Did you attend MWC and not stop by the Backhaul Pavilion? Don’t worry if you missed it, since there was no such place at the Barcelona event! But thanks to my backhaul-focused attendance, I am here addressing what in my opinion was one of the hottest topics within the wireless backhaul market: all-outdoor radio configurations (AOR). Development of AOR solutions is being driven by industry consensus around the need for small cell deployment as complement to traditional macro cell deployment. Small cells will feature integrated all-outdoor form-factors, thus requiring equally integrated backhaul so as not to lose the advantage of low-cost and fast zero-footprint installation. Although the issue of whether to develop AOR has been lurking for years in the microwave market, this year’s MWC seems to be a turning point for all vendors to agree on the need to release AOR products as soon as possible.

AOR configuration has a strong relationship with the evolution of networks from TDM to pure-packet. Since the small cell revolution is coming in an age when TDM lines are old-fashioned, there is no sense in providing TDM support in either the small cell or its associated backhaul connection. Therefore, most AORs that are already on the market, or plan to arrive shortly, are pure-packet – even when their manufacturers still forecast hybrid backhaul to be the predominant equipment flavor. This is the case of Ericsson’s PT series and Aviat Networks’ WTM 3000, both released during the show, although their respective hybrid products continue to be the most in-demand for now. The continued demand for hybrid backhaul has caused some vendors, such as NSN, to reconsider their initial positions. NSN is now also supporting hybrid operation in its flagship FlexiPacket radios, which last year offered exclusively pure-packet operation.

Small cell backhaul is not the only application for AORs. In developing countries or rural areas with little infrastructure in place, cost reduction is always appealing. Avoiding the installation of cabinets allows not only for reduced CAPEX, but also for reduced OPEX, since air conditioning, heaters or external networking equipment are then expendable. It is interesting to note the need to manage harsh environmental conditions is precisely what makes developing an AOR platform challenging, since Ethernet networking hardware (and particularly its fiber-based version) is not generally prepared for tough working conditions.

However, assuming vendors can integrate everything into a single ruggedized enclosure, there is not a single wireless technology that fits this AOR use case. With the exception of DragonWave and Ericsson, microwave vendors continue to be focused on frequencies below 44 GHz, being still a bit reluctant to develop higher frequency solutions although they recognize the business case for doing so in the long term. DragonWave’s Quantum Compact+ and Ericsson’s PT series have been expanded to 60 GHz and 80 GHz, respectively. The former also features built-in XPIC (cross-polarization interference cancellation) without requiring any additional equipment besides the two radio units.

In addition to microwave and millimeter wave, non-line of sight (NLOS) solutions are starting to emerge. Small vendors such as Taqua and Blinq Networks, both present at MWC for the first time, are pioneering this market by developing WiMAX-based AOR solutions. Thanks to its maturity, the WiMAX ecosystem covers both 2.6 and GHz 3.5 GHz bands – the main ones where NLOS backhaul applications are suitable. TD-LTE, which like WiMAX is OFDM-based, is also suitable for this kind of application, as Vodafone demonstrated with a TD-LTE AOR from Huawei providing backhaul to an FDD-LTE small cell from the same vendor. TD-LTE’s offers a larger long-term ecosystem for backhaul applications compared to WiMAX, although only covering the 2.6 GHz band. NLOS backhaul thus represents an interesting second opportunity for many WiMAX vendors who have seen their business decline over the last few years. Point-to-multipoint (PmP) configurations are increasingly being considered by network planners through NLOS backhaul, which can co-laterally benefit PmP microwave vendors such as Intracom Telecom and Cambridge Broadband.

The traditional fiber versus microwave backhaul battle is slowly giving way to a more complex mixture of fiber and wireless technologies, highlighting that no single technology will be capable of covering all the backhaul use cases. This AOR trend and some other interesting ones will be further analyzed in Maravedis’ Wireless Backhaul from an All-IP Perspective report, 2nd Edition, to be published in April.

MARAVEDIS is a leading analyst firm focusing on 4G and broadband wireless technologies and markets.

Author: Esteban Monturus, Market Analyst - Europe & Backhaul