A key consideration for small cell deployment is the backhaul. There are some challenges associated with backhaul for example, wireline backhaul such as fiber and Ethernet are not always available at the desired locations. In addition, wireless backhauls using microwave and millimeter-wave require line-of-sight (LOS) to the aggregation point which may be a problem in urban areas with high-rise buildings.
Qualcomm Research has come up with a solution to help mitigate these challenges by using relays that use wireless backhaul to enable small cell deployment in backhaul constrained areas. Relays are optimal because they can choose the best node to use among nearby Macros or wired Picos for backhaul connection. A key benefit of relays can be seen when using sub 6GHz spectrum. In this case, non line-of-sight (NLOS) backhaul connection is supported which greatly improves small cell site selection flexibility. In turn, the backhaul is able to share the same LTE carrier by which UEs access Macro or wired Picos directly, therefore significantly reducing backhaul deployment cost and operating expenses.
Qualcomm Research has successfully demonstrated prototype relays with LTE-based NLOS wireless backhaul in our over the air networks in San Diego.