How will 5G DAS and 4G/LTE DAS implementations differ?
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in the 5G Magazine
What are the frequency bands associated with 5G?
5G technology is carried over low, mid, and high-frequency bands with their own characteristics that alter how distributed antenna systems must be architected within buildings. High bands, such as mmWave, provide the fastest speeds and lowest latency but cover shorter distances and are easily disrupted by man-made and natural obstacles. Conversely, low bands like 600MHz offer slower 5G speeds but can travel longer distances and are more resilient to interference by materials. Mid band frequencies 2.5GHz and C-band are middling in both coverage and speeds.
For the purposes of this discussion, the two primary 5G frequency bands we expect to see moving forward are mmWave and C-band. Each brings different strengths to a 5G deployment, helping to create tailored signals for specific use cases. mmWave has the highest bandwidth of available technology, while C-band is a newer trend in the wireless industry. During a recent auction, all major carriers bid heavily on C-band and spent over $80 billion.
What’s different about mmWave?
mmWave provides higher bandwidth than C-band, allowing for better download and browsing speeds, as well as lower latency. The caveat is that it does not travel as far as other bands as it requires a line of sight to the antenna. With this smaller coverage area, mmWave DAS needs more antennas in a space than a 4G/LTE system would require.
This is the same trend we saw when we jumped from 3G to 4G/LTE frequencies. Repeater placement can also help overcome any problem areas, like stairwells, where coverage propagation is a challenge.
What’s C-band’s role?
C-band has a higher frequency than bands used for 4G/LTE technology, but has higher antenna sensitivity, meaning it doesn’t propagate as well. When compared to 4G/LTE, C-band is better for wider deployment, but increased antenna sensitivity requires a denser antenna deployment within the DAS. It doesn’t require as much as mmWave, but it’s an increase from the previous generation. C-band can go through walls and its DAS is implemented in the same way as 4G/LTE bands.