This paper presents an experimental and analytical investigation of ultra-wideband (3-8 GHz) body-to-body (B-to-B) channel characterization. The channel parameters obtained are compared with off-body (off-B) and no-body (no-B) links. Measurements have been carried out considering different body positions and orientation of the Tx-Rx pair. The type of channel link and position of the wearable antenna lead to significant changes in the radio link channel. Path loss (PL) computed shows the increase in magnitude for non line of sight (NLOS) in comparison to line of sight (LOS), though the variation over a distance of 5 m is more significant for LOS (10 dB) than NLOS links (4-5 dB). For total NLOS links, B-to-B channels have slightly higher PL and delay spread parameters in comparison to off-B channel. The B-to-B LOS channels have least PL (44-56 dB), rms delay spread (0.5-4 ns), and multipath components (3-20) which can be attributed to the directional radiation pattern due to the presence of the human body for both Tx and Rx nodes. For back-to-back antenna orientation of the B-to-B channel, maximum signal strength degradation and multipath are observed. It can be concluded that for certain links, the B-to-B channel shows a significant change in channel behavior in comparison to off-B/no-B scenario.