As of now (Sep 2016), 3GPP Conformance Test Case (36.521-1,36.521-3,36.523) for LTE-M1 has not been defined yet. Even thought several chipset makers has announced/claimed that their product has been supporting LTE-M1 for almost over an year, I have been seeing real/practical verification activity only recently. So I guess (I think), most of the chipset maker/product is at some point of protocol stack integration. So I decided to write down some general approach to early integration test. This is just beginning.. and I will keep updating this.

That was written in September 2016, and the situation has changed since. 36.521-1 V19.2.0 now carries Cat M1 test cases. The RF transmitter and receiver tests carry an EA suffix, for example 6.2.2EA UE Maximum Output Power for UE category M1 and 7.3EA Reference sensitivity level for UE category M1. The demodulation tests sit in clause 8.11, Demodulation (UE supporting coverage enhancement), and CSI reporting sits in clause 9.8. The integration steps below come earlier in the life of a modem, and each of them maps to one of those clauses.

Followings are the topics to be covered in this page.

• Downlink Physical Channel/Scheduling Test
• PBCH Decoding
• BCCH-DL-SCH : PDSCH
• CCCH/DCCH/DTCH : PDSCH
• MPDCCH
• Reference

Downlink Physical Channel/Scheduling Test

Downlink testing starts with the channels a UE has to decode before it can do anything else. The subsections below take them one at a time, from PBCH to MPDCCH. Each table lists the parameters to fix in the eNB simulator, and the note after it names the 36.521-1 clause that tests the same channel for conformance.

PBCH Decoding

Basically this is to test MIB decoding capability. Since almost all of the parameters to implementing PBCH is predefined by 3GPP standard, there is almost nothing to be configured in eNB simulator and UE modem. But to verify if UE properly decode PBCH is important because LTE-M1 MIB is transmitted in different subframe from legacy LTE and Resource Element Mapping is pretty much different from legacy LTE due to repetitive transmission of PBCH in LTE M1.

For conformance, 36.521-1 V19.2.0 tests this channel in clause 8.11.3, Demodulation of PBCH (enhanced coverage). The legacy PBCH demodulation test stays in clause 8.6.

BCCH-DL-SCH : PDSCH

In this channel, you need to verify on two different cases. One is the case of SIB1-BR and the other case is for other SIBs (non SIB1). In terms of Baseband I/Q generation and Resource Element mapping, there is no fundamental difference between these two case, but there are some differences in terms of scheduling and resource allocation. So, if you want to do test on this channel purely on physical layer perspective, you may test this as a single category, but if you want to test including MAC scheduling aspect as well, I would divide this into two categories.

Case 1 : PDSCH for SIB1-BR

Case 2 : PDSCH for non-SIB1-BR

The two tables differ in size for a reason. SIB1-BR is scheduled by a single MIB field, because the UE has not read any SIB yet. Its narrowband and start symbol come from fixed rules in 36.211 and 36.213, and the SIB page works through them. The other SI messages are configured in SIB1-BR, so the test needs every field listed in Case 2.

CCCH/DCCH/DTCH : PDSCH

The parameter setting for PDSCH for User Data is relatively straightforward (Physical Layer's point of view, most of C plane data(e.g, CCCH/DCCH) can be regarded as user data)

For conformance, 36.521-1 V19.2.0 tests this PDSCH in clause 8.11.1. One example is 8.11.1.1.3.1, FDD and half-duplex FDD PDSCH Transmit Diversity 2x1 for UE category M1.

MPDCCH

In most test equipment (especially protocol test equipment), MPDCCH related parameters are not directly configured by user. They are automatically calculated/configured by other parameter (mostly by PDSCH scheduling parameter). But if your DUT's blind decoding algorithm is not complete and you want to set any specific set of parameters, you would need to specify following tables and configure PDSCH scheduling parameters so that the test equipment would generate the specific MPDCCH parameters as you want.

For conformance, 36.521-1 V19.2.0 tests MPDCCH demodulation separately for each CE mode. Clause 8.11.2.1.1 covers FDD and HD-FDD in CE Mode A, and clause 8.11.2.1.2 covers FDD and half-duplex FDD in CE Mode B. TDD has its own pair in clause 8.11.2.2.

• PBCH comes first : MIB decoding checks the repeated PBCH and gives schedulingInfoSIB1-BR-r13 for the next step.
• SIB1-BR needs one parameter, the other SI messages need five : the MIB schedules SIB1-BR, and SIB1-BR schedules the rest.
• User data PDSCH needs a full scheduling setup : narrowband, repetition level, MCS and start symbol all come from the eNB simulator.
• MPDCCH parameters usually follow PDSCH scheduling : set them directly only when the DUT's blind decoding needs a fixed case.
• Every step has a conformance clause : 36.521-1 clause 8.11 covers PBCH, PDSCH and MPDCCH for UEs supporting coverage enhancement.

Reference

[1] 3GPP TS 36.521-1 V19.2.0 - clauses 6 and 7 for the UE category M1 RF tests, clause 8.11 for demodulation and clause 9.8 for CSI reporting of UEs supporting coverage enhancement