microsoft power point - 6 omf007001 frequency planning issue1
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Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Frequency Planning
Page2Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Contents
1. Frequency Planning
2. Tight Frequency Reuse
3. Frequency Hopping
Page3Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Content of Frequency Planning
� Frequency resource of GSM system
� Concept of frequency reuse
� Requirement for interference and carrier-to-interference
ratio
� 4*3 frequency reuse
Page4Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
GSM 900 :
GSM 1800 :
1710 1785 1805 1880
Duplex distance : 95 MHz
890 915 935 960
Duplex distance : 45 MHz
Frequency Resource of GSM System
Page5Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Frequency Band Configuration
� GSM900:
� BTS receiver (uplink ): f1 (n) =890.2+ (n-1)*0.2 MHz
� BTS transmitter (downlink ): f2 (n) =f1 (n) +45 MHz
� GSM1800:
� BTS receiver (uplink ): f1 (n) =1710.2 + (n-512) * 0.2 MHz
� BTS transmitter (downlink ): f2 (n) =f1 (n) +95 MHz
Page6Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
{fi,fj..fk}
{fi,fj..fk} {fi,fj..fk} {fi,fj..fk}.. ..
Macro-cell system
d
Micro-cell system
Concept of Frequency Reuse
Page7Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
The Reason of Frequency Reuse
� Frequency resource is limited. If there is 8MHz frequency
resource, 8 MHz = 40 channels * 8 timeslots = 320
� Max. 320 users can access the network at the same time.
� If every frequency is reused N times
� Max. 320*N uses can access the network at the same time.
Page8Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Requirement for Interference and Carrier-to-Interference Ratio
All useful signals carrier
All useless signals interference=
GSM standard: C / I >= 9 dB
In practical projects: C / I >= 12dB
Useful signal Noise from environment
Other signals
C/I =
Page9Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Requirement for Interference and Carrier-to-Interference Ratio
All useful signals carrier
All useless signals interference=
GSM standard: C / I >= 9 dB
In practical projects: C / I >= 12dB
Useful signal Noise from environment
Other signals
C/I =
Page10Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Looser reuse
Higher frequency reuse
efficiency, but interference
is serious. More technique
Is needed.
Tighter reuse
0 12 20
Little interference, but frequency
reuse efficiency is low.
Reuse Density
� Reuse density is the number of cells in a basic reuse cluster.
� 4*3:12
� n*m:n*m
� n: BTS number in a basic reuse cluster
� m: Frequency group number in a BTS
Page11Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
4*3 Frequency Reuse
A1
C1
B1
D1A2
A3B2
B3
C2
C3D2
D3
A1
C1
B1
D1A2
A3B2
B3
C2
C3D2
D3
A1
C1
B1
D1A2
A3B2
B3
C2
C3D2
D3 A1
C1
B1
D1A2
A3B2
B3
C2
C3D2
D3
A1
C1
B1
D1A2
A3B2
B3
C2
C3D2
D3
A1
C1
B1
D1A2
A3B2
B3
C2
C3D2
D3
Page12Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
A1 B1 C1 D1 A2 B2 C2 D2 A3 B3 C3 D3
34 35 36 37 38 39
40 41 42 43 44 45 46 47 48 49 50 51
52 53 54 55 56 57 58 59 60 61 62 63
64 65 66 67 68 69 70 71 72 73 74 75
76 77 78 79 80 81 82 83 84 85 86 87
88 89 90 91 92 93 94 95
Illustration of Frequency Allocation of 4*3 Frequency Reuse
Page13Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Contents
1. Frequency Planning
2. Tight frequency Reuse
3. Frequency Hopping
Page14Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Tight Frequency Reuse Technology
� Multi-layer reuse pattern
� Underlaid and overlaid cell
� 1*3 or 1*1
