5G drives higher speed, lower latency and greater capacity than 4G LTE networks, making it critical across industries globally. We have just started scratching the surface of the type of new use cases that become possible through 5G’s innovation potential. While the rollout of 5G is accelerating, we’re still witnessing different geographies and telecom operators deploying 5G networks at a different pace — especially as meeting its requirements is costly and complicated. 5G should be an innovation driver and not another source of digital divide among regions and markets.
The 5G infrastructure market is growing rapidly with a CAGR of 60% and is estimated to reach a total market size of about $50 billion by 2027. 5G networks are evolving to enable new mission-critical applications, including AI and robotics, Industrial Internet of Things (IIoT), autonomous vehicles and a multitude of connected devices and sensors. 5G deployment comes with stringent requirements, especially around time synchronization. Any failure to deliver precise and accurate time synchronization leads 5G services to systemic failure. A faulty synchronized base station can cause significant disruption as it interferes with the 5G operations of other operators and creates broader problems across networks.
It’s critical for telecoms operators globally to deliver accurate and secure 5G synchronization across their networks. So far, this requires significant investment which raises 5G rollout costs dramatically. According to a report by Kearney (April 2020), the synchronization cost is estimated between 3-5% of the total 5G network rollout cost, i.e., $1.5-2.5 billion in 2027 and can in many cases require a large forklift upgrade of old infrastructure to enable PTP network synchronization. As not all telecom operators are able to sustain these costs, this can put some markets and industry players at a significant competitive disadvantage.
To level the playing field and ensure all operators can be part of the 5G revolution, they need to leverage technology solutions that can help them upgrade their network infrastructure to meet synchronization requirements quickly, securely and cost effectively.
Why is 5G network synchronization important?
Network synchronization is key for mobile networks. The mobile network infrastructure delivers higher capacity and speed to serve an array of new applications and services. While the requirements for 4G/LTE network synchronization were already demanding, 5G takes them a step further.
With 5G TDD (Time Division Duplex) technology becomes more important and requires a much tighter synchronization, compared to FDD (Frequency Division Duplex) which is prevalent in most 4G/LTE networks. Moreover, new features and advanced network techniques such Massive MIMO, Carrier Aggregation (CA), License Assisted Access (LAA) and Coordinated Multi-Point (CoMP) transmission and reception technologies require further synchronization improvements. The synchronization requirements cover both neighboring base stations and devices across the network.
The vulnerabilities of GPS-based synchronization
As part of the 4G paradigm, mobile networks delivered synchronization to base stations and small cells with Global Navigation Satellite System (GNSS) such as the Global Positioning System (GPS) and Precision Time Protocol (PTP).
GNSS solutions deploy GPS receivers together with the base station antennas. On the plus side, GNSS technology delivers highly accurate network synchronization. However, this comes with a set of compromises. The densification of mobile networks with many small cells raises the cost of GNSS-based solutions. These solutions are also vulnerable asit is easy to jam out GNSS signals, either by blocking them out completely (“jamming”) or by replacing the GNSS signal with a similar but incorrect signal (“spoofing”). This is a topical conversation in the telecoms industry, especially due to the current geopolitical situation with the Russian invasion of Ukraine. To this end, the European Union Aviation Safety Agency (EASA) issued a safety information bulletin on March 17, 2022, warning of GNSS outages leading to navigation/surveillance degradation that have intensified in geographical areas surrounding the conflict zone as well as in other areas. At the same time, individual country regulators such as the Swedish Post and Telecom Authority (PTS), are explicit that a GNSS-independent solution to transport synchronization is a mandatory requirement for operating the 5G network.
5G mobile networks also bring increased demands on cell density, indoor cell coverage and deployment in challenging geographical areas, including tunnels, buildings and factories where satellite visibility is challenging. Likewise, geography and landscape impacts GPS-dependent solutions that find it hard to deliver in areas with limited satellite visibility, such as urban areas where buildings obstruct the view and rural areas with deep forests and canyons.
