New Mid-Band for 6G: Several Considerations from the Channel Propagation Characteristics Perspective

To realize the sixth-generation (6G) vision may require additional spectrum to support the framework and objectives. The sub-6 GHz of fifth-generation (5G) can be used for spectrum refarming, but we also need to find more spectrum with larger bandwidth. This article focuses on the new mid-band (6-24 GHz) that 6G is concerned with, and gives several considerations from the channel perspective. First, we review the global efforts in recent years to study the candidate frequency bands for 6G, as well as spectrum-related works and views of the different organizations. Second, from large/small-scale fading and new characteristics, the recent research findings and considerations are investigated for the channel of the different bands. The channel characteristics of the new mid-band and the influence on the system performance are discussed in depth. Some views and suggestions on the reasonable utilization of the new mid-band for 6G communication systems are put forward. Finally, open issues and future research directions for the 6G spectrum are pointed out. This article sheds light on the more reasonable use of the new mid-band for 6G.