I doubt if you can really simulate US cellular network from India. You can at max change your geolocation by using VPN or some other Proxy software but you won't be able to replicate the cellular connectivity of US from India. At Least I was not able to do so when it was required from me.
Quality Assurance Lead, India
"A Cat looked at the mirror and what she saw was a Lion. Secret of success depends on how you see yourself."
What is it about the network you want to simulate?
For the most part, unless there's some sort of specific integration deal with a particular carrier. Most people will test network conditions using a proxy and using it to introduce either latency or packet loss. Using those 2 concepts you can simulate a wide range of network conditions such as jitter, longer delays from distance, unstable connections, etc...
2 that I've used are Charles Proxy and Wireshark. Both are good tools I think should be in the tool belts of anyone testing network / transport layer software.