  A simple protocol is described for transferring spatial direction from Alice
to Bob (two spatially separated observers) up to inversion. The two observers
are assumed to share quantum singlet states and classical communication. The
protocol assumes that Alice and Bob have complete free will (measurement
independence) and is based on maximizing the Shannon mutual information between
Alice and Bob's measurement outcomes. Repeated use of this protocol for each
spatial axis of Alice allows transfer of a complete 3-dimensional reference
frame, up to inversion of each of the axes. The technological complexity of
this protocol is similar to that needed for BB84 quantum key distribution, and
hence is much simpler to implement than recently proposed schemes for
transmission of reference frames. A second protocol based on a Bayesian
formalism is also presented.
