ARQ Concept for the UMTS Long-Term Evolution

Work is ongoing in 3GPP to significantly extend the performance of UMTS in the work item long term evolution (LTE). LTE contains a new system architecture with fewer infrastructure nodes and it has been decided to terminate the ARQ functionality in the evolved node B. This paper describes the requirements that exists for an LTE ARQ concept and outlines a solution that fulfills these requirements in the new LTE architecture. The solution builds on two layered ARQ feedback mechanisms that provide sufficient reliability with a low resource cost for the feedback The paper contains thorough stepwise argumentation how we arrived at the proposed ARQ concept.