Systems/methods of wireless communications advancements that conserve power and bandwidth

A first device that is configured to perform operations comprising:

• receiving configuration information, from a second device, relating to a plurality of transmit modes any two of which differ from one another in at least bandwidth, frequencies, subcarriers, a power level, an antenna configuration and/or a physical layer of an air interface;
• and
• establishing the plurality of transmit modes and storing configuration parameters at the first device for the plurality of transmit modes;
• then
• communicating with the second device using a first transmit mode of the plurality of transmit modes that have been established;
• and
• selecting and using a second transmit mode of the plurality of transmit modes that have been established responsive to an index parameter received from the second device that relates to configuration parameters stored at the first device for the second transmit mode and/or selecting and using the second transmit mode of the plurality of transmit modes that have been established responsive to a parameter associated with data that is to be transmitted;
• wherein data transmission via the second transmit mode differs from data transmission via the first transmit mode in bandwidth, frequencies, subcarriers, physical layer of air interface used and power usage;
• and
• wherein the parameter associated with data that is to be transmitted comprises a value of data, a quality-of-service, a size of data, a velocity, an interference level, a bit-error-rate, a data rate, a time-of-day, a security/privacy concern, a location of the second device and/or a distance between the first device and the second device.