Backhaul Research Note:TDD in Small Cell Backhaul

Until the first unlicensed TDD (Time Division Duplexing) standards such as Bluetooth and IEEE 802.11a/b where approved in the late 1990s, FDD (Frequency Division Duplexing) had been the de-facto duplexing technique in wireless communications. When 3G spectrum was allocated in Europe, licensed TDD spectrum was considered for the first time as a complement to the traditional FDD. However, the real applications of TDD 3G technology were little more than a big question mark at a time when FDD 3G’s killer application was still being sought.