|Topic:||Self-organising networks for mobile backhaul|
Prasanjeet Khuntia is Country Head of Tellabs India. In his current role, he develops and directs Tellabs’ business strategies in India, Bangladesh and Sri Lanka. Formerly an engineer from REC Rourkela, Mr Khuntia worked at Tellabs as Sales Manager in the past, after which he joined Cisco as Business Development Manager.
Prasanjeet Khuntia holds an MBA from the Indian Institute of Management in Calcutta.
Service providers must reduce operational expenses, innovate, and deploy the latest technologies to grow revenue and keep the customers happy. By using self-organizing networks (SON) in mobile backhaul networks, operators reduce costs by automating routine and repetitive tasks. SON helps speed rollouts, improves bandwidth usage, optimises power usage and reduces training requirement. SON, together with network management systems (NMS), helps mobile operators recover from service outages automatically. SON can also ease transitions from legacy mobile networks to LTE.
One of the key trends in recent years has been the growth of mobile broadband subscriptions globally. As per industry experts, mobile broadband subscriber has been growing at the rate of over 40 per cent in 2011, crossing the one billion mark. According to Infonetics research, the number of mobile phones is on track to exceed the global population by 2016, with data traffic growing at the rate of over 40 per cent annually. Operators been deploying the latest technologies to create new revenues and address the consumer demand for higher data traffic. Deployments of LTE networks are increasing globally, with the US leading the deployments. Other parts of the world, like India, where LTE services were launched in mid-2012, are following the US trend. Despite the heavy investments and LTE launches, 2011 ARPU fell in every region of the globe.
This highlights the age-old dilemma: How can service providers reduce operational expenses while staying innovative, deploying the latest technologies to grow revenue and keeping the customers happy?
With the demand for bandwidth in mobile networks growing exponentially, the backhaul network easily becomes a bottleneck for the increasing video, data and voice traffic. At the same time, the transition from TDM (time-division multiplexing) to packet technologies, with the aim to drive the cost per bit down has increased the backhaul network complexity. Increased complexity is most certainly taking a toll on the mobile operator’s ability to remain profitable. Under these conditions it is challenging for network operators to roll out LTE /3G networks and increase the backhaul capacity quickly enough to keep up with customer demand as well as to do that in economically sustainable manner.
Introducing self-organizing networks (SON) in mobile backhaul networks enables operators to reduce costs by automating routine tasks. Increased automation helps to optimize the work, but gives operators full control of when to use that automation. Overall, SON supplements the ‘intelligence’ applied to traditional network management by focussing on automating repetitive and routine tasks – the most significant, time consuming, part of daily operational work.
The use of SON to automate mobile networks is not new. The Third Generation Partnership Project (3GPP) and the Next Generation Mobile Networks (NGMN) alliance first proposed the SON standard. The first major announcement about SON functionality in a LTE mobile network was made at the Mobile World Congress (MWC) in 2009. The SON standard is now at Release 8. The leading mobile infrastructure vendors began delivering SON-capable mobile radio equipment in 2009 and many network operators are benefiting from the SON deployments.
SON in mobile backhaul networks
Introducing SON in 3G/LTE/Het-Net mobile backhaul networks can help operators to significantly reduce both capital and operational expenditures:
• CAPEX savings: – SON in mobile backhaul can help in better network planning and optimize the use of capital.
• OPEX savings :
o Faster roll-outs
o Plug and Play installations : installation personnel do not need special skills or tools
o Managed bandwidth efficiency
o Managed capacity through intelligent and automated traffic engineering
o Power optimization features like remotely powering off of cell sites during low traffic hours.
o Significant reduction of manpower training requirements, as a result of automation in deployment, optimization and maintenance activities.
When using SON in RAN (radio access networks), operators have reported 40 per cent faster rollouts, and a 90 per cent reduction in daily maintenance for LTE networks; similar benefits can be expected with SON in both LTE and 3G backhaul networks.
The four key areas where the SON in mobile backhaul can contribute significant OPEX Savings are
1. Network planning
When scaling up to meet demand, network planning is possibly the most critical aspect of network operations. Traditional methods of network planning are very human-dependent, and so necessarily include the risk of human error. SON technologies can reduce this risk significantly through intelligence and automation. For example, operators can pre-plan network elements, topology, connectivity and services and save the configurations in a database.
Plug and play installation is a significant advantage of SON. With this feature, installation teams do not require any special skills or tools.
The pre-planned configurations can subsequently be transmitted to the network elements as they are installed, making the simultaneous rollout of hundreds of RANs not only possible, but faster and less error-prone. In addition to automated configuration, SON-capable networks can also test connectivity to the cell sites to check if they meet SLA (service level agreement) standards, discover neighbouring network elements, update software and notify the mobile operator, over SMS or email, that a deployment is successful and complete.
More efficient bandwidth allocation is not only important for subscribers’ quality of experience (QoE), but also to reduce operational expenses. With SON networks, it is possible to easily move capacity to wherever one needs it because of the automated correlation between backhaul network analytics and information retrieved from the RANs. This intelligence in the network, and control over traffic management also means that operators have the ability to re-allocate resources to head off potential network and/or service disruptions.
Another way that SON-capable networks can save operators money is to remotely power off cell sites during low-traffic hours and boost power as needed. Although this does not appear at first to be a significant benefit, consider this – town centres see a lot of network traffic during office hours on weekdays, requiring considerable capacity, but on weekends and at night, traffic is probably quite low or even non-existent. The ability to power off, or adjust power to base stations remotely, cuts expenses; the savings can add up to quite a sum by the end of the year.
Fault monitoring and management are familiar aspects of network management systems (NMS), but with SON-capable NMS systems there may be closer integration with other aspects of the network, such as more comprehensive control and monitoring of remote network elements. In addition to greater visibility into the performance of individual network elements, SON-capable NMS will be able to help mobile operators to recover from service outages either by ‘failing over’ [an automatic switchover to standby backup systems in the event of failure] to neighbouring network elements, or even activating automated troubleshooting features in the NMS.
Mobile operators have significant existing investments in legacy mobile technologies and, in today’s economy with downside risks in Europe and Asia and a slow recovery in the USA, the move to LTE and SON is expected to be a lengthy process. Although many operators see the need to move to the SON framework eventually, they still have to support their legacy infrastructure. Most mobile operators will run LTE alongside their 2G, 2.5G and 3G networks, which gives rise to heterogeneous networks that can be difficult to monitor and manage. Some NMS systems may require large-scale upgrades with large parts of the existing network overhauled – a so-called ‘forklift upgrade’ – which can possibly disrupt current operations and add significantly to costs. Because heterogeneous networks, or ‘het nets’, are a reality, mobile operators will want to look for NMS solutions that integrate with most, if not all, generations of mobile technology in the network.
A heterogeneous network does not necessarily mean fragmented backhaul systems with different management systems for each mobile generation running simultaneously. Operators will seek homogenous backhaul solutions that not only support previous and current mobile generations, but also impose few if any restrictions on RAN equipment vendors, to retain flexibility when making future purchases. It is also important that the backhaul network support not only current fibre transport speeds but foreseeable future media technologies as well. Mobile backhaul with SON in makes this possible.