PaperlayerView exact revision on arXiv

Source-linked AI summary

Implementation of Hybrid QoS-Aware Data Radio Bearer in 5G Networks

Padmapriya Patil, Abhishek Bhattacharyya, Gudepu Venkateswarlu, Andrea Fumagalli, Koteswararao Kondepu

arXiv:2610.03209v1cs.ET

TL;DR

Typical QoS flow-to-DRB mapping uses a single strategy per PDU session, limiting flexibility for heterogeneous traffic. This paper proposes and implements a 5QI-based hybrid mapping in OAI, sharing compatible flows while dedicating DRBs to delay-critical traffic. The reported implementation validates the mapping and describes improved throughput for GBR traffic and isolation for Delay-Critical flows.

  • Problem

    Typical implementations use one QoS flow-to-DRB mapping strategy per PDU session, limiting flexibility under dynamic, heterogeneous traffic.

    Source: §I · p. 1

  • Method

    The OAI implementation maps flows by standardized 5QI, sharing compatible GBR and Non-GBR flows while assigning dedicated DRBs to Delay-Critical flows.

    Source: §I · p. 1, A. Proposed Approach · p. 2

  • Results

    The OAI implementation validates the mapping; the paper reports improved GBR throughput and isolation for Delay-Critical flows.

    Source: §VI · p. 6

  • Takeaways & Limitations

    The framework supports multiple QoS flows within one PDU session while improving radio resource utilization, according to the reported experiments.

    Source: §VI · p. 6

Abstract

from arXiv · show

In Fifth-Generation (5G) wireless networks, Quality of Service (QoS) flow management supports diverse applications with heterogeneous QoS requirements, including latency-sensitive and high-throughput services. 5G architectures adopt a flow based QoS framework, where QoS flows are mapped to Data Radio Bearers (DRBs) to achieve the desired radio resource allocation. Existing mapping strategies typically rely on static one-to-one QoS-to-DRB mappings per PDU session, leading to inefficient spectrum utilization or inadequate support for delay sensitive traffic. This work presents a hybrid QoS-aware DRB mapping mechanism based on standardized 5G QoS Identifier (5QI) characteristics. The proposed framework incorporates multiple QoS flows within a single PDU session, supporting both many-to-one and one-to-one mapping strategies. The hybrid framework improves radio resource utilization and reduced bearer overhead by enabling flexible DRB utilization, where compatible non critical flows share DRBs while delay-critical flows are assigned dedicated DRBs to ensure strict QoS guarantees. The proposed hybrid QoS-aware DRB mapping is implemented using the open-source OpenAirInterface (OAI) mobile stack platform to demonstrate the integration of the proposed features within the existing 5G framework.

I. INTRODUCTION

5G’s flow-based QoS framework supports diverse service requirements, but typical single mapping strategies limit flexibility for heterogeneous traffic. This work proposes a 5QI-based hybrid mapping and implements it in OAI.

I. INTRODUCTION

  • Existing implementations typically use one QoS flow-to-DRB mapping strategy per PDU session, limiting flexibility under dynamic, heterogeneous traffic.The proposed mechanism combines many-to-one and one-to-one mapping based on standardized 5QI characteristics.Source: §I · p. 1
  • Compatible GBR and Non-GBR flows share a DRB, while Delay-Critical GBR and custom QoS flows receive dedicated DRBs to preserve strict QoS guarantees.The framework also supports adaptive isolation for delay-critical services when required.Source: §I · p. 1
  • The contributions include a hybrid 5QI-based mapping mechanism, an intelligent QoS flow grouping strategy, and an experimental OAI implementation.Source: §I · p. 1

A. Managing QoS Flows

5G identifies QoS flows with QFIs and standardized 5QI parameters, then maps them to radio bearers for differentiated treatment. Core-network policy and radio-layer functions participate in that path.

A. Managing QoS Flows

  • Each QoS flow has a QFI and standardized 5QI parameters, including priority, packet delay budget, and packet error rate.The SMF assigns QFIs; the UPF classifies packets and inserts the corresponding QFI into the GTP-U extension header.Source: A. Managing QoS Flows · p. 2

B. DRB Mapping

  • SDAP associates one or more QoS flows with DRBs; flows may share a DRB for resource utilization or use dedicated DRBs for latency-sensitive or isolated services.Lower protocol layers implement scheduling and retransmission policies according to QoS characteristics.Source: B. DRB Mapping · p. 2

C. QoS Flow in the Core Network

  • The PCF supplies 5QI-based policies to the SMF, which configures UPF packet classification and forwarding through PFCP rules.The UPF adds the appropriate QFI to downlink packets so the gNB can apply radio-layer QoS treatment.Source: C. QoS Flow in the Core Network · p. 2

D. Dynamic QoS Allocation in 5G

5G supports runtime QoS-flow changes within an active PDU session. PFCP and NGAP signaling convey updates that let the gNB alter flow-to-DRB associations while maintaining session continuity.

