  The application of LTE technology has evolved from infrastructure-based
deployments in licensed bands to new use cases covering ad hoc,
device-to-device communications and unlicensed band operation. Vehicular
communication is an emerging field of particular interest for LTE, covering in
our understanding both automotive (cars) as well as unmanned aerial vehicles.
Existing commercial equipment is designed for infrastructure making it
unsuitable for vehicular applications requiring low weight and unlicensed band
support (e.g. 5.9 GHz ITS-band). In this work, we present tinyLTE, a system
design which provides fully autonomous, multi-purpose and ultra-compact LTE
cells by utilizing existing open source eNB and EPC implementations. Due to its
small form factor and low weight, the tinyLTE system enables mobile deployment
on board of cars and drones as well as smooth integration with existing
roadside infrastructure. Additionally, the standalone design allows for systems
to be chained in a multi-hop configuration. The paper describes the lean and
low-cost design concept and implementation followed by a performance evaluation
for single and two-hop configurations at 5.9 GHz. The results from both lab and
field experiments validate the feasibility of the tinyLTE approach and
demonstrate its potential to even support real-time vehicular applications
(e.g. with a lowest average end-to-end latency of around 7 ms in the lab
experiment).
