b7_rnp_extension_frequency_hopping_ed01_modified

Mobile Radio Network Planning 1All rights reserved © 2003, Alcatel

Frequency Planning of Hopping Networks

Fractional Reuse

Mobile Radio Network Planning

2

RNP Extension: Frequency Hopping

All rights reserved © 2003, Alcatel

Reuse Cluster Size Definition for FH The classical definition of the Reuse Cluster Size is:

The definition of the Reuse Cluster Size for RFH conditions is:

cellperTRXofamountAverageBandwidthARCS

cellpersFrequencieofamountAverageBandwidthFARCS

FARCS = Fractional Average Reuse Cluster Size


3



Examples for ARCS ARCS

27 frequencies for TCH TRXs 3 TCH TRXs in average per

cell

93

27/#

cellTRX

BARCS Example: Group planning with 9 frequency groups, 3 frequencies each

A1

A3

A2 B1 B2

B3

A1 A2

A3

B2

B3

B1

C2

C3

C1B2B1

B3

A1 A2

A3

REUSE 3*3


4



Examples of FARCS (1) FARCS

27 frequencies for TCH TRXs

3 hopping groups with 9 frequencies each

1 hopping group per cell

3927

/#

cellfBFARCS

REUSE 1*3

Example:3 frequency groups, 9 frequencies each

A

C

B A B

C

A B

C

B

C

A

B

C

ABA

C

A B

C


5



Examples of FARCS (2) FARCS

27 frequencies for TCH TRXs

1 hopping group with 27 frequencies

same hopping group on each cell

12727

/#

cellfBFARCS

REUSE 1*1

Example:1 frequency group including all 27 frequencies

A

A

A A A

A

A A

A

A

A

A

A

A

AAA

A

A A

A


Frequency Planning of Hopping Networks

Creating Hopping Groups


7



The GSM Hopping Sequence Generator Abbreviations

MA Mobile Allocation MAI Mobile Allocation Index MAIO Mobile Allocation Index Offset FHS Frequency Hopping Sequence HSN Hopping Sequence Number T1, T1R, T2, T3 GSM internal timers FN Frame Number


8



MAMAI ARFCN

123

0

4

... ...

2512

7

6

MA - Mobile Allocation The MA is the look up table

that is giving the relation between the different MAI numbers and the corresponding ARFCN. Range:

The look up table has N lines. N is the number of frequencies used in the hopping sequence (hopping group)


9



MAI - Mobile Allocation Index The MAI is an index number, which allows to determine the

correct line in the MA look up table to find the corresponding ARFCN.

Range: 0 .. N-1

Note: N is the number of frequencies used in the hopping sequence.


10



MAIO - Mobile Allocation Index Offset The MAIO is selectable for each timeslot and each TRX

separately The MAIO is constant on the TRX but it changes between the

FU Due to the fact, that normally for each timeslot within one

TRX the same FHS is used, there is no need to change the MAIO from timeslot to timeslot. Therefore the MAIO is constant on the TRX.

It is a number that is added to the calculated MAI to avoid intra-site collisions due to co or adjacent channel usage.

Range: 0 .. N-1


11



MAIO - BBH Example (1)

TS 0 TS 1 TS 2 TS 3 TS 4 TS 4 TS 5 TS 6 TS 7FU 1 BCCH TCH TCH TCH TCH TCH TCH TCH TCHfhs_id, maio freq 1, 0 1, 0 1, 0 1, 0 1, 0 1, 0 1, 0 1, 0FU 2 TCH SD/8 TCH TCH TCH TCH TCH TCH TCHfhs_id, maio 2, 0 1, 1 1, 1 1, 1 1, 1 1, 1 1, 1 1, 1 1, 1FU 3 TCH TCH TCH TCH TCH TCH TCH TCH TCHfhs_id, maio 2, 1 1, 2 1, 2 1, 2 1, 2 1, 2 1, 2 1, 2 1, 2FU 4 TCH TCH TCH TCH TCH TCH TCH TCH TCHfhs_id, maio 2, 2 1, 3 1, 3 1, 3 1, 3 1, 3 1, 3 1, 3 1, 3


12



MAMAI ARFCN

123

0F2F3F4

F1E.g. MAI = 1 calculated

MAIO=2

F4 is used

MAIO - Example (2) E.g. a TRX has the MAIO 2 Frequencies used on this TRX: f1, f2, f3 ,f4 The frequency hopping generator creates the MAI sequence

3,0,1,2,1,1,3,0,2,… The hopping sequence will be:

f2, f3, f4,f1,f4,f4,f2,f3,f1,...


