Detection and Mitigation of Uplink Control Channel Jamming in LTE

In 3GPP LTE, the physical layer is divided into data and signaling, where the signaling (or control information) enables efficient data exchange/resource scheduling. The LTE uplink contains a physical channel known as the Physical Uplink Control Channel (PUCCH), which carries uplink control information such as message acknowledgements, scheduling requests, and channel status information from user equipment (UE) to LTE base stations (eNodeB). The PUCCH is located on the edges of the system bandwidth in a static location. The static allocation of the PUCCH presents a dilemma: an adversary can disrupt the uplink channel with minimal effort and only needs to know the PUCCH´s spectrum allocation. In this paper we (i) take a closer look at the purpose and specification of the PUCCH, (ii) we propose various strategies to be used for the detection of interference specifically on the PUCCH, and (iii) we outline strategies for mitigating ´protocol-aware´ interference on the PUCCH. Some of the mitigation strategies, such as control information duplication, can be implemented with minimal changes to LTE eNodeBs and UEs, while other countermeasures require augmentations to both eNodeB and UE hardware or software.