Radio resource management for uplink carrier aggregation in LTE-Advanced

Hua Wang,Klaus I Pedersen,Claudio Rosa

doi:10.1186/s13638-015-0329-y

Hua Wang, Klaus I Pedersen + Show 1 more

Open Access

https://doi.org/10.1186/s13638-015-0329-y

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Abstract

This paper investigates the uplink resource allocation problem in the context of Long-Term Evolution (LTE)-Advanced systems with carrier aggregation (CA) and dual-cluster scheduling. On one hand, these Rel’10 functionalities can increase the available transmission bandwidth and scheduling flexibility in uplink. On the other hand, they will introduce additional power back-off for the power amplifier in the user equipment (UE) with non-contiguous resource allocation. Taking into account that the uplink is inherently limited by the maximum transmission power of the UE, the assignment of uplink CA and/or dual cluster transmission for LTE-Advanced UEs has to be careful. A pathloss-threshold-based component carrier (CC) and cluster configuration algorithm is proposed to determine whether an LTE-Advanced UE should be configured with multiple CCs and/or dual cluster scheduling. An extended bandwidth-expansion-based packet scheduling algorithm is proposed for dual-cluster transmission, which tightly couples the bandwidth allocation and packet scheduling together to exploit the frequency domain diversity with low complexity. Simulation results show that with proper differentiation between power-limited and non-power-limited UEs, Rel’10 CA with dual-cluster scheduling can maintain similar coverage performance as in Rel'8 case while achieving substantial gains in median and peak user throughputs. Moreover, the proposed CC assignment algorithm achieves higher user throughput as compared to blindly assigning all UEs on all available CCs.

Highlights

Carrier aggregation (CA) is one of the key features for Long-Term Evolution (LTE)-Advanced to support higher transmission bandwidth up to 100 MHz, enabling peak date rates requirements of up to 1 Gbps in downlink and 500 Mbps in uplink to be satisfied
For layer 3 component carrier (CC) configuration, we have derived a pathloss threshold that separates the user equipment (UE) into two categories: power-limited and non-power-limited UEs, and assign only one CC with single-cluster transmission to power-limited LTE-A UEs but assign multiple CCs with dual-cluster transmission to non-power-limited LTE-Advanced UEs
For layer 2 packet scheduling, we have proposed an extended bandwidth expansion resource allocation algorithm with joint proportional fair (PF)

Summary

Introduction

Carrier aggregation (CA) is one of the key features for Long-Term Evolution (LTE)-Advanced to support higher transmission bandwidth up to 100 MHz, enabling peak date rates requirements of up to 1 Gbps in downlink and 500 Mbps in uplink to be satisfied. Configuring LTE-Advanced users with multiple CCs and/or dual-cluster transmission in principle only makes sense if its total transmission power does not exceed the maximum UE power capability Otherwise, they do not have sufficient power to exploit the increased transmission bandwidth and scheduling flexibility. LTE-Advanced users whose pathloss satisfies Equation 7 are considered to be non-power-limited and can be assigned on multiple CCs with dual-cluster transmission. By separating the power-limited and nonpower-limited LTE-Advanced users, cell-edge LTEAdvanced users will not experience any performance loss with non-contiguous resource allocation, while nonpower-limited LTE-Advanced users can benefit from increased transmission bandwidth and scheduling flexibility with CA and multi-cluster transmission.

Simulation results and analysis

Findings

Conclusions