signal strength coverage aspects-r10

Commercial in Confidence

EAB/RNG-03:0028 Uen Rev A Signal Strength Coverage Aspects2003-04-03 1

Signal Strength Coverage Aspects



Purpose

This presentation explains the impact on coverage fordifferent hardware and feature choices. Alsodependencies between hardware and features isdescribed.

The presentation targets Technical managers.



Coverage definition

In this presentation Coverage is defined as the area where the signal strength is higher than the sensitivity of the receivers both uplink and downlink.



Factors affecting Coverage

• Signal strength design targets

• Hardware

• Features



Signal strength design targetsHardwareFeaturesSignal strength design targets

• Indoor coverage– It is important to understand that indoor coverage often limits the

coverage of the cell. • Antenna height

– A higher positioned antenna will increase the cell coverage at the cost of possible unwanted coverage. This is not always true for indoor coverage.



Signal strength design targetsHardwareFeaturesHardware

Hardware Affected link• RBS type (Uplink & Downlink)• CDU type (Downlink)• Tower Mounted Amplifier (Uplink)• Antenna choice (Uplink & Downlink)



Signal strength design targetsHardwareFeaturesRBS and CDU type

• The maximum output power and thereby the downlink coverage will depend on the RBS and CDU chosen.

RBS hardware choices• RBS 2102/2202 vs. RBS 2106/2206• Filter Combiner vs. Hybrid Combiner



Signal strength design targetsHardwareFeaturesRBS2102/2202 vs. RBS2102/2206

Compared to 2102/2202, the 2106/2206 have:

– Improved sensitivity

– Higher output power

– Higher capacity



Signal strength design targetsHardwareFeaturesFilter vs. Hybrid combiner

Hybrid Combiner (CDU-C+ and -G)+ Supports Software Power Boost + CDU-G supports TCC+ Supports both synthesizer and

baseband frequency hopping

- More antennas needed for high capacity sites.

Filter combiner ( CDU-D and -F)+ Less loss compared with hybrid

(0.5 - 1dB).+ Fewer antennas for high

capacity sites.

- Only baseband frequency hopping supported

- Harder combiner spacing requirements.



Signal strength design targetsHardwareFeaturesTower Mounted Amplifier (TMA)

• TMA improves the radio uplink performance.• By using TMA the BTS Sensitivity is increased up to 1.5

dB and the feeder loss on the uplink is neutralized.

• Requirement : Extra HW needed

Down link

Up link

Extra upExtra up--link budget link budget added by TMA!added by TMA!



Signal strength design targetsHardwareFeaturesAntenna Type

• The cell coverage is to a large extent impacted by the antenna gain.

• Dual system or dual band antenna requires combiners which will decrease the coverage.

• A high gain antenna will either have a large physical size or have a smaller antenna pattern compared to low gain antennas.



Signal strength design targetsHardwareFeaturesFeatures

• Features increasing coverage- This type of features will increase the physically covered area.

Low C/I

Coverage limit

Traffic limited by C/I

- This type of features will increase the usable covered area.

• Features improving C/I robustness



Signal strength design targetsHardwareFeaturesFeatures increasing coverage

Feature Affected link Released• Transmitter Coherent Combining (Downlink) BSS R9.1• Software Power Boost (Downlink) before BSS R8• Rx Diversity (Uplink) before BSS R8



Signal strength design targetsHardwareFeaturesTransmitter Coherent Combining

(TCC) • TCC improves the downlink

performance for RBS 2106/2206.

• Two TXs are connected coherently to the same antenna through a hybrid combiner.

• When the RBS is configured for TCC the downlink gain, compared to a TX connected without hybrid combiner, is 2.5 dB.

Transmitter TransmitterHybridComb.

dTRU TX1 TX2

TX1 + TX2

• 2 carrier per CDU-G is possible with TCC.



Signal strength design targetsHardwareFeaturesSoftware Power Boost (SWPB)

• SWPB improves the downlink performance.

• Two transmitters connected to different antennas are then transmitting with maximum power the same signal on the same frequency. One of the transmitters has its bursts forwarded in time two bits compared to the other.