Page15Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Multi-layer Reuse Pattern
Page16Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
BCCH: n1
TCH1: n2
TCH2: n3
…
TCHm-1: nm
n1 ≥n2≥n3 ≥n4 ≥...... ≥ nm
And n1+n2+...+nm=n
Multi-layer Reuse Pattern
Page17Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Multi-layer Reuse Pattern Frequency Allocation
� Suppose that the available frequency carrier is 10MHZ,
channel number is 46~94, the Multi-layer reuse pattern
should be:
RC Type Allocated
Frequencies
Number of Available
Frequencies
BCCH 46~57 12
TCH1 58~66 9
TCH2 67~74 8
TCH3 75~82 8
TCH4 83~88 6
TCH5 89~94 6
Page18Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
BCCH TCH1 TCH2 TCH3 TCH4
{f1,f3,f5...f23}
{f1,f2,f3,f4,f5...f40}
{f2,f4..f22,f24...f40}
Multi-layer Reuse Pattern Frequency Allocation
Page19Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
� Capacity increase when reuse density is multiplied:
� Supposing there are 300 cells
� Bandwidth: 8 MHz (40 frequency)
� Normal 4*3 reuse: reuse density=12
� Network capacity = 40/12 * 300 = 1000 TRX
� Multiple reuse:
BCCH layer: re-use =14, (14 frq.)
Normal TCH layer: re-use =10, (20 frq.)
Aggressive TCH layer: re-use = 6, (6 frq.)
� Network capacity = (1 +2 +1)* 300 = 1200 TRX
Advantages of Multi-layer Reuse Pattern
Page20Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
� Capacity increases when reuse density is multiplied:
� Supposing there are 300 cells
� Bandwidth: 8 MHz (40 frequency)
� Normal 4*3 reuse: reuse density=12
� Network capacity = 40/12 * 300 = 1000 TRX
� Multiple reuse:
BCCH layer: re-use =14, (14 frq.)
Normal TCH layer: re-use =10, (20 frq.)
Aggressive TCH layer: re-use = 6, (6 frq.)
� Network capacity = (1 +2 +1)* 300 = 1200 TRX
Advantages of Multi-layer Reuse Pattern
Page21Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
The inner circle covers a smaller area, and the frequency can
be reused more tightly.
Underlaid/Overlaid Frequency Allocation
Overlaid-cell
Underlaid-cell
Page22Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Overlaid/Underlaid Frequency Configuration
Super fn
Regular fm Regular fm Regular fm
Super fn
BCCH 15f Regular 24f Super 12f
BCCH TRX reuse density: 15
Regular TCH TRX reuse density: 12
Super TCH TRX reuse density: 6
Super fn
Page23Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
BCCH14+TCH36::::
1BCCH+3TCH
1BCCH+3TCH 1BCCH+3TCH
1BCCH+12’TCH
1BCCH+12’TCH 1BCCH+12’TCH
4*3
1*3
1*3 or 1*1Reuse Patterns
1BCCH+36’TCH
1BCCH+36’TCH 1BCCH+36’TCH
1*1
Page24Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
TRX1 TRX2 ... TRX7
TRX8 TRX9... TRX14 TRX15 TRX16...TRX21
TRX1 TRX2 ... TRX7
TRX8 TRX9... TRX14 TRX15 TRX16...TRX21
The red items are BCCH RCs
Illustration of 1*3 or 1*1 TCH Frequency Allocation
Page25Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Frequency Planning Principle
� There should be no co-channel frequency carriers in one BTS.
� The frequency separation between BCCH and TCH in the same cell should
be not less than 400K.
� When frequency hopping is not used, the separation of TCH in the same cell
should be not less than 400K.
� In non-1*3 reuse mode, co-channel should be avoided between the
immediately neighbor BTS.
� Neighbor BTS should not have co-channels facing each other directly.
� Normally, with 1*3 reuse, the number of the hopping frequencies should be
not less than twice of the number of frequency hopping TRX in the same cell.
� Pay close attention to co-channel reuse, avoiding the situation that the same
BCCH has the same BSIC in adjacent area.