D. Dynamic QoS Allocation in 5G

A. Proposed Approach

The proposed approach replaces the baseline’s single DRB for all flows with a 5QI-based hybrid mapping. Its algorithm can enforce dedicated mapping or combine shared and dedicated DRBs according to flow class.

A. Proposed Approach

  • The baseline maps all QoS flows in a PDU session to one DRB regardless of QoS characteristics, potentially increasing contention among heterogeneous flows.The figure identifies the baseline architecture associated with this arrangement.Source: A. Proposed Approach · p. 2, Figure 2 · p. 3
  • When Delay-Critical mode is enabled, the algorithm creates a separate DRB for every QoS flow, producing one-to-one mapping.Source: A. Proposed Approach · p. 2
  • Otherwise, the algorithm classifies each flow by standardized 5QI, placing GBR and Non-GBR flows in the shared set and tracking Delay-Critical and unknown flows separately.Classification follows QoS characteristics defined in.Source: A. Proposed Approach · pp. 2–3
  • The algorithm creates one shared DRB for shareable flows and dedicated DRBs for Delay-Critical and unknown flows, then returns the completed mapping.Source: A. Proposed Approach · p. 3

IV. EXPERIMENTAL SETUP

The experimental testbed validates the proposed hybrid QoS-aware mapper in an OAI-based 5G environment. The implementation extends the stack to support multiple DRBs per PDU session and hybrid flow-to-bearer assignments.

IV. EXPERIMENTAL SETUP

  • The testbed comprises a 5G Core Network, gNB, and UE, with the modified gNB deployed using Docker Compose.The core-network functions run as independent Docker containers.Source: §IV · p. 3
  • The radio interface uses OAI's RF simulator, preserving the NR protocol stack for repeatable experiments without physical RF hardware.The text states that deployment on NI B210 or USRP N310 SDR platforms is possible without modification.Source: §IV · p. 3
  • The proposed mapper takes a set of QoS flows and a Delay-Critical mode flag, then returns their DRB mapping.The algorithm supports dedicated one-to-one mapping or shared many-to-one mapping according to the mode and flow requirements.Source: §IV · p. 4
  • The modified OAI stack supports up to 32 DRBs per PDU session, enabling hybrid one-to-one and many-to-one QoS-flow mapping.The changes extend the default single-DRB-per-session implementation across control and user planes.Source: §IV · p. 4

V. RESULTS AND DISCUSSION

Runtime logs and throughput measurements validate the implemented flow-to-DRB mapping and QoS enforcement. Compared with baseline OAI, the proposed framework uses multiple QoS-aware DRBs and is reported to achieve higher aggregate throughput and spectral efficiency.

V. RESULTS AND DISCUSSION

  • At the gNB, GBR and Non-GBR flows share DRB 1, while two Delay-Critical GBR flows receive dedicated DRBs 2 and 3.The observed creation of multiple DRBs is reported to confirm the implemented SDAP-based flow identification and hybrid mapping.Source: §V · p. 5, Figure 4 · p. 5
  • GBR and Delay-Critical GBR flows operate close to configured MBR values while meeting their GBR requirements during simultaneous downlink traffic tests.Table III summarizes configured QoS parameters and measured throughput.Source: §V · p. 5, Table III · p. 5
  • Multiple QoS-aware DRBs reduce contention among heterogeneous flows and provide higher aggregate throughput and spectral efficiency than baseline OAI's single-DRB approach.The comparison is summarized in Table IV.Source: §V · p. 5, Table IV · p. 5

A. Performance Evaluation Methodology

The evaluation compares the proposed framework with baseline OAI across three downlink traffic scenarios that progressively increase radio-resource contention, focusing on throughput and latency for a Delay-Critical GBR flow.

