You haven't provide some CLI output, so I'll assume that it's the following line you're asking about...
Peer LDP Ident: 10.2.0.2:0; Local LDP Ident 10.1.0.1:0
The peer Identity comes from the LDP TCP session that estblished bewteen two routers over a connected link, they find eachother using UDP port 646, and the TCP session is estblished using the TCP port 646...
If you specify the command 'mpls ldp router-id loopback X' this address will be used as the source address in the TCP session, if you use another address for example a loopback address you need IGP routing to transport the source addresses between the routers, else the LDP neighbours won't come up.
/Anders.