13



HSN - Hopping Sequence Number The HSN is one of 4 input parameters to the GSM hopping

sequence generator algorithm (see GSM Rec: 05.02). Range: 0 .. 63 HSN = 0 means cyclic hopping! The values 1 to 63 are so called Pseudo Random Hopping

Sequence Numbers. Their usage forces the hopping sequence generator algorithm to determine MAIs randomly. Due to the fact, that only the GSM internal timers T1R, T2 and T3 are additional input to this algorithm, their period is also the period of the hopping sequence


14



T1, T1R, T2, T3 - GSM internal timers Ranges of the timers:

T1: 0 .. 2047 T1R: 0 .. 63 (T1R = T1 modulo 64) T2: 0 .. 25 T3: 0 .. 50

T2 and T3 are triggered every 8 timeslots (1 TDMA Frame). When both timers switch back to 0, T1 (and T1R) is triggered (that is every 26*51= 1326 TDMA Frames).

In the GSM hopping sequence algorithm the timers T1R, T2 and T3 are used. This is leading to a period of 64*26*51-1 = 84863 for the MAI sequence (hopping sequence)


15



Note: Duration of one TS 577 µs

FN - Frame Number It is incremented after every TDMA frame (8 timeslots) At each FN increment, timers T1, T1R, T2, T3 are impacted,

however only T1R, T2, T3 determine the periodicity of the MAI sequence (hopping sequence)

FN periodicity is 26*51*2048-1 = 2 715 647 TDMA frames Each frame has a duration of apporx. 4.62 ms The absolute time from FN 0 to next time FN 0 is

accordingly:2 715 647 * (8*577 µs) = 3h 28min 53 s


16



Hopping Sequence Generation - Diagram With the before shown

parameters, the used absolute frequency can be determined

MA MAIO HSN T1 T2 T3

Algorithm specified inGSM Rec. 05.02

ARFCN = MA(MAI)Press fordemonstration


17



The Period of the Hopping Sequence Timer T1R is only increased, when T2 and T3 switch back to

zero at the same time (every 1326 TDMA frames)! The total period of the 3 timers T1R, T2, T3 (=duration of

FHS): 64*26*51-1 = 84863 TDMA frames 6min 32sec

This means, that even if we select the same HSN on two different (not synchronised I.e no common master clock) sites, they have a probability of

1/84863 = 1.18*10-6to use the same frame number.If they have different frame numbers, the order of the used hopping frequencies is uncorrelated


18



New understanding of reuse A reuse of A X B means, that A sites belong to the same

reuse cluster and B frequency groups are used on this site.

A

AA

A

AA

A

CB

A

CB

Re-use 1x3 Re-use 1x1


19



Co-cell / co-site constraints max RF load Co-cell constraint 2 channels spacing (ETSI recommends

3, but with Alcatel EVOLIUM capabilities this value can be set to 2)

Co-site constraint 2 channels spacing As on the same site the minimum distance between two

frequencies is 2, only every second frequency of a band of consecutive frequencies can be used

This is leading to a effective usage of the spectrum resources of maximum 50%

These 50% are the so called maximum RF load on the site


20



Max RF Load The max RF load within a cell can be calculated according the following formula:

This maximum RF load is only achieved, if all TRXs within the cell are fully loaded! If the TRXs are only fractional loaded, the effective RF load is much lower!

