Pros
Huawei's Russian R&D Centre (Moscow) is a great professional community of specialists in signal processing and related topics indeed. It absorbs talented people (mainly, men) from all over Russia and puts them together into a "thinking and developing tank".
Cons
I had a probationary period for three months. I was assigned several mathematical problems to solve. Specifically, the company wanted to know if a particular math algorithm with certain simplifications would be as much accurate as some baseline sophisticated algorithm currently used by Huawei. So, formally I did solve the problem and showed that 1) although the simplified method does work, 2) it cannot provide the same performance as the sophisticated method does. Surprisingly, I was suggested we should terminate the contract within the next three months. Besides, I was not given any explanation from the head of the department --- simply was faced with the fact.