I.2 Sensitivity and Interference Performance
3GPP45.005GSM/EDGE Radio transmission and receptionTS
This clause specifies the required E-OTD measurement accuracy for an E-OTD capable MS with and without interference. The requirements are given in terms of E-OTD measurement error (in microseconds), as function of the carrier and interference input power levels, at the antenna connector of the receiver. Equipment with an integral antenna may be taken into account in a similar manner as described in Chapter 5 of 3GPP TS 45.005.
The power level, under multipath fading condition, is the mean power of the sum of the individual paths.
I.2.1 Sensitivity Performance
With the following configuration and propagation conditions, the E-OTD capable MS shall meet the requirements of 90% RMS E-OTD error defined in Table I.2-1.
– The E-OTD capable MS is in dedicated mode receiving a carrier signal at a power level of at least 20 dB above the reference sensitivity level defined in subclause 6.2.
– The E-OTD measurements are done on a neighbour BCCH carrier at power levels relative to the reference sensitivity level defined in subclause 6.2. The measurement power levels are given in Table I.2-1. The E-OTD measurements are referenced to a reference BCCH carrier at a power level at least 20 dB above the reference sensitivity level defined in subclause 6.2. The reference BCCH carrier and the neighbour BCCH carrier shall be in the same frequency band. The BA list contains the reference BCCH carrier and the neighbour BCCH carrier.
– The network requests an E-OTD measurement by commanding the E-OTD capable MS to report the E-OTD measurement with a response time equal to 2 seconds. The E-OTD capable MS does not need to perform E-OTD measurements prior to receiving the command.
– The measurement performance shall also be achieved with the reference BCCH and the neighbour BCCH carriers having 8-PSK modulated bursts. 8-PSK modulation and the 8-PSK normal bursts are defined in 3GPP TS 45.004 clause 3 and 3GPP TS 45.002 subclause 5.2.3, respectively.
– The measurement accuracy of the E-OTD capable MS is defined as the root-mean-square (RMS) value of 90% of the measurements that result in the least E-OTD error. As an example, if {x1..xN}is a set of the absolute square E-OTD measurement errors for N trials, sorted in ascending order, the RMS of 90% is defined as
RMS90 = sqrt( sum(x1..xM)/M )
where M is the largest integer such that M < 0.9 N. For the test, N > 250 trials is recommended.
The channels shall be static, i.e. at a constant signal level throughout the measurements.
Table I.2-1: Sensitivity performance
(RMS90 of E-OTD error in microseconds)
|
Minimum neighbour carrier signal strength relative to reference sensitivity level |
Staticchannel |
|
–8 dB |
0.3 s |
|
12 dB |
0.1 s |
I.2.2 Interference Performance
In this clause, requirements are given in terms of the E-OTD measurement accuracy (in microseconds) for specified carrier-to-interference ratios of the neighbour BCCH carrier. The carrier the MS uses for communication and the reference BCCH carrier shall be as defined in section I.2.1. The input neighbour BCCH carrier signal shall be as defined in I.2.1 and shall be set to a level at least 20 dB above the reference sensitivity signal level defined in subclause 6.2. The C/I requirements shall be met for an interference signal which is co-channel, adjacent channel (200 kHz offset), and alternate channel (400 kHz offset) to the desired neighbour BCCH carrier as shown in Table I.2-2 below.
– The interference signal consists of a random, continuous GMSK modulated signal.
Table I.2-2: Interference performance
(RMS90 of E-OTD error in microseconds)
|
Interference type |
Static Channel |
Minimum carrier to Interference Level (dB) |
|
Co-channel |
0.3 s |
0 dB |
|
0.1 s |
10 dB |
|
|
Adjacent channel |
0.5 s |
-18 dB |
|
0.2 s |
-8 dB |
|
|
Adjacent channel |
0.1 s |
-41 dB |
I.2.3 Multipath Performance
This clause defines E-OTD measurement accuracy under multipath conditions. The test setup is as under I.2.1 (sensitivity performance) with the following changes:
– Each burst of the neighbour BCCH carrier propagates through the TU multipath channel specified in Annex C of 3GPP TS 45.005. The reference carrier remains static.
The performance requirements are specified in Table I.2-3.
Table I.2-3: Multipath performance
(RMS90 of E-OTD error in microseconds)
|
Minimum neighbour carrier signal strength relative to reference sensitivity |
TU3 |
|
-8 dB |
1.5 s |
Annex J (informative):
Guidance on the Usage of Dynamic ARFCN Mapping