Optimizing Critical Communications: The Role of QoS, Priority, and Preemption in MCS

Introduction

Critical industries like public safety and transportation demand unwavering communication reliability. Mission Critical Services (MCS) built on 3GPP standards offer the low latency and high reliability these sectors require, prioritizing critical voice, video, and data over commercial traffic.

3GPP-based Mission Critical Services (MCS) can provide these industry users with low latency and highly reliable voice, video, and data communications. Separating mission-critical data from non-mission-critical data through the MCS core network ensures that industry user traffic is always prioritized over commercial traffic.

But how exactly does MCS guarantee priority access to critical communication data? How does it manage the allocation of broadband network data resources? Can industry users seize the broadband network data resources of other commercial users?

To answer these questions, it is first necessary to introduce three critical characteristics of MCS: Quality of Service (QoS), Priority, and Preemption.

Quality of Service (QoS) is a collection of techniques for managing the available bandwidth, delay, jitter, and packet loss of data streams in a network. When the network is overloaded or congested, QoS ensures the normal transmission of important service traffic. QoS enables operators to differentiate between different services and users, optimize the use of network resources, and maximize the value created per unit of network capacity in the case of limited resources.

Priority is a network capability that precedes one user's applications or network access over another's. By setting a higher priority value, important data traffic with strict response time requirements is not delayed.

Preemption is a network capability that allows high-priority traffic from public safety departments or first responders to take over the data resources of low-priority traffic. In a critical situation, low-priority traffic may be moved to a different frequency band or temporarily disconnected from the network.

Think of it like a highway system: QoS is the traffic management, ensuring efficient flow. Priority determines which vehicles (data) get to use the fast lanes, while preemption lets emergency vehicles (critical communications) override other traffic during crises.

When road congestion occurs, road management rules must be set to ensure smooth traffic and improve resource utilization. These rules are equivalent to the QoS mechanism. QoS can mark vehicle types, such as special vehicles (police cars, ambulances, fire trucks, disaster relief vehicles), public transportation buses, and personal vehicles, and prioritize special vehicles. "Identifying the vehicle" involves classifying transmitted network service data and identifying the resource type, priority, delay, packet loss rate, and other quality requirements for each type of service, also known as QCI (QoS Class Identifier). "Giving priority" is also known as Guaranteed Bit Rate (GBR), ensuring that high real-time requirement services maintain the corresponding bit rate even under network resource constraints.

Mission-critical communications require prioritized access to services at the moment of need to reduce response latency. Therefore, MCS is assigned GBR-type QCIs, prioritizing them to be delivered on high-quality service highways, while non-GBR commercial traffic is on lower-priority state highways (priority).

When congestion occurs on the freeway, i.e., when the high-priority queue also experiences a lack of resources, special vehicles with higher priority can use the emergency lane to preempt the priority of other lanes (preemption).

Quality of Service, Priority, and Preemption are broad concepts that cover numerous 3GPP features and functions. MCS ensures that users in industries such as public safety have priority access to the broadband network when needed. QoS allows the management of available network bandwidth, ensuring that important network services are prioritized. It assigns GBR for mission-critical voice (MCPTT), mission-critical video (MCVideo), and mission-critical data (MCData) of QCI, meeting end-to-end latency and packet loss requirements and guaranteeing critical voice and data services at all times.

Hytera HyTalk MC: A 3GPP-Compliant Solution

Hytera's HyTalk MC solution fully complies with 3GPP MCS standards, providing a complete end-to-end QoS mechanism for reliable, prioritized critical communication. Available 24/7, HyTalk MC ensures mission-critical voice, video, and data services are always accessible when they matter most.