• The two signals will improve the MS receiver signal processing, resulting in a downlink gain of 3-5 dB.

• SWPB only allows 1 carrier per CDU.

Transmitter Transmitter

TX1 TX2

Antenna A Antenna B



Signal strength design targetsHardwareFeaturesRX Diversity

• The RX diversity function will improve the uplink sensitivity by 3 to 4.5 dB.

• It is achieved by having two antennas, and in this way take advantage of two or more receiver (RX) paths. Based on the two received signals, the equalizer in the receiverwill create a new signal with higher quality.

• Requirement : At least 2 RX antennas or one cross polarized antenna per cell.



Signal strength design targetsHardwareFeaturesFeatures improving C/I robustness

Feature Affected link Released• Interference Rejection Combining (Uplink) BSS R10• Antenna Hopping (Downlink) BSS R10• Frequency Hopping (Uplink & Downlink) before BSS R8 • Adaptive Multi Rate FR (Uplink & Downlink) BSS R9.1



Signal strength design targetsHardwareFeaturesInterference Rejection Combining

(IRC)• Co-channel interference suppression algorithm on the uplink.

• Possible together with dTRU, EDGE dTRU and EDGE sTRU

• IRC improvement– 5-11 dB for 1 frame synchronized interferer – 3-5 dB for 1 non-synchronized interferer

(The interference will be synchronized if Transceiver Group or Network Synchronization is used. Network Synchronization is released in BSS R10.)

• Requirement : RX diversity must be configured



Signal strength design targetsHardwareFeaturesAntenna Hopping

• Transmit radio bursts on alternating antennas.

• Possible together with CDU-G or CDU-C/C+ with EDGE sTRU.

• C/I gain for TCH– up to 2 dB when hopping on few frequencies– up to 3 dB without frequency hopping

• Together with TCC, two transmitter paths both with TCC is needed.

• Requirement : Needs two transmitter antennas or one cross polarized antenna.



Signal strength design targetsHardwareFeaturesFrequency Hopping

• Frequency hopping improve the C/I robustness by using frequency diversity to avoid continuous interference and Rayleigh fading.

• Interleaving used for speech frame will be utilized more efficient with frequency hopping.



Signal strength design targetsHardwareFeaturesAdaptive Multi Rate FR (AMR FR)

• With AMR FR the speech codec will be adapted to the C/I conditions for each call.

• Since control channel coding will limit the physically coverage, AMR FR will not increase coverage.

• AMR FR will improve the C/I robustness for speech users with up to 6dB.



Recommended Coverage Configurations Function Config. 1 Config. 2 Config. 3

CDU choice CDU-G CDU-G CDU-C+TCC x

SPWB x xAntenna Hopping x x x

Rx Diversity x x xTMA x x x

IRC (1) x (2) x xFrequency Hopping (1) x x x

AMR (1) x(2) x x

(1) Will not increase coverage for common control channels (2) s-TRU needed



Summary

AMRFrequency Hopping

Antenna choice

IRCRx Diversity

TMA

Antenna HoppingSPWBTCC

CDU choiceUL / DL

DLDLDLDL

ULULUL

UL, DLUL, DLUL, DL

Function HW / SWHW

HW, SWHW, SWHW, SW

HW HW, SW

SW

HW SWSW

It should be noted that the gain from the features are not additive.



References

- RF Guidelines GSM 800 20/10056-HSC 103 12/3 Uen- RF Guidelines GSM 900 16/10056-HSC 103 12/3 Uen- RF Guidelines GSM 1800 17/10056-HSC 103 12/3 Uen- RF Guidelines GSM 1900 18/10056-HSC 103 12/3 Uen- User Description, Boosting Downlink Output Power 107/1553-HSC103 12/3 Uen- User Description, Interference Rejection Combining 103/1553-HSC 103 12/4 Uen- User Description, Antenna Hopping 102/1553-HSC 103 12/4 Uen- User Description, Frequency Hopping 63/1553-HSC 103 12/3 Uen- User Description, Adaptive Multi Rate 98/1553-HSC 103 12/3 Uen

signal strength coverage aspects-r10

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