In LTE, QoS configuration during signaling involves specifying QoS parameters for bearers that control how traffic is handled in the network. This configuration is done through the exchange of signaling messages between the UE (User Equipment), the eNodeB, and the core network components like the MME (Mobility Management Entity) and the Serving/PDN Gateways. Here's a simplified overview:
- Bearer Establishment: When a user connects to the LTE network, a default bearer is established with basic QoS settings. This process involves signaling messages that include QoS parameters, such as the QoS Class Identifier (QCI) which defines the level of QoS (e.g., priority, packet delay budget, and packet error loss rate).
- Dedicated Bearer Setup: For services requiring specific QoS, such as VoIP or video streaming, a dedicated bearer is established. This involves signaling messages like the "Bearer Setup Request" that carry QoS parameters, including QCI and Allocation and Retention Priority (ARP). ARP determines the bearer's priority and its pre-emption capabilities.
- QoS Parameters in Signaling Messages:
- QoS Class Identifier (QCI): Indicates the type of QoS treatment (e.g., prioritization, delay, reliability) that should be applied to the bearer's traffic.
- Allocation and Retention Priority (ARP): Specifies the priority of the bearer, influencing its retention and allocation in congested conditions.
- GBR (Guaranteed Bit Rate) and MBR (Maximum Bit Rate): For GBR bearers, these parameters define the guaranteed and maximum data rates, respectively.