The expansion of 5G mobile networks is moving at full speed, while wired and wireless gigabit-rate fixed access systems deployment accelerates in the wake of the recent pandemic. As telecommunications traffic grows relentlessly, mobile and fixed network operators continuously work at enhancing their transport systems. In the last couple of decades, the majority of telecommunication network traffic has shifted from “narrowband” TDM to broadband packet-based Ethernet/IP. Wired and wireless transport solutions have adapted to accommodate this shift.
Microwave radio systems have been an important part in the transport network technology mix and are expected to continue to be in the foreseeable future, as fiber cannot be optimally deployed everywhere.
Native packet radio systems are most suitable for the IP/Ethernet traffic that dominates modern communication systems, fixed and mobile. Such radios exploit automatic adaptation of the radio transceiver's modulation types (modulation format, coding and bandwidth) to enable robust continuous link operation at the corresponding various capacities of each modulation type. The radios shift their supported modulation types, in a fast and errorless way, from the maximum-capacity modulation type, which is operational for most of the time during dry weather conditions, to the more robust minimum-capacity modulation type, at times of rain precipitation, going through all the supported modulation types in-between. As link capacity decreases the radios continue to transport the data traffic on a higher-priority basis.
The radio planning of such links exploits the concept of differentiated availability, according to which the link is designed for the optimum service availability of four or five 9's (i.e. 99.999%) for the minimum necessary capacity, while being able to operate at the maximum capacity at a lower, but satisfactory, availability between two to three 9's.(i.e. for the vast majority of the time).
This results in significant reduction of the link’s antenna size and/or required spectrum compared to the case in which the link design would require maximum availability at the maximum link capacity. This leads to significant reduction in the link’s infrastructure and space requirements, as well as to capex and opex savings. Such treatment has been shown to maintain the quality of experience of a mobile network’s end customers.
Combining radio links operating at lower RF spectrum frequency bands, which are capable of bridging longer distances, with links operating at higher frequency bands, which are capable of providing higher capacities, is a most effective method to deliver high capacity and long range connectivity. A number of names is used for such a technique in the industry, such as “Dual Band” when two bands are combined, “Band Carrier Aggregation”, “Multi-Band” and others. When the combination of the links is based on L1-link aggregation/ Radio Link Aggregation (RLA), this multi-carrier/band scheme further extends the concept of adaptive modulation and allows radio link planning based on the differentiated availability concept.
The capacity of a Dual Band link, which is the sum of the capacity of the links of its constituent links, is dominated by the capacity of the higher-frequency band link at favorable weather conditions for 99% to 99.9% of the time.
For 99.9% to 99.99% of the time the combined capacity may be composed of comparable contributions from the links of both bands. Finally, for the last few thousandths of availability percentage points the Dual Band link reverts to the operation of the lower frequency band link only. The modulation format and the between-band transitions happen in seamless way eliminating service interruption to the priority traffic when the capacity is downshifting. As the weather improves the Dual Band link comes smoothly back up to full capacity.
The Dual Band scheme can be applied to brownfield (existing) Microwave link (MW) deployments to offer capacity upgrade to the existing links. This may require ability to combine radios of different vendors in a simple and effective way both in terms of radio operation as well as of the antenna. The Dual Band scheme can also can be used for Greenfield deployments to design high-capacity longer-range links.
Currently one of the most important band combinations, delivering the required transport capacity for 5G networks, is that between MW systems operating at or below 23 GHz and E-Band radios. E-band radios operating in the 71-76/81-86 GHz part of the spectrum have proven to be the effective and necessary radio solution for the 5G-era network transport. Their importance as a transport solution for the 5G-era has been recognized by the global telecommunication community at WRC-19. E-Band technology operating at the maximum channel size of this band offers abundant capacity, typically 10 Gbit/s and up to 30 Gbit/s.
The physics of electromagnetic wave propagation in the earth’s atmosphere dictates that operating at higher frequencies results in smaller link ranges. Typically E-Band links are deployed by operators for backhaul at 2-5km link ranges depending on factors such as, the climate conditions in the deployment area, the required availability of the link’s operation and the system gain capabilities of the particular E-Band system. Maximum benefit can be derived for E-Band-only, as well as E-Band-based Dual Band deployments when the E-Band link features the highest possible system gain at high capacities. It is the E-Band system gain at high/maximum capacity that will determine the effectiveness of the scheme as a link and capacity range-extender. By using high gain E-Band radios an operator can extend high capacity connectivity to ranges of 10km or more.
For example, the figure below compares the ranges, for availabilities between 99% and 99.9%, of an average market E-Band solution with a 64dB system gain at 10 Gbit/s with a solution, such as the UltraLink™-GX80, with a leading system gain exceeding 70dB at 10 Gbit/s. The design assumes an E-Band channel size of 2000MHz, an antenna size of 60cm and operation in ITU-R Rain Region K. This region’s rain rate matches or exceeds the rain rate applicable to the entire Europe, Canada and most of the U.S.A.
The figure shows that, in the context of a Dual Band solution, the network operator can enjoy up to 30-40% longer link range for the delivery 10 Gbit/s capacity for more than 99% of the time by using a high-performing E-Band radio. Similar benefit can be obtained for smaller channel sizes and the corresponding maximum capacities. MW systems can today easily contribute 1-2 Gbit/s using one or two radios in XPIC configuration. Adding the MW capacity to the E-Band capacity can further enhance the percentage of time when the 10 Gbit/s capacity is available.
Intracom Telecom's UltraLink™ E-Band radios, already widely deployed in MNO and WISP networks, are ideal for 5G-era transport / xHaul applications, as they are at the forefront of performance in terms of link range, spectral efficiency and operational flexibility. The UltraLink™-GX80, offering a leading system gain of more than 70dB at 10 Gbit/s capacity, supports Dual Band configurations in seamless combination with Intracom Telecom’s OmniBAS™ fully outdoor or split mount MW radios using Radio Link Aggregation. OmniBAS™ radios can contribute up to 2 Gbit/s capacity in 2+0 XPIC/RLA configuration in a Dual Band configuration.
Importantly, UltraLink™-GX80 can even be combined with third party vendor radios to enable capacity enhancement of existing MW links in a more effective and economical way, compared to adding one or more MW links. Furthermore, Intracom Telecom can offer a dual band antenna capable of supporting both third party vendor MW radios, as well as the UltraLink™-GX80 greatly facilitating the deployment of such a Dual Band solution.
As a result, UltraLink™-GX80 radio offers an excellent solution for providing the highest performance Dual Band links.