The evolution of channel bandwidths in 5G NR has been relatively conservative compared to earlier generations, but recent developments in 3GPP Release 19 show that this is beginning to change. The introduction of 7 MHz channel bandwidth in FR1 marks an important step towards addressing practical spectrum realities that many operators have faced since the early days of NR.
In the original 5G NR specifications, channel bandwidths were defined in regular steps of 5 MHz, such as 5, 10, 15, 20 MHz and so on. This design choice simplified implementation and aligned well with clean spectrum allocations. However, real world spectrum holdings are rarely so neat. Many operators hold fragmented or irregular chunks of spectrum, particularly in low bands where legacy allocations and refarming have resulted in non standard bandwidths.
This was not a new problem. LTE had already addressed this challenge by supporting a wider range of channel bandwidths including 1.4 MHz and 3 MHz, in addition to the more common 5, 10, 15 and 20 MHz. Combined with carrier aggregation, LTE allowed operators to make efficient use of spectrum even when it was not aligned to neat multiples. When NR was introduced, this flexibility was initially reduced, creating a gap between specification and deployment reality.
Recognising this limitation, 3GPP introduced a 3 MHz channel bandwidth in Release 17 and continued refining spectrum flexibility in Release 18. The addition of 3 MHz was an important step, particularly for narrowband and coverage focused deployments, and it allowed combinations such as 8 MHz or 13 MHz to be better utilised through aggregation.
However, this still did not fully solve the problem. Operators continued to highlight the need to support other irregular bandwidths such as 6, 7, 11 and 12 MHz. These are not edge cases but reflect actual spectrum holdings in several bands. Release 19 addresses this directly by introducing native 7 MHz channel bandwidth.
The standardisation of 7 MHz focuses on FR1 operation, initially targeting bands such as n5 and n26. Rather than relying on workarounds such as overlapping channels or using the next larger bandwidth, this approach defines 7 MHz as a native channel bandwidth within NR. This avoids some of the practical issues associated with earlier approaches, including blocking from adjacent operators and compatibility challenges with legacy devices.
The work also includes a comprehensive set of requirements covering both core and performance aspects. These span RF requirements for user equipment and base stations, spectrum utilisation considerations, and the necessary signalling updates across the protocol stack. The effort is led by RAN4, with coordination from RAN2 and RAN3 to ensure seamless integration into the NR framework.
An interesting aspect of this development is the constraint to 15 kHz subcarrier spacing. This reflects the focus on low band and coverage scenarios where such numerology is most relevant. It also helps to limit complexity while still delivering the intended benefit of improved spectrum utilisation.
From a deployment perspective, the introduction of 7 MHz fills an important gap. While 3 MHz enabled some additional flexibility, it was not sufficient to address all irregular spectrum cases. With 7 MHz, operators gain a more practical option that aligns better with real spectrum allocations, especially in bands where 6 or 7 MHz chunks are common.
It is also worth noting that this is likely not the end of the story. Earlier study work identified several other irregular bandwidths that could be useful. The inclusion of 7 MHz in Release 19 can be seen as a pragmatic step, with the possibility of extending similar support to other bandwidths in future releases once the framework is established.
In many ways, this development reflects a broader trend in 5G and beyond. Early specifications tend to favour simplicity and clean design, but as deployments mature, practical considerations drive the need for greater flexibility. Spectrum is one of the most valuable assets for operators, and the ability to use it efficiently, regardless of how it is fragmented, is critical.
The addition of 3 MHz in earlier releases and the introduction of 7 MHz in Release 19 shows that NR is evolving in that direction. It is a reminder that standardisation is not just about defining ideal systems, but also about adapting to the realities of how networks are deployed and operated.
Ericsson’s blog provides a useful background on the introduction of 3 MHz bandwidth in Release 18, available here. Further technical details on the 7 MHz enhancement can be found in RP-251453, which describes the NR FR1 7 MHz channel bandwidth Work Item.
Related Posts:
- The 3G4G Blog: 3GPP Release 19 Description and Summary of Work Items
- Free 6G Training: ATIS Webinar on 3GPP Release 20 and the Growing Shape of 6G
- Free 6G Training: ATIS Webinar on 'Introduction to 3GPP Release 19 and 6G Planning'
- The 3G4G Blog: 3GPP Release 18 Description and Summary of Work Items
- The 3G4G Blog: 3GPP Release 17 Description and Summary of Work Items
- The 3G4G Blog - Tutorial: A Quick Introduction to 3GPP
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