The definition of "Open RAN Standard" may be found in Section 1.19 of the Open RAN Patent Portfolio License. It is defined as the LTE and 5G RAN functionality that is implemented in a radio unit that has the same Low Physical Layer functionality as a microcell or picocell specified by the O-RAN Alliance (see here for these specifications). This functionality is also defined in 3GPP TR 38.801 as the 7-2 split option and also includes the precoding function (the O-RAN Alliance calls this option the 7-2x split). These functions are covered, for example, by 3GPP Technical Specifications 38.104, 38.106, 38.113, 38.114, 36.104, 36.106, 36.111, 36.112, and 36.113 and various sections of Technical Specifications 38.201, 38, 211, 38.212, 38.213, 36.211, and 36.213 See here and here for a list of these specifications.

No, the Open RAN Standard does not include the fronthaul connection, which in O-RAN specified radio units is the Common Public Radio Interface (for LTE it's CPRI and for 5G it's eCPRI). CPRI arose in 2003 from the collaboration among Ericsson, Huawei, Siemens, and NEC. Nokia joined the work later. These entities offer the royalty free non-assert (found here) with respect to their patents essential to the CPRI and eCPRI interfaces.

No, a Licensee's coverage includes all "Open RAN Essential Patents" to which a Licensor and its Affiliates have the right to grant a worldwide, nonexclusive, non-transferable license or sublicense presently or in the future. As a result, no patent list will be attached to the Open RAN Patent Portfolio License or made available to Licensees.

The purpose of the License is to offer a convenient licensing alternative to everyone on the same terms and to include as much essential intellectual property as possible for their convenience. Participation in the License is voluntary on the part of essential patent holders, however. No assurance is or can be made that the Open RAN Patent Portfolio License includes all Open RAN Essential patent holders.

To be eligible to become a Licensor, a patent holder must have one patent determined to be an Open RAN Essential Patent to the Open RAN Standard by an independent patent expert hired and paid for by Alium.

This is to be distinguished from "Open RAN Statistically Essential Patents" which are used to define a patent counting unit solely for the purposes of allocating and distributing royalty revenue to Licensors through the Alium pool using the Open RAN IP Analytics. For the methodology by which the Open RAN IP Analytics were created and continue to be developed, see here.