The incident happened on Rookery Avenue near to Caspian Close between 5.40pm and 5.50pm.
The victim had been walking from the train station when he was approached by three unknown boys who then assaulted him and took his mobile phone. The victim was not injured.
Anyone with information can phone 101 with reference 44210253037. Alternatively, you can call Crimestoppers 100% anonymously on 0800 555 111