For the most part, it seems like Odysseus—the main character of Homer's Odyssey—is the speaker of "Canto I." The way he keeps using "we" at the beginning of the poem definitely suggests that the speaker is at least among Odysseus' crew. The later story about traveling to the underworld and the fact that the speaker is surprised that his friend Elpenor is dead definitely identifies it as Odysseus… or does it?
When you think about it, Pound's use of "we" in the opening lines of the poem might actually be including you, the reader, as a member of Odysseus' crew. Pound wants you to feel as though you are one of the crew members traveling around with Odysseus on his journey home. From Pound's perspective, we all need to face the challenges of life together, and this means working together to find a home for ourselves and to know the stories of our past (like Homer's Odyssey).
Toward the very end of "Canto I" (line 68), Pound seems to interrupt Odysseus' speaking and starts talking about the actual version of The Odyssey he's been working from, a translation from some dude named Andreas Divus in 1538. So here, you're looking at a real "meta" moment. You think you've been listening to Odysseus the whole time, but here you realize (by design) that you've actually been listening to Pound using Odysseus like a sort of hand puppet.
So why pull back the curtain in this way? As far as our speaker is concerned, Pound seems to be reminding us to see Odysseus in this poem for who he really is. Sure, he's our speaker, but this poem is not strictly his story. Pound's isn't retelling The Odyssey just because he thinks it's a great story. He's got a point to using Odysseus as his speaker. He wants us modern readers to draw our own connections to this ancient hero's dilemmas.