NR module cttc-lte-ca-demo.cc

[krishna reddy]

Dear 5G-LENA group members,  

Can someone analyze why the CA throughput is not showing correctly in the NR module cttc-lte-ca-demo.cc? The aggregated throughput for both FDD and TDD modes is identical, whether using three (3) CCs or just one (1) CC. Please let me know what changes are necessary to properly capture CA performance in cttc-lte-ca-demo.cc. i am attaching corresponding results here.

In another scenario, during simulation in FDD mode, the following results were observed on downlink side:

For a single component carrier (1-CC) with a 50 MHz channel, the throughput achieved was 163.73 Mbps.

For a single component carrier (1-CC) with a 10 MHz channel, the throughput was 31.26 Mbps.

For five component carriers (5-CCs) each of 10 MHz (totaling 50 MHz), the throughput remained 31.26 Mbps

Krishna 

[Gabriel Ferreira]

I'm not sure if that used to work in 5G-LENA, but as far as I understood working with the code, these CCs are actually just BWPs, which according to NR standards the UE can have up to 5, but a single one can be active at a time.
There was this big confusion, because NR relied on LTE upper layers, which does not consider BWPs.
We could allow more than one active simultaneously, to get this scaling (not standard compliant, but should emulate it well), but I'm not there yet.

[Gabriel Ferreira]

Krishna, just an update, after talking with Biljana I understood that you can have this scaling effect, as long as you setup different bearers and allocate them to different BWPs. This way multiple applications can benefit from the extra bandwidth.

This is what is done in cttc-nr-cc-bwp-demo, with 4 separate BWPs for different 5QIs

    nrHelper->SetGnbBwpManagerAlgorithmAttribute("NGBR_LOW_LAT_EMBB",
                                                 UintegerValue(bwpIdForLowLat));
    nrHelper->SetGnbBwpManagerAlgorithmAttribute("GBR_CONV_VOICE", UintegerValue(bwpIdForVoice));
    nrHelper->SetGnbBwpManagerAlgorithmAttribute("NGBR_VIDEO_TCP_PREMIUM",
                                                 UintegerValue(bwpIdForVideo));
    nrHelper->SetGnbBwpManagerAlgorithmAttribute("NGBR_VOICE_VIDEO_GAMING",
                                                 UintegerValue(bwpIdForVideoGaming));