I need to send .doc file from my Nexus 5 phone to a Windows 8 desktop (with an ACR122U-A9 NFC reader connected to it). Similar projects I have found use LLCP/SNEP protocol (such as Android Beam that can be found in this link: https://code.google.com/p/java-android-beam-api/). Since there is a new feature of host-based card emulation, I would like to know if I can use HCE instead of LLCP/SNEP to establish communication between Android and the ACR122U?
Yes you can use HCE to establish a connection between your phone and the ACR122U but that's not the P2P you are talking about. P2P is when both devices use a P2P protocol to exchange information. With HCE emulates a tag on your Android device which you can read with your ACR122U. Once you establish a connection it's possible to exchange bidirectional communication but you should use the ISO-DEP protocol instead of a P2P protocol. Read the information of the link below. It will give you more general information about HCE. https://developer.android.com/guide/topics/connectivity/nfc/hce.html