Infrastructureless 5G

A system for operating an ad hoc communication network under suboptimal commercial global navigation satellite system (GNSS) conditions and a loss of a base station communication link comprising:

• a base station;
• a first user device;
• wherein the base station and the first user device are configured to communicate via a first signal;
• and
• a second user device configured to communicate with the base station via a second signal;
• wherein the base station is configured to operate as a relay between the first user device and the second user device;
• wherein the first user device and the second user device are configured to communicate directly without the use of the base station;
• wherein the first user device and the second user device communicate via a third signal;
• the first user device comprising:
• a transceiver configured to communicate with the second user device;
• a memory configured to perform an instruction;
• a processor configured to execute the instruction stored by the memory, wherein the instruction enables the processor to:
• configure the first user device to operate in in-band mode, wherein cellular communication and device-to-device (D2D) communication are supported in a same band;
• wherein the third signal is configured to use the same frequency of the first signal and the second signal;
• configure the first user device to operate in overlay mode, wherein communication resources are shared between network-controlled resources and D2D resources;
• configure the D2D resources with a base station precedent to the loss of the base station communication link;
• enable the first user device to operate in frequency hopping mode;
• wherein the first user device and the second user device are configured to communicate by switching the third signal among several frequency channels;
• enable physical sidelink control channel synchronization for the first user device, wherein the first user device is configured to provide short-range timing to the second user device via the physical sidelink control channel synchronization;
• and
• disable the physical sidelink control channel synchronization within the first user device.