CellsFrequencieCellTRXloadRF

/#/#max


21



%7.16122.max loadRF

%5042.max loadRF

Max RF Load - Examples 3 sector site, 12 hopping frequencies, 2 hopping TRX per sector

1*1 reuse:

1*3 reuse:

These values (16.7% and 50%) are the theoretical maximum achivable RF loads for the two cases. This is due to the fact, that a consecutive frequency band is assumed and thus due to inter cell constraint of 2 channels spacing only every second frequency can be used at the same time


22



Inter site constraints The maximum RF load is just a theoretical value, up to

which we can avoid violating the co-cell and co-site constraints

The real RF load of a cell (e.g. the traffic in Erlang handled by the hopping carriers) is the real indicator for the interferer potential of the cell

With increasing number of used hopping TS, the probability of having a collission with a used TS of another cell using the same hopping frequencies is increasing


23



Traffic / Interference relation - Examples Which scenario interferes most to your communication (yellow)?

Scenario 1 Scenario 2 Scenario 3

TRX1

TRX2

TRX3

TRX4

TS 0 1 2 3 4 5 6 7TRX1

TRX2

TRX3

TRX4

TS 0 1 2 3 4 5 6 7TRX1

TRX2

TRX3

TRX4

TS 0 1 2 3 4 5 6 7

TRX1

TRX2

TRX3

TRX4

TS 0 1 2 3 4 5 6 7TRX1

TRX2

TRX3

TRX4

TS 0 1 2 3 4 5 6 7TRX1

TRX2

TRX3

TRX4

TS 0 1 2 3 4 5 6 7

Assumptions: Cells not syncronized, cells using same hopping frequencies, BCCH not included

Inte

rfer

erSe

rver


24



Creating Hopping sequences The following slides show, how new frequency hopping

groups can be generated and how the MAIO is assigned to the different TRXs within the cell

Keep in mind the two GSM constraints 2 channels spacing between the frequencies on air at

the same time within one cell (only Alcatel EVOLIUM equipment)

2 channels spacing between the frequencies on air at the same time within one site

Assumptions: 12 consecutive frequencies available (1..12)

excluding BCCH frequencies


25



Fractional Reuse 1*2,

1*3, 1*x


26



1*3 reuse (1) Before we create new groups, we

have to keep two things in mind: The RF-load of 50% is not

possible with consecutive frequencies in the FHS

50% RF-load is only possible when all odd or all even frequencies are on air at the same time same amount of odd and even frequencies in each group

1 4 7 10

2 5 8 11

3 6 9 12

Cell A

Cell B

Cell C

Group A: 1,4,7,10Group B: 2,5,8,11Group C: 3,6,9,12


27



1*3 reuse (2) To avoid violating the GSM constarints, MAIOs have to be

defined for each TRX of the site.

1 4 7 10 1 4 7

2 5 8 11 2 5 8

3 6 9 12 3 6 9

Cell A

Cell B

Cell C

MAI = 0

….

….

….

Frequency used by TRX 1

Frequency used by TRX 2

MAIO settings:

Group A: 0,2

Group B: 1,3

Group C: 0,2


28



1*3 reuse (3) In a hopping group with 4 frequencies, the MAIs 0 to 3 are

possible to be generated by the hopping sequence generator

1 4 7 10 1 4 7

2 5 8 11 2 5 8

3 6 9 12 3 6 9

Cell A

Cell B

Cell C

1 4 7 10 1 4 7

2 5 8 11 2 5 8

3 6 9 12 3 6 9

Cell A

Cell B

Cell C

1 4 7 10 1 4 7

2 5 8 11 2 5 8

3 6 9 12 3 6 9

Cell A

Cell B

Cell C

1 4 7 10 1 4 7

2 5 8 11 2 5 8

3 6 9 12 3 6 9

Cell A

Cell B

Cell C

MAI = 0

MAI = 3MAI = 1

MAI = 2

Assumption:MAIOs are as defined before

Group A: 0,2Group B: 1,3Group C: 0,2


29



1*3 reuse (4) For each frequency group we have an own MA table With the group allocation from before, we get:

MAI ARFCN

MA - Group B

1

2

3

2

5

8

11

0

MAI ARFCN

MA - Group A

1

2

3

1

4

7

10

0

MAI ARFCN

MA - Group C

1

2

3

3

6

9

12

0


30



1*2 reuse (1) On a two sector site we may have only 2 frequency groups

and therefore only an 1*2 reuse. In a first step we allocate the frequencies according to the

allocation scheme known from the 1*3 reuse

Group A

Group B 2 4 6 8 10 12

1 3 5 7 9 11

Problem: For max. possible RF load, all odd or even must be on air at the same time. This is not possible in this case, as all odd frequencies are in group A and all even in group B


31



1*2 reuse (2) To have an equal distribution between odd and even

frequencies within one frequency group, we change every second frequency

Group A

Group B 2 4 6 8 10 12

1 3 5 7 9 11 Group A

Group B 2 3 6 7 10 11

1 4 5 8 9 12

To be done: MAIO assignment!


