Nokia and KT have been working closely together to prepare for a deployment of the world’s first mobile 5G network in South Korea in 2017. Here’s the inside scoop:
Initially Nokia, KT, and several other key players in the wireless industry, came together to specify a 5G commercial trial system to operate in the 28GHz band. The system is designed to support multi-gigabit user data rates and massively reduced latency, leading to transformed user experience of wireless services.
But deploying 5G in the real world is much more than specifying a system. Accurate, robust network planning will be crucial for the successful roll-out of 5G-supported services. While network planning is seldom trivial, for high-frequency 5G systems, it is an exceptionally challenging undertaking, as 28GHz technology and deployments are new to our industry. To take just one example, the 28GHz band is sensitive to all kinds of blockages, including those caused by human bodies which may block the line-of-sight between device and base station. In addition, the first deployments will be in areas with significant levels of construction over the next two years. Many of the buildings are still just blue prints, making it difficult to perform accurate field measurements!
Nokia Bell Labs, with support from the Nokia Korea Advanced Technology Center (ATC), took on the challenge and provided initial network plans for the deployment area in Korea using 3D maps, accurate ray-tracing based simulations, and extensive Nokia Bell Labs know-how from prior 5G radio channel modeling work.
Addressing key network planning challenges
With a whopping 800MHz system bandwidth and more than 20Gpbs cell throughput, lack of capacity is not the first concern in the network planning process. However, operation at the 28GHz band sets new challenges in terms of coverage, given its more challenging radio propagation characteristics compared to that of current 4G frequencies.
One of the benefits of using higher frequency bands like this, is that they enable deployment of antennas with higher gain (and narrower radio beams). In the areas which had line-of-sight (LOS) to the nearest base station sites, we found that the higher antenna gains indeed helped to compensate for the larger radio propagation loss, and coverage from existing sites was still fairly good. However, in non-line-of-sight (NLOS) locations, coverage was very limited. NLOS coverage was observed mainly in areas that were close to cell sites and benefited from reflections from nearby buildings. Overall, the number of sites had to be roughly doubled in order to create sufficient outdoor coverage, which was a surprisingly low increase for such a high frequency.
Our study also showed that the traditional three-sector deployment is not necessarily ideal when building the coverage at 28GHz on existing sites. Instead, we found that four sectors (or more) is a better option to ensure good coverage, particularly in the sector border areas.
These Nokia findings, among many other network planning insights obtained from the study, are seen by KT as an important step towards the common goal – a successful deployment of world’s first mobile 5G network in 2017.
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