  Dimensional regularization is applied to the computation of the gravitational
wave field generated by compact binaries at the third post-Newtonian (3PN)
approximation. We generalize the wave generation formalism from isolated
post-Newtonian matter systems to d spatial dimensions, and apply it to point
masses (without spins), modelled by delta-function singularities. We find that
the quadrupole moment of point-particle binaries in harmonic coordinates
contains a pole when epsilon = d-3 -> 0 at the 3PN order. It is proved that the
pole can be renormalized away by means of the same shifts of the particle
world-lines as in our recent derivation of the 3PN equations of motion. The
resulting renormalized (finite when epsilon -> 0) quadrupole moment leads to
unique values for the ambiguity parameters xi, kappa and zeta, which were
introduced in previous computations using Hadamard's regularization. Several
checks of these values are presented. These results complete the derivation of
the gravitational waves emitted by inspiralling compact binaries up to the
3.5PN level of accuracy which is needed for detection and analysis of the
signals in the gravitational-wave antennas LIGO/VIRGO and LISA.
