Performance enhancement via efficient buffer and cache utilization in Uplink Control Path for LTE

Abstract

Physical Uplink Control Channel (PUCCH) is a transmission channel used to transport acknowledgment responses and retransmission requests (Hybrid Automatic Repeat Request (HARQ ACK/NACK)) for Downlink (DL) data packets, send service scheduling requests (SR), transfer channel quality information (CQI) and Multiple Input Multiple Output (MIMO) feedback (such as Rank Indicator (RI) or Precoding Matrix Indicator (PMI) from one or more User Equipment (UE) that can transmit on the control channel to an Evolved Node-Base Station (eNB). In this paper we analyze an existing PUCCH design, which is a part of LTE Uplink Processing Chain and propose methods to optimize the performance of the Uplink Control Path with no incremental change in underlying hardware resources. The proposed design decreases the processor resource consumption by the PUCCH decoder by half (best case) and simplifies LTE Layer 1 Scheduler Design, thereby allowing the system to achieve higher throughput. The results are compared via black box testing over configuration supported by the system. The proposed improvements can be leveraged in other parts of LTE Uplink and Downlink Processing Chain for performance gains.