The seemingly ceaseless demand for data is pushing microwave backhaul to its limits as there is not enough available bandwidth for microwave links to backhaul all the data from the base stations/access points (BTS/AP). Traditional microwave bands are, due to regulatory reasons, often limited to bandwidth of 56 to 112 MHz for each channel available for a point-to-point backhaul link. Hence, microwave links offer typically up to 1 Gbps backhaul using very high modulation schemes like 4096-QAM. Even if the modulation in the next generation microwave links were increased to 8192 QAM, the capacity would only rise by 8 percent.

It is increasingly being recognized that millimeter wave-based communication is a possible solution, as it can support 5 to 10× larger throughput than microwave links. In the U.S., the Federal Communications Commission (FCC) recently added a 7 GHz license to the license free V-Band, which now includes a 14 GHz band ranging from 57 to 71 GHz.  By using only 1 GHz bandwidth and 64 QAM modulation, at least 4 to 5 Gbps can be achieved.

To address this market Sivers IMA has introduced the highly integrated TRX 1608-LT6275 transceiver for millimeter wave applications that is claimed to offer a price-performance ratio, which should be of interest to all data and telecom point-to-point radio link vendors. It also has the potential to cut their time to market for a V-Band link by at least 18 months compared to making their own transceiver chip.

The circuit, shown in Figure 1, includes a complete millimeter wave transceiver, digital control, signal source and a complete analog baseband. This third party millimeter wave transceiver fully supports for the market leading 85100 millimeter wave baseband/modem from MaxLinear (formerly Broadcom). By having fully integrated analog baseband (BBTx and BBRx) support, a better total cost of ownership for the wireless backhaul is available.

There are various point-to-point use cases where the TRX 1608-LT6275 can be utilized. As illustrated in Figure 2, these include a broad portfolio such as: macro cell backhaul, small cell backhaul, Remote Radio Head (RRH) fronthaul for C-RAN, Fixed Wireless Access (FWA), Wireless Gigabit to Home (GBTH) and video surveillance backhaul applications.

Thanks to advanced Silicon Germanium (SiGe) technology and a very high fmax of 300 GHz, high output power and low noise figure can be achieved. The packaged chip includes all building blocks such as millimeter wave 57 to 71 GHz up and down-converters, Power Amplifier (PA), Low Noise Amplifier (LNA), x6 LO Switch, Programmable Gain Amplifier, Voltage Controlled Oscillator (VCO) and analog baseband (BB Tx and BB Rx).

The front-end millimeter wave technology is silicon proven and qualified in Sivers IMA’s second generation converter modules. The integrated VCO provides excellent phase noise to support up to 64 QAM modulation. Optionally, an external LO can be injected, enabling user selectable LO and even higher modulation.

Significantly, the SiGe transceiver chip has been integrated into a 7 mm × 7 mm embedded Wafer Level Ball Grid Array (eWLB) packaged device, which offers excellent millimeter wave performance at 57 to 71 GHz together with production friendly packaging technology—for easy surface mounting on printed circuit boards. All process steps on the eWLB package are performed on the wafer, which results in a small and flat package with excellent electrical and thermal properties.

Additionally, this millimeter wave solution also offers the possibility to develop smaller antennas with decreased cost as well as the size of the final product, which are very important aspects for all telecommunication infrastructure.

Sivers IMA AB
Kista, Sweden
www.siversima.com