A. Performance Evaluation Methodology

  • Three downlink scenarios add background flows of 2 Mbps, then 4 Mbps, then 6 Mbps alongside a 5QI 82 flow configured with 4 Mbps GBR and 8 Mbps MBR.Each experiment lasted 60 seconds and was repeated five times; throughput is reported as sample means with 95% confidence intervals, and latency was measured for packet sizes from 64 to 1024 bytes.Source: A. Performance Evaluation Methodology · p. 5

B. Throughput and Latency Performance Evaluation

Under increasing background traffic, the proposed framework maintains the Delay-Critical GBR flow's throughput and low latency, while baseline throughput declines and latency rises with load.

B. Throughput and Latency Performance Evaluation

  • Approximately 7.41–7.42 Mbps is maintained across all scenarios by the proposed implementation, while baseline throughput falls from 5.40 Mbps in Scenario 1 to 2.69 Mbps in Scenario 2 and 1.85 Mbps in Scenario 3.The comparison concerns the 5QI 82 Delay-Critical GBR flow; the figure presents average throughput across the three scenarios.Source: B. Throughput and Latency Performance… · pp. 5–6
  • Baseline latency increases significantly as background flows increase, whereas the proposed framework maintains consistently low latency across scenarios.Both implementations show a slight latency increase with packet size; Table V reports end-to-end latency for different packet sizes.Source: B. Throughput and Latency Performance… · p. 6, Table V · p. 6
  • The reported throughput and latency results demonstrate traffic isolation and QoS preservation without changes to the underlying radio scheduler.The framework maps flows to shared or dedicated DRBs according to standardized 5QI characteristics.Source: B. Throughput and Latency Performance… · p. 6

C. Scalability Evaluation

The scalability evaluation increased offered GBR load while a Delay-Critical GBR flow retained its QoS configuration. GBR throughput saturated as radio resources filled, while Delay-Critical GBR throughput stayed near its configured MBR.

C. Scalability Evaluation

  • The test transmitted one GBR flow (5QI 1) and one Delay-Critical GBR flow (5QI 82), increasing offered GBR load from 40 to 140 Mbps.The Delay-Critical flow retained its original QoS configuration; each configuration ran for 360 s and was repeated ten times.Source: C. Scalability Evaluation · p. 6
  • Delay-Critical GBR throughput remained nearly constant and close to its configured MBR as competing GBR load increased.The authors report this as preserving higher-priority traffic.Source: C. Scalability Evaluation · p. 6
  • GBR throughput initially increased with offered load, then saturated when available radio resources were fully utilized.Source: C. Scalability Evaluation · p. 6

D. Discussion

Runtime logs and throughput measurements validate the hybrid mapping implementation. Compared with a single-DRB baseline, dynamically creating shared and dedicated DRBs reduces contention, preserves GBR throughput, lowers latency, and maintains Delay-Critical GBR performance near testbed capacity.

D. Discussion

  • The OAI implementation's runtime logs and throughput measurements validate realization of the hybrid QoS Flow-to-DRB mapping mechanism.Source: D. Discussion · p. 6
  • Compared with the baseline single-DRB implementation, dynamically creating shared and dedicated DRBs reduces contention and lowers latency.Source: D. Discussion · p. 6
  • The implementation preserves GBR throughput and maintains Delay-Critical GBR performance near the testbed's capacity limit.Source: D. Discussion · p. 6
  • The OAI implementation provides QoS differentiation for heterogeneous services within one PDU session while remaining compliant with the standardized 3GPP QoS framework.Source: D. Discussion · p. 6

VI. SUMMARY AND FUTURE WORKS

The paper presents a hybrid 5QI-based mapping mechanism, implemented on OpenAirInterface, for assigning flows to shared or dedicated DRBs within one PDU session. Experiments validate the mapping and report improved GBR throughput with isolation for Delay-Critical flows; future work targets runtime flow management through PFCP Session Modification.

VI. SUMMARY AND FUTURE WORKS

  • The mechanism dynamically assigns QoS flows to shared or dedicated DRBs based on standardized 5QI characteristics.It supports multiple QoS flows within a single PDU session.Source: §VI · p. 6
  • Implemented on OpenAirInterface, the framework improves radio resource utilization and experimentally validates the mapping.Source: §VI · p. 6
  • Experimental results demonstrate improved throughput for GBR traffic together with traffic isolation for Delay-Critical flows.Source: §VI · p. 6
  • The authors describe the framework as a practical and scalable solution for QoS-aware radio resource allocation in B5G networks.Source: §VI · p. 6
  • Future work will focus on dynamic QoS flow management through PFCP Session Modification to add and remove flows at runtime.Source: §VI · p. 6
Loading 2610.03209v1…