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MAIO Management

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Purpose of MAIO Management

The MAIO Management feature provides increased control

over synthesized frequency hopping to minimize channel

interference within a site. The cells within the site needs tobe synchronized!

This is beneficial in a network with tight re-use of

frequencies, such as 1/1 & 1/3.

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Concepts

Basic Physical Channel (BPC) TS + TDMA frame

Hopping Group (HG) Group of BPC using the same TS

Channel Group (CHGR) A set of frequencies. Possible to

define several CHGR to a cell

Hopping Frequency Set (HFS) Specifies the frequencies which a

CHGR can hop over

Hopping Sequence Number (HSN) Which order to use the frequencies

in the HFS for the CHGR

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Concepts continued

Synchronized cells Cells belonging to the same TG orsynchronized TG:s and equal HSN

or HSN containing the same number

of fq:s Mobile Allocation Index Offset (MAIO)

Transceiver Group (TG)

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TRX

TRX

TRX

TRX

TRX

TRX

CHGR 0. The BCCH

frequency

CHGR 1. The set of

frequencies belonging to these

(8) HGs are called Hopping

Frequency Set (HFS).

CHGR 2.

Each of these groups of BPCs

are defined as a Hopping Group (HG).

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Algorithm

At frequency hopping MAIO values are used (together with the HSN

and the current FN) to point out the frequencies to be used from the

HFS at an instant in time.

Cyclic hopping"pointer" = (MAIO+FN) modulo (number of frequencies in HFS)

Random hopping"pointer" = (MAIO+random value) modulo (number of frequencies in HFS)

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Default MAIO list

The number of MAIO values in the default list are the same as the

number of frequencies in the HFS.

The order of the MAIO values in the default list are arranged in a "first

even then odd MAIO values" manner.

The actual MAIO values to be used for a CHGR depends on the

number of TRXs for the CHGR.

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Example of Default MAIO list

If there are seven frequencies in the HFS, the MAIO list will contain

the values 0-6.

MAIO=0, 2, 4, 6, 1, 3, 5

If three TRXs are used for a CHGR, only the first three MAIO values in

the MAIO list will be used, i.e. 0, 2, 4.

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Cyclic hopping, 3 TRX:s in a cell,

nine frequencies in the HFS. The

current FN is 1.

The first TRX use frequency

number:

(FN+MAIO) mod (# of frequencies

in HFS) = (1+0) mod 9 = 1 (which

will relate the pointer to the second

frequency in the HFS

The next time FN=2 and thepointers will be shifted downwards

one step.

Example

0, 2, 4

Default MAIO list:

HFS

8

76

5

4

3

2

1

0

33

3122

21

17

12

7

4

2

Pos.

4

2

0 TRX1

TRX2

TRX3

FN=1

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Manual MAIO list

A manual MAIO list for a CHGR can be created by specifying up to 32

values for the parameter MAIO.

If the manual MAIO list is too short then random MAIO values will be

added on to the end of the list.

If there is an invalid MAIO value in the manual MAIO list it will be

skipped in favor of the next MAIO value in the list.

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GPRS

MAIO Management can be used on GPRS channels in the same way

as for circuit switched channels. No measures, or concerns have to be

taken.

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Recommendations

On neighbor cells the same frequencies and MAIO values (e.g. the

default list) can be used as long as the cells are unsynchronized.

When using 1/1 reuse in a network it is beneficial to use manual MAIO

planning

In a 1/3 reuse without synchronization, only considerations concerning

adjacent frequencies within a cell has to be taken. The default value

for the parameter MAIO is recommended to be used

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Parameter

name

Default

value

Recommended

value

Value range Unit

MAIO Default - 0-31 or

Default

-

HOP OFF ON OFF, TCH,ON -

HSN - Use the same HSN

for synchronized

co-sited cells

0-63 -

FHOP - SY BB, SY -

COMB - HYB HYB, FLT -