PTP solutions raise costs
An alternative method to GNSS 5G synchronization solutions is network-based timing based on packet switching technology, mainly Precision Time Protocol (PTP or IEEE1588v2), supported by Synchronous Ethernet (SyncE). PTP solutions don’t share the same disadvantages as GNSS-based timing in terms of safety, robustness and ease of deployments. However, there are still considerable challenges when introducing support for PTP and/or SyncE in mobile networks. The investment cost is a key downside as the transition to network-based timing requires either a full overhaul or significant upgrades in hardware equipment and software since PTP requires every node to provide on-path PTP support (in HW) to ensure 5G timing accuracy. This means that several operators will not be able to complete these network upgrades and consequently will fall behind the race to rollout 5G.
While the aforementioned are the main 5G synchronization models, there are further synchronization technologies that could be considered for 5G mobile networks. For example, White Rabbit combines PTP and SyncE and introduces additional mechanisms to improve synchronization accuracy. White Rabbit is specifically designed to meet the stringent requirements for particle accelerators and is typically used in dedicated fiber or LAN environments. However, White Rabbit requires dark fibers between dedicated timing nodes, which makes such solutions too costly for national rollouts. A further alternative approach is Over-the-Air Time synchronization (OTA), which is designed for ultra-reliable and low-latency communications (URLLC). OTA is a radio interface-based synchronization solution that has been used for synchronizing base stations in 4G/LTE and is an alternative that is put forward for 5G mobile networks in the RAN (Radio access Network) but does not scale for the backhaul and WAN network.
The future of 5G synchronization
Time synchronization is becoming critical for many market segments, including power networks, synchronization of distributed databases, stock exchange trading, distributed video production and defense networks. The synchronization challenge is highly relevant for most real-time critical network installations, including digital terrestrial television (DTT) networks with stringent frequency and phase synchronization, within a ~1 µs requirement.
To address this challenge, the Precision TimeNet (PTN) solution has been developed and deployed in DTT networks in 15 countries and was recently chosen by Turk Telekom for its 5G rollout. Precision TimeNet provides distribution of absolute time with very high accuracy over the existing IP network. This solution disaggregates time distribution from the transport and thus does not require all nodes to be upgraded for on-path PTP support. This means that it may significantly reduce CAPEX and OPEX, as well as, speed up rollout times. Synchronization becomes a virtualized network function across the IP network. It thus creates a virtual synch network over the existing IP network, distributing time (phase) from clock sources such as atomic clocks out to base stations or the radio access network while managing all redundancy, security and asymmetries in the IP network. The Precision TimeNet solution has been augmented with software for running over public managed IP networks with advanced filtering, multilink collaborative clocks and asymmetry profiling to enhance reliability and improve accuracies. A key benefit of the PTN solution refers to its openness and interoperability, enabling operators to integrate it within their existing network infrastructure. It’s complementary to GPS-based solutions, addressing their security challenges, as well as fully interoperable with existing PTP installations
The solution enables geographically disadvantaged regions such as rural areas to access good bandwidth and contribute to closing up the digital divide by removing the cost of replacing the entire underlying network infrastructure to enable 5G deployment. PTN is also an environmentally sustainable solution as it reuses existing communication equipment, minimizing the telecom network footprint.
Mobile network innovation changes what’s possible
5G has the potential to change the world as we know it bringing unapparelled potential to telecom and mobile communications. While the business world is relying on 5G to enable more innovation, new revenue streams and growth opportunities, there are still some key hurdles that need to be overcome. The costs of 5G synchronization of network infrastructures are significant and can be prohibitive for several telecom operators.
Precision TimeNet redefines what’s possible in 5G synchronization. It leverages existing telecom networks without requiring additional CAPEX. In doing so, it delivers the accuracy, security and low latency operators need to deploy 5G today. It also delivers the openness and interoperability the operators need to integrate it within their current infrastructure, driving efficiencies across the board. Removing the cost and complexity hurdles associated with the 5G rollout paves the way for telco operators globally to transition to 5G sustainably and efficiently. GPS-independent solutions support turning the vision of 5G into a reality and it’s time for operators to harness its benefits today.
