Mobile Sensing Measurement Report for supporting 1x Active Hand-in

Peerapol Tinnakornsrisuphap (peerapol@qualcomm.com)Chirag Patel (cpatel@qualcomm.com)

Doug Knisely (dknisely@airvana.com)

May 11th, 2009

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Overview

• To support 1x active hand-in using mobile sensing approach (refer to contribution A20-20081027-008r0), the FCS needs to request candidate target FAPs to perform measurement and report measurement information to the FCS

• This presentation discusses the definition, range and granularity of this information

How to determine hand-in candidate?

• The best FAP hand-in target should be the FAP that can hear the MS on the RL –and- has the best FL pilot to the MS

RL pilot

FAP1FAP2

In this example, while the MS is physically closer to FAP1 and FAP1 can detect the MS strongest RL signal, it is not the suitable handoff target as its FL coverage does not reach the MS.The FL pilot power is adjusted based on various factors and is likely different for each FAP

FL coverage

RL pilot

Using RL pilot measurement and FL Pilot Tx power

• EcpRL measurements identify a FAP with the best RL• Since FAPs may have different FL Tx powers, using

EcpFL-Tx together with EcpRL helps in identifying FAP with the best FL to the MS– Refer to the formulation in the appendix

• Example: when FAPs sense a MS’s RL and feed back (EcpFL_Tx + EcpRL) to the network, the HO target FAP can be identified as the one with the largest (EcpFL_Tx + EcpRL) metric

• The remaining of this contribution describes the definition and how to code these fields

Femto Transmit Pilot Power

• Definition: The FAP shall set this field to indicate the Pilot Channel Power of its service channel

• Value (8 bits): – The FAP shall set this field to the two’s

complement representation of the Pilot Channel Power of its service channel (in dBm)• Translate into range of [-128, 127] dBm• Typical range: -30 dBm to +20 dBm, 1 dBm granularity

Measured Received Pilot Power

• Definition: The FAP shall set this field to the received power, measured at the base station RF input ports, of the pilot channel of the MS

• Value (8 bits): – The FAP shall set the value of this field to -2 x the

received power (in dBm)• Translate into range of [-127.5, 0] dBm at 0.5 dBm

granularity– Typical Rx pilot power (Ecp): -10 dBm to -120 dBm

• Assuming Tx reverse-link range: -90 dBm to 23 dBm• Pathloss: 30 dB to 150 dB

Measurement Report Time

• The FCS indicates when it expects the FAP to send measurement response back

• If FAP does not have enough time to measure satisfactorily, it sends back results to FCS with error cause value indicating not enough time to measure

Open issues

• Measurement Start Time and Duration– Whether it is necessary for each FAP to start the

measurement at the same time and whether the measurement should last the same duration

DERIVATION OF HANDOFF METRICAppendix

Comparing best FL between two FAPs

• Consider two FAPs using the same pilot PN, their FL Ecp/Io (in dB) at the MS are:

where EcpFL1_Tx and EcpFL2_Tx are FL pilot Tx powers (dBm) and PLFL1 and PLFL2 are FL path loss (dB) from the two FAPs and Io (dBm) is the total received signal power plus noise.

• Conceptually, HO target is the FAP with the best FL Ecp/Io or equivalently the best FL Ecp and can be determined by using the following HO metric (in dB):

If the result is greater than zero, then FAP1 is the target FAP

,/

/

2_22

1_11

IoPLEcpIoEcp

IoPLEcpIoEcp

FLTxFLdBFL

FLTxFLdBFL

12_2_121 FLFLTxFLTxFLFLFL PLFPLEcpEcpEcpEcp

Estimating the Pathloss• Assuming FL and RL path losses are identical (PLFL1 = PLRL1, PLFL2

= PLRL2), RL pilot measurements at FAP can be used to get the relative pathloss as

• where EcpRL_Tx is MS’s pilot Tx power (dBm). The HO decision metric becomes

i.e., FAP1 is the target FAP if the above calculation is greater than zero

,2112

2_2

1_1

RLRLRLRL

RLTxRLRL

RLTxRLRL

EcpEcpPLPL

PLEcpEcp

PLEcpEcp

2_21_121 RLTxFLRLTxFLFLFL EcpEcpEcpEcpEcpEcp