32



1*2 reuse (3) To assign MAIOs we assume the FN 0, and circle as many

frequencies as TRXs are using this group. The circeled frequencies must fulfil the GSM intra site and intra cell constraint

1 4 5 8

2 3 6 7

Cell A

Cell B

9

10 11

12MAIO TRX 1

MAIO TRX 2

MAIO TRX 3


33



1*4 - Exercise The frequencies 1..24 are available (excluding BCCH freq.) 4 sectors on the site 3 TRXs are hopping in each cell Cells are syncronized in terms of FN

Create Hopping Groups and assign MAIOs!


34



Fractional Reuse 1*1


35



Reuse 1*1 - 3 sector site In the reuse 1 case, we use all available frequencies (1..12)

on each cell of the site Intra site collisions are only avoided by the MAIO

assignment

1 2 3 4

1 2 3 4

Cell A

Cell B

5

5 6

6 7 8 9 10 11 12

7 8 9 10 11 12

1 2 3 4Cell C 5 6 7 8 9 10 11 12

... .... ... ..........

..........................

MAIO of TRX 1

MAIO of TRX 2


36



Reuse 1*1 - 2 sector site On a 2 sector site with 12 frequencies of course 3 TRXs per

cell are possible

61 2 3 4

1 2 3 4

5

5 6

7 8 9 10 11 12

7 8 9 10 11 12

Cell A

Cell B

MAIO of TRX 1

MAIO of TRX 2

MAIO of TRX 3


37



Reuse 1*1 - Exercise The frequencies 1..24 are available 4 sectors on the site 4 TRXs are hopping in each cell Cells are syncronized in terms of FN

Create Hopping Groups and assign MAIOs!


38



Summary: 1*2/1*3/1*4/…1

2

Cell A

Cell B

.......

.......

.......

.......

.......

3

...

Cell C

Cell ...

1 4

2 3

Cell A

Cell B

.......

.......

.......

.......

.......

1

2

Cell A

Cell B

3

...

Cell C

Cell ...

....... .......

.......

.......

.......

.......

MAIO TRX 1

MAIO TRX 2

MAIO TRX 3

MAIO0 2 3 4 51

Cell A

Cell B

Cell C

Cell D

.......

TRX

1

TRX

2

TRX

3

TRX

....

0

1

0

1

2

3

2

3

4

5

4

............ ..... .......

..... .......

.......

.......

.......

Only necessary, if the number of frequency

groups id even

“Rotate” the frequencies through the

cells

Assign MAIOs

according to the

standard scheme for Reuse 1*X


39



Summary: 1*11 2 3 4

1 2 3 4

Cell A

Cell B

5

5 6

6 7 8 9 10 11 12

7 8 9 10 11 12

1 2 3 4Cell C 5 6 7 8 9 10 11 12

... .... ... ..........

..........................

MAIO of TRX 1

MAIO of TRX 2

Cell A

Cell B

Cell C

.....

.......

TRX

1

TRX

2

TRX

3

TRX

....

0

2

4

x+2

x+4

2x+4

....

....

2x+2

.......

..... .......

..... .......

.......

.......

.......

x

....

....

“Rotate” the MAIOs

through the cells

Standard MAIO assignment for

Reuse 1*1


40



FH parameter relation to Hardware - 1*3

FN(T1R, T2, T3)(0 … 84863)

HSN(0 … 63)

Frequency HoppingSequence A

(e.g. 1,4,7,10)

Sector 1

Frequency HoppingSequence B

(e.g. 2,5,8,11)

Sector 2

Frequency HoppingSequence C

(e.g. 3,6,9,12)

Sector 3

MAIO (e.g. 2)Hopping TRX 2

Site Cells TRXsMAIO (e.g. 0)Hopping TRX 1






41



FH parameter relation to Hardware - 1*1

FN(T1R, T2, T3)(0 … 84864)

