04-LTE Cell Planning-PCI Planning(20140326)

Department: Learning-Service Staff Training RF Team Author/ ID: yuanshaobang(Rayman)/00163462 Version: V1.0(20140324) Version:  V1.0(20140324)

1.PCI concept 2.PSS and SSS Location 3.Rreference signals constrains 4.PCI planning principle 5.PCI planning example



Upon completion of this course, you will be able to: 

Describe the procedure of PCI planning



Plan the PCI in the live network



PCI: Physical Cell ID, is used to generate scrambling code to identify different cells.



It is determined by reading PSS and SSS .



PCI = 3*SSS + PSS

Less Interference

F1

eNB

PRB

PCI specific scrambling

F1

PRB

eNB

Extended CP

0 1 2 3 4

5 PSS (Primary Synchronization Sequence)

Bandwidth

Normal CP

0 1 2 3 4 5 6 62 Subcarriers

72 Subcarriers

Bandwidth SSS (Secondary Synchronization Sequence) Slots

0

1

2

3

4

5

6

7

8

9 10 11 12 13 14 15 16 17 18 19

Radio Frame Repeated in slots 0 and 10

Extended CP

0

1

2

3

4

5 0

1

2

3

4

5

Bandwidth

0 1 2 3 4 5 6 0 1 2 3 4 5 6

Normal CP

Bandwidth

Slots

0

1

2

3

4

5

6

7

8

9 10 11 12 13 14 15 16 17 18 19

Radio Frame



PCI determines Reference Signal position in frequency domain.



It is advised to distribute PCIs in adjacent cells such that Reference Signals does not occupy same subcarrier position.



Therefore cell can have up to 5 different neighbors without interfering in frequency domain, i.e., Modulo6 problem.

Physical Cell ID = 0 R R

eNB

R R

R

RS position is based on Physical Cell ID (Physical Cell ID mod 6)

Physical Cell ID = 8 R R

R R

R

R R

R

R

R

R

eNB



However LTE is usually implemented in 2x2, where the other antenna reference signals are positioned in between first antenna, therefore Modulo6, becomes Modulo3 problem.

x

R

x

R

R

x

R

x

R

x

R

x

x

R

x

R

x

R

x

R

R

x

R

x

R

x

R

x

x

R

x

R

Antenna Port 0

Antenna Port 1

R

RS symbol for antenna port 0

RS symbol for antenna port 1 R RS symbol for antenna port 2 R

R

RS symbol for antenna port 3

x x

R

x x

R

R x

x

R x

x

x x

x

x R

x

x R

x

x x

x

R x

x

R x

x

x x

R

x x

R

x R

x

x x

x

x x

x

x R

x

x x

R

x x

R

R x

x

R x

x

x x

x

x R

x

x R

x

x x

x

R x

x

R x

x

x x

R

x x

R

x R

x

x x

x

x x

x

x R

x

collisionfree

confusionfree

2 1 0

3 sectors site

1

4 sectors site

2

2

0