Which UEs Support E-UTRA and New Radio Dual Connectivity in UEs which support

Shares

​The base station architecture deployment options in case of Non-standalone deployment are depicted in Figures 1, 2 and 3 below. Option 3, Option 3a and Option 3x. 

​Figure 1: Non-Standalone Base Station Architectures using the 4G Core Network Option 3

​Figure 2: Non-Standalone Base Station Architectures using the 4G Core Network Option 3a

​Figure 3: Non-Standalone Base Station Architectures using the 4G Core Network Option 3x

​What is EN-DC?

​The options listed in Figure 1, 2 and 3 are known as E-UTRA  - New Radio Dual Connectivity (EN-DC).   E-UTRA refers to the 4G air-interface  and New Radio refers to the 5G air-interface.  This naming convention orders the air interface technologies according to Master Node followed by Secondary Node. In case of EN-DC --- E-UTRA is the Master Node so is named first.

​UEs supporting EN-DC

​UEs which support EN-DC are required to be capable of receiving downlink data at the same time across 4G and 5G air-interfaces.   In 3GPP release 15, EN-DC bands for up to 5 different operating bands are included.

 Generally UEs which support EN-DC are required to be capable of transmissiting uplink data at the same time across 4G and 5G air interfaces.

​A UE with 2 transmitters can generate inter-modulation products which fall within the UE's receive bandwidth. In other words, UE can desensitise itself by generating interference (inter-modulation products) within its own downlink receiver.

​Figure 4: Illustration of 2nd order Inter-Modulation Products

  • ​In Figure 4, it shows an example of using operating band 1 for 4G and operating band 77 for 5G.  Second order inter-modulation products are generated according to (f2-f1). It leads to inter-modulation products within the range 1320 MHz to 2280 MHz across the downlink of operating band 1. The inter-modulation products will not always coincide with the downlink of operating band 1 but will depend upon the specific allocation within each band.  
  • 3GPP TS 38.101-3 lists which band combinations allow single uplink transmission.  UE manufacturers can use decided whether or not to support multiple simultaneous uplink transmission for these band combinations


References

  1. 3GPP TS 36.331
  2. 3GPP TS 38.101-3
  3. 5G NR in Bullets by Chris Johnson
>