Delivered Aug 29, 2019 Presented by Eshwar M. View this webinar to learn the features of 5G MR-DC. You'll learn what it is, the benefits and features, architecture, and various deployment options supporting MR-DC.
1. I have a fundamental question that relates to Dual Connectivity i.e. N-DC refers to the dual connection of 4G wireless access network and 5G NR. 2. Let’s say that we are using Band-X in 4G and another similar band in 5G and are attempting to communicate with both RATs to take advantage of EN-DC. 3. The question is what will happen if there is overlap in terms of the “spectrum occupied”. 4. Let’s say that the 4G component has been assigned spectrum in Band 3 from 1830 MHz through to 1850 MHz (i.e. a chunk of 20 MHz Bandwidth). 5. Let’s say that the 5G component has been assigned spectrum in Band n3 from 1820.45 MHz through to 1830.45 MHz (i.e. a chunk of 10 MHz Bandwidth). 6. In such a scenario, there is an overlap of 450 KHz between these two components i.e. the assigned 5G-NR band component eats into the 4g spectrum component by 450 KHz. 7. Will such a deployment work in light of the designated configuration based on existing product implementations? There are bound to be issues in decoding such transmissions at the UE because of the overlap in the spectrum. The reason, I am asking this question was because an argument (however erroneous) can be made that the 5G transmissions would potentially be orthogonal to the 4G transmissions (even if they have an SCS of 15 kHz or 30 kHz) and hence the decoding at the mobile will work because orthogonality will prevent any decoding issues. I do not agree with this argument i.e. that the orthogonality provided by the OFDM structure of the waveforms would protect them against each other (i.e. from the UE perspective in the sense that the UE can successfully decode the two transmissions). I would be very grateful if you could enlighten me with your perspective with references (if applicable). 8. If the answer is in the negative, from an R&D implementation, perspective - what changes would one need to implement to make such a configuration (i.e. characterized by overlapping assigned spectrums) workable in realistic network implementations? 9. It would also be immensely helpful if you could further substantiate your arguments with references from the relevant 3GPP specifications (or other relevant specifications) or draw my attention to any specific specifications or publications which can further clarify my doubt?
Does UE communicates with both MN(master node) and SN(Secondary Node) at same time, or only after MN selects/configure SN then only UE communicates with SN?
UE Communicates periodically with both MN and SN. Core provides info about the base stations reachable at UE. Based on some algo base station decides SN and provides DC. Correct me.
Hi there! Thank you for your question! The use of NR-PDCP or E-UTRAN PDCP depends on type of bearers supported in EN-DC configurations. For example, the SCG bearer and split bearer at the SCG etc. use NR-PDCP whereas the MCG bearer is allowed to use either E-UTRAN PDCP or NR-PDCP. For further details, you can refer to 3GPP TS 37.340 : section 4.2.1 and 4.2.2( E-UTRA and NR; Multi-connectivity) which has figures related to both the 5G-RAN and UE perspective. Hope this helps!
