing Advance (1st estimation)-MS identification
PCH MESSAGES
• messages containing a mobileidentity for a call, a short messageor an authentication
RACH MESSAGES• Service request:
- emergency call - answer to an incoming call- outgoing call- short message- call re-establishment- inscription
CBCH MESSAGES• Specific information
(weather, road information
Logical Channel Description (2/2)
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GPRS
CORE
NETWORK
BSCPCUSN
PDCH = Packet Data CHannel
PPCHPAGCHPNCH
PDTCHPACCHPTCCH
PDTCHPACCHPTCCH
PBCCH
PRACH
DL
UL
Packet Common Control
CHannels
Packet Traffic
CHannels
PBCCH
GPRS Channels
79
0 1 2 3 4 21 22 23 24 25 0 1 2 3 4 46 47 48 49 50
26 traffic frames = 120 ms
1 Hyperframe = 2,715,648 frames= 3h 28 min. 53 s 760 ms
0 1 2 3 5 2042 2043 2044 2045 2046 20474
1326 frames
0 1 2 3
46 47 48 49 500 1 3 42
22 23 2524
TS0
TS1
TS2
TS3
TS5
TS6
TS7
TS0
TS1
TS2
TS3
TS4
TS5
TS6
TS7
TS0
TS1
TS2
TS3
TS4
TS5
TS6
TS7
TS4
TS0
TS1
TS2
TS3
TS4
TS5
TS6
TS7
TS0
TS1
TS2
TS3
TS4
TS5
TS6
TS7
Frame4.615 ms
Control channelTraffic channel
51 x 26 traffic frames = 6.12 s
26 x 51 control frames = 6.12 s
Traffic and Control Multiframing
80
81
82
Full Rate - Downlink & Uplink
T : TCH A : SACCH : IDLETi: TCHsub-channel no. i
Ai: SACCHsub-channel no. i
time
26 frames = 120 ms
T0 A0T0 T0 T0 T0 T0 T0 T0 T0 T0 T0 T0T1 T1 T1 T1 T1 T1 T1 T1 T1 T1 T1 T1 A1 time
Half Rate - Downlink & Uplink
T AT T T T T T T T T T TT T T T T T T T T T T T
T
26 frames = 120 ms
Logical Channel Mapping1 - Traffic Channel Combination
83
A : SACCH D : SDCCH : IDLE
51 frames = 235 ms
A1 A2 A3A0D7D6D5D4D3D2D1D0
A5 A6 A7A4D7D6D5D4D3D2D1D0
time
Downlink
51 frames = 235 ms
A5 A6 A7 A0
A4
D7D6D5D4D3D2D1D0
D7D6D5D4D3D2D1D0A1 A2 A3
time
Uplink
AAAA
Logical Channel Mapping2 - Dedicated Signaling Channel Combination
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51 frames = 235.38 ms Downlink
time
51 frames = 235.38 ms
RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR RRRRRRRRRRRRRRRRRR
Uplink
timeB : BCCHS : SCHF : FCCH : IDLE
: PCH /AGCHC R : RACH
BTS MSPhysical Channel
ARFCN (n) TS (s)
FCCHSCH BCCH
PCH/AGCH
Frames repeat continuously
Multiframem+1
Multiframem-1
Multiframe m
C CF SC CFSC CFSC CCBFS FS BFSC
Logical Channel Mapping3 - Common Channel Combination
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A3A2
A1D3D2
D3D2
D1
D1
D0
D0 FSFSFSC CC FSBFS
FSFSFSC CC FSBFS
51 frames = 235 ms
A0
time
Downlink
R R
R R D2
D2
D1
D1
D0
D0A1
A3
A0
A2R
R
R
R
D3
D3
51 frames = 235 ms
time
Uplink
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
A : SACCH D : SDCCH : IDLEB : BCCHS : SCHF : FCCH : AGCH/PCHC R : RACH
Logical Channel Mapping4 - Common Channel Combination
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87
Downlink message
Uplink message
Neighboring BTS(downlink)
Measurement Windows
C CF SC CF SC CF SC CCBF S F S F S
0 1 12 25 0 1 12 25
0 1 10 20 30 40 50 0 1
T AT T T T T T T T T T TT T T T T T T T T T T T T AT T T T T T T T T T TT T T T T T T T T T T T
Mobile activity
Rx Rx Tx Rx Rx Tx Rx Rx Tx(n) (n) (n)
Why 26 and 51 Frames per Multiframe?
