KUALA LUMPUR: U Mobile Sdn Bhd and Malaysia Rapid Transit Corporation Sdn Bhd (MRT Corp) have signed a memorandum of understanding (MoU) to explore 4G and 5G provision at the Immigration, Customs and Quarantine Complex (ICQC) in Bukit Chagar, Johor Baru, before the opening of the Johor Baru-Singapore Rapid Transit System (RTS) Link.