This use case describes a basic scenario for ProSe Discovery that can be used for any application. A social networking application is used as an example to illustrate this use case.

An operator offers a service which makes use of the ProSe feature, in which:

• A ProSe-enabled UE of a given user is able to discover and be discoverable by the ProSe-enabled UEs of his/her friends;
• A social networking application is enabled to use this ProSe feature.

Mary, Peter and John use a given social networking application. In the context of this application, the following relationships are established:

• Mary and John are friends;
• John and Peter are friends;
• Mary and Peter are not friends;
• There might be hundreds of other ProSe-enabled UEs in the vicinity of Mary using the same or other applications.

In addition, the following assumptions are made:

• Mary, Peter and John use ProSe-enabled UEs;
• Mary, Peter and John are subscribed to the same cellular operator;
• Mary, Peter and John are currently residing on their HPLMN;
• Mary, Peter and John are subscribed to an operator service that allows them to use ProSe;
• Mary has given permission to John to discover her and vice versa;
• John has given permission to Peter to discover him and vice versa.

The social networking application used by Mary, Peter and John is enabled by the operator to benefit from ProSe.

Mary decides to look for a friend via her application, and so do John and Peter. Thus (e.g. following interaction with her application), as Mary's UE comes into proximity of John's and Peter's UEs, the user experience is such that, without any further user interaction with the device:

• Mary's UE detects (for example using direct radio signals or via the operator's network) that John's UE is in its proximity;
• John's UE detects that Mary's UE is in its proximity;
• Mary's social networking application learns that John is in or out of her proximity;
• John's social networking application learns that Mary and Peter are in or out of his proximity;
• Mary's UE does not detect that Peter's UE is in its proximity;
• Peter's UE does not detect that Mary's UE is in its proximity;
• Mary's social networking application does not detect that Peter is in or out of her proximity;
• Peter's social networking application does not detect that Mary is in or out of his proximity.

As the social network application of Mary detects that John is in her proximity, Mary may decide to transfer data to John via the social networking application. ProSe Discovery is achievable without any location information.

None

[PR.1] [PR.98] [PR.2] [PR.3]

• a ProSe-enabled UE to discover other UEs in its proximity but not be discoverable;
• a ProSe-enabled UE to be discoverable by other UEs but not be able to discover other UEs in its proximity;
• a ProSe-enabled UE to discover other UEs in its proximity and be discoverable by other UEs;
• a ProSe-enabled UE to disable the ability to be discoverable by other UEs and to disable the ability to discover other UEs;
• a ProSe-enabled UE to revoke being discoverable by a ProSe-enabled UE (i.e. be discoverable by a UE at one time, and then not discoverable by the same UE at another time);
• a ProSe-enabled UE to discover ProSe-enabled UEs of interest, where interest is defined in a ProSe-enabled application per user, group of users, or category of users;
• a ProSe-enabled UE to restrict discoverability to ProSe-enabled UEs of interest, where interest is defined in a ProSe-enabled application per user, group of users, or category of users.

[PR.97] [PR.4] [PR.5] [PR.6] [PR.xy] [PR.7] [PR.8] [PR.9] [PR.10] [PR.11] [PR.12] [PR.13] [PR.14] [PR.15] [PR.16]

• The ability for a UE to be discoverable, including based on the range class;
• The ability to discover other UEs, including based on the range class;
• The event of discovering a UE, including based on the range class.

This use case describes a case in which UEs discover other UEs without permission by the discoverable UEs.

Mary uses a given application. In the context of this application, the following assumptions are made:

• Mary, Store A and Restaurants A, B and C use ProSe-enabled UEs;
• Mary and the owners of the store and restaurant UEs are subscribed to an operator service that allows them to use ProSe;
• There might be hundreds of other stores/restaurants with ProSe-enabled UEs in the vicinity of Mary;
• The operator has enabled the application to access this ProSe feature.

As Mary walks into the neighbourhood where Store A is located, Mary is notified of the proximity of Store A. Mary then decides to look for a restaurant, and thus (e.g., following interaction with her application), Mary is notified of the proximity of Restaurant A. Mary is not notified of the proximity of other establishments which are not determined to be of interest according to the application she is using. After she starts walking towards Restaurant B, Mary is notified of the proximity of Restaurant B, and also of Restaurant C.

Mary's application is aware of Store A, Restaurants A, B and C.

[PR.17]

• Served by the same PLMN, including when roaming;
• Served by different PLMNs, including when roaming.

This use case describes discovery between UEs camped on different PLMNs.

The same pre-conditions as in clause 5.1.1 apply except that

• Mary is a subscriber to operator A and camps on operator A's network;
• John is a subscriber to operator B and camps on operator B's network.

As John moves towards Mary, the user experience is such that, without any further user interaction with the UE:

• Mary is notified that John is in her proximity;
• John is notified that Mary is in his proximity.

John and Mary are aware of their proximity to each other.

[PR.18] [PR.19] [PR.20]

This use case describes discovery between UEs in different PLMNs under roaming conditions.

The same pre-conditions as in clause 5.1.1 apply except that

• Mary is a subscriber to operator A and camps on operator A's network (i.e. her HPLMN);
• John is a subscriber to operator C in a different country and currently roams in operator B's network, which is located in the same country as operator A's network.

As John moves towards Mary, the user experience is such that, without any further user interaction with the UE:

• Mary is notified that John is in her proximity;
• John is notified that Mary is in his proximity.

John and Mary are aware of their proximity to each other.

[PR.21] [PR.22] [PR.23] [PR.24] [PR.25]

• The ability to be discoverable;
• The ability to discover;
• The event of discