r more sectors with an average efficiency of between 2 and 3 bits per Hz. This is a gigabit rather than megabit discussion. The offered traffic limit in this case would probably be the battery and heat-rise limitations of the user devices accessing the network and/or the number of users you would need to pack together to use the bandwidth in a small to medium-size cell. You may as well deliver television to each site as well adding a few more gigabits to the backhaul mix at least in one direction. Microwave vendors might argue that whatever the loading microwave can provide enough capacity just by adding more bandwidth. However, given that the dish antennas are band specific this implies a lot of antenna hardware on a site/mast that might be space- and weight-loading constrained. Line-of-sight problems would also shift the balance towards copper or fibre. 13.4 The HRAN and LRAN The relative technology economics of wireless versus copper and fibre are therefore complex with many interdependencies. Ericsson makes things simpler³ by dividing mobile broadband backhaul into two parts, the lower radio access network (LRAN) and the high radio access network (HRAN). The HRAN aggregates traffic from several LRAN networks using fibre or microwave. The LRAN provides the last mile of connectivity to anything between 10 and 100 radio base station sites normally, though not always, using microwave but with fibre and copper as alternative options. They make the completely obvious point that microwave will generally have the lowest cost of ownership unless an alternative is already there or physically close. However, as you would expect from a vendor with very positive ambitions for LTE the argument is made that at some point in time some base stations may need gigabit backhaul links. The regulated licensed spectrum between 6 GHz and 38 GHz supports channel bandwidths up to 50 MHz, which with high-level modulation can just about deliver 500 Mbps under ideal conditions. Adding polarisation multiplexing and multiple input/output t