Why to Decouple the Uplink and Downlink in Cellular Networks and How To\n Do It

Ever since the inception of mobile telephony, the downlink and uplink of\ncellular networks have been coupled, i.e. mobile terminals have been\nconstrained to associate with the same base station (BS) in both the downlink\nand uplink directions. New trends in network densification and mobile data\nusage increase the drawbacks of this constraint, and suggest that it should be\nrevisited. In this paper we identify and explain five key arguments in favor of\nDownlink/Uplink Decoupling (DUDe) based on a blend of theoretical,\nexperimental, and logical arguments. We then overview the changes needed in\ncurrent (LTE-A) mobile systems to enable this decoupling, and then look ahead\nto fifth generation (5G) cellular standards. We believe the introduced paradigm\nwill lead to significant gains in network throughput, outage and power\nconsumption at a much lower cost compared to other solutions providing\ncomparable or lower gains.\n