How to improve performance of GeoIP query in BigQuery?

I have loaded my application logs in BigQuery and I need to calculate country based on IP address from those logs. I have written a join query between my table and a GeoIP mapping table that I downloaded from MaxMind. An ideal query would be OUTER JOIN with range filter, however BQ supports only = in join conditions. So the query does an INNER JOIN and handles missing values in each side of the JO