HSN(0 … 63)

Sector 1

Frequency HoppingSequence

(e.g. 1,2,3,4,5,6,7,8,10,11,12)

Sector 2

Sector 3

Site Cells TRXs








42



Alcatel BTS - Hopping concepts A910 (M4M) - Evolium Micro BTS

RFH possible for each non BCCH TRX(max. 4 TRX within one sector)

A9110-E (M5M) Micro Base Station BBH RFH for each non BCCH TRX

A9100 - Evolium Macro BTS BBH RFH for each non BCCH TRX


43



Implementation of Frequency Plan to the OMC-R Directly using OMC-R

Frequencies are implemented manually in the OMC-R Used for small networks

Using External Tools A955 RNO or Excel edit of PRC files (for small changes) Particularly A955 RNP offers its A955 PRC Generator Module to

upload the frequency plan to the OMC-R (for massive changes)Number of Cells Time Estimation using

OMC-RTime Estimation using

external tool10 1h22' 1h22'100 4h24' 4h26'500 17h50' 17h58'

1000 34h38' 34h55'2000 68h14' 68h49'


RNP Extension: B7 Frequency Hopping

Frequency Hopping Parameters


45



BSS and CAE parameters In the hopping case, RXQUAL does not reflect the real

quality in the network as explained before To overcome this problem, Offsets are applied to RXQUAL

dedendent parameters Offset_Hopping_PC influences

L_RXQUAL_UL_P L_RXQUAL_DL_P

Offset_Hopping_HO influences L_RXQUAL_UL_H L_RXQUAL_DL_H


46



Default Parameters for SFH Find hereafter the parameters which are different within

hopping networks

Offset_Hopping_PC = 1.0

Offset_Hopping_HO = 1.0

HO_INTRACELL_ALLOWED = DISABLED

Note: Resolution of Offset_Hopping_XX is 0.1 since B6.2 ( 1 in B5.1 )


47



Quality indicator for FH (1)The RXQUAL calculation takes only the BER before de-

interleaving into account The benefit of FH is not visible in RXQUAL The higher probability to get into a fading notch

(but for a shorter time) is leading to a worse RXQUAL then without hopping, except the non hopping frequency would be in a fading notch at this location

FER - Frame Erasure Rate is counted after de-interleaving takes higher error correction possibilities due to FH

into account


48



Quality indicator for FH (2) Principle of quality indicator calculation within the mobile

DEMOD DECODER

ENCODER

Frame Erasure Decision VoiceDecoder

RXQUAL Frame Erasure RateFER

DeinterleaveError

correct.

Inside the mobile stationAir

-


49



Influence of FH on RXQUAL-1

10

-106

-102

RXQUAL_DL = f (RXLEV_DL)

0

1

2

3

4

5

6

7-9

8

-94

-90

-86

-82

-78

-74

-70

-66

-62

-58

-54

-50

Without Hopping

With Hopping

RXQU

AL

RXLEV [dBm]

Subjective speech quality is good with RXQUAL=5

approximately:

RXQUAL(FH)=

RXQUAL(no FH) + 1

Offset_Hopping_PC and Offset_Hopping_HO are introduced for correcting this “error”.Resolution since B7.2: 0.1Min value : 0; Max value : 7


50



FH implementation via OMC-R 1353-RA (1) One of the tasks of the OMC-R is the management of

relationships between a cell and its neighbouring cells in the network

In the OMC-R it is done by the logical configuration management

For example, it enables you to: Radio configuration including frequency allocation,

frequency hopping schemes, TRX and logical channel configuration

PC/HO parameters Import/Export…


51



FH impl. via OMC-R 1353-RA (2) B7.2 TRX configuration

Selecting hopping mode and MAIO


52



FH impl. via OMC-R 1353-RA (3) B7.2 Frequency Allocation and FHS definition

Selecting HSNSelecting cell hopping type


53



What about Your network? How to start? Frequency Band and its subdivision Special Cells (micro-cells, concentric cells…) Hopping useful?BBH or RFH? Problems (RF load, interference…)/Solutions

Open Discussion

b7_rnp_extension_frequency_hopping_ed01_modified

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