Mobile backhaul used to be simple for mobile operators; they bought T1/E1 leased lines to backhaul voice traffic from cell sites and when they needed more capacity they bought new lines. The mass adoption of mobile data by consumers and businesses, however, has shattered that comfortable equilibrium and mobile operators have been forced to look to new technologies to support their rapidly growing backhaul needs.
A recent report from analysts ABI Research warns that mobile operators need to urgently upgrade their backhaul networks if they want to deliver anywhere near the promised bandwidth offered by high-speed packet access (HSPA). “Backhaul is a major contributor to network performance and cost, and operators should design their networks to meet peak traffic demand – not just average usage levels,” says ABI Research senior analyst Nadine Manjaro.
ABI Research says that as T1/E1s reach near capacity, network performance degrades by over 40%. Rapidly rising mobile data traffic therefore has an immediate impact on network performance and this is exacerbated by long provisioning times for leased lines.
Beating rising costs
Operators aren’t just suffering from performance issues - backhaul is also an increasingly costly problem. According to ABI Research, T1/E1 and microwave backhaul was the largest contributor to operator capital and operational expenditure (CAPEX/OPEX) in 2007. Spending on backhaul is also rising inexorably with global CAPEX spending expected to increase from $14 billion in 2007 to $23 billion in 2012. OPEX will also rise from $1 billion to $6 billion during the same period.
To keep a lid on these rising costs, it is essential that operators look to backhaul solutions that meet their performance requirements and minimise CAPEX and OPEX. Many industry analysts recommend that operators focus on using Ethernet-based solutions for backhaul, including Ethernet over fibre and Ethernet over copper. Some operators are already starting to use hybrid infrastructures, which use Ethernet or DSL for data backhaul while keeping voice on the TDM infrastructure using T1/E1.
“In 2012, there will be a more distributed mix of backhaul technologies across the various options,” says ABI Research’s Manjaro. “Microwave is expected to be the primary backhaul solution in all the regions studied, except Latin America and North America. Ethernet over fibre will be a very popular choice for upgrades between now and 2012, primarily due to its lower cost per megabit and high data rate, compared with other backhaul options.”
Encouraging standards
Ethernet has been boosted by work carried out by the Metro Ethernet Forum (MEF) to improve quality. “Operators were previously reluctant to hand off their radio traffic to anything other than a dedicated T1/E1 link, where they had confidence in the quality and availability of the circuit,” says Glen Hunt, principal analyst in carrier infrastructure at Current Analysis. “The MEF’s efforts have now built credibility for Ethernet as a transport and service delivery infrastructure.”
Another key development driving Ethernet-based mobile backhaul is the standardisation of pseudowire technology. This allows operators to carry multiple types of traffic over the same infrastructure. For backhaul this means that operators could carry TDM-based voice traffic and IP-based data traffic over the same Ethernet infrastructure.
Ultimately, the flexibility of Ethernet as a backhaul technology will hold mobile operators in good stead for the switch over to an all-IP infrastructure. Although this is likely to happen first in the core, Ethernet will allow operators to make the switch without any need for costly infrastructure changes.
For further information on infrastructure upgrades contact Imtech Telecom .