Page26Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
.
Example of Frequency Planning� An example network in a specific place, BTS are densely
located. The topography is plain. The maximum BTS
configuration is S3/3/2
� Initial planning:
Page27Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Example of Frequency Planning
� Final frequency planning:
Page28Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Example of 1*3 Frequency Reuse
� Suppose 900 band: 96~124
� BTS configuration: S3/3/3
� BCCH layer: 96~109 reuse pattern: 4*3
� TCH layer: 110~124 reuse pattern: 1*3
Page29Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Group 1 (MA1): 110 111 112 113 114 Cell1
Group 2 (MA2): 115 116 117 118 119 Cell2
Group 3 (MA3): 120 121 122 123 124 Cell3
TCH Consecutive Allocation Scheme
Page30Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
TCH Interval Allocation Scheme
Group 1 (MA1): 110 113 116 119 122 Cell1
Group 2 (MA2): 111 114 117 120 123 Cell2
Group 3 (MA3): 112 115 118 121 124 Cell3
Page31Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Comparison Between Multi-layer Reuse and 1*3� For Multi-layer reuse pattern, either Base band hopping or RF hopping
can be used. But for 1x3 reuse, only RF hopping can be used.
� The frequency planning for the 1x3 mode is simple and it is easy to plan
the frequency for new added BTS.
� 1x3 mode requires a rather regular BTS location distribution.
� For the cells with fixed number of TRX, when the traffic is heavy, the 1x3
provides higher service quality than that of Multi-layer reuse pattern.
� TRX can be easily added to the 1x3 network, but TRX number of hopping
should not exceed the product of the allocated hopping frequency number
and the max RF load ratio.
� BCCH of Multi-layer reuse pattern can take part in the frequency hopping,
while BCCH in 1x3 mode can not.
Page32Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Contents
1. Frequency Planning
2. Tight Frequency Reuse
3. Frequency Hopping
Page33Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Content of Frequency Hopping
� Class of hopping
� Advantages of hopping
� Parameter of hopping
� Collocation of hopping data
Page34Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Frequency Hopping
Page35Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Advantages of Hopping
� Get an agreeable radio environment.
� Provide a similar communication quality for every user.
� Tighter reuse patterns are possible to be used for larger
capacity.
Page36Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Smoothen the rapid fading (Rayleigh fading)
Frequency Diversity of Hopping
Page37Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Smoothen and average the interference
Interference Diversity of Hopping
Page38Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Class of Hopping
� Hopping can be implemented in two ways
� Base-band hopping
� RF hopping
� Class according to the min hopping time unit
� Timeslot hopping
� Frame hopping
Page39Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Base Band Hopping Principle
FH bus
Page40Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
RF Hopping Principle
Page41Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Class of Hopping
� Frame hopping
� Frequency changes every TDMA frame. The different channel
of one TRX uses the same MAIO.
� Timeslot hopping
� Frequency changes every timeslot. The different channel of
one TRX uses the different MAIO.
Page42Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Hopping Parameters
� All the parameters which are related to hopping are
configured in cell/configure Hopping data
� Hopping mode: the mode used by the BTS system,
including three options: not hopping, base band
hopping and RF hopping.
� MA (Mobile Allocation Set): the set of available RF
bands when hopping, containing at most 64 frequency
carriers. The frequency being used must be those of
the available frequency
Page43Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Hopping Parameters
� HSN:hopping sequence number(0~63)
� HSN=0:cycle hopping.
� HSN≠0:random hopping. Every sequence number
corresponds a pseudo random sequence.
Page44Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Hopping Parameters
� MAIO (Mobile Allocation Index Offset): used to define the
initial frequency of the hopping.
� Be careful to configure the MAIO of same timeslot in all
channels, otherwise interference occurs.
� At the air interface, the frequency used on a specific burst is
an element in MA set. MAI is used for indication, referring to
a specific element in the MA set.
� MAI is the function of TDMA FN, HSN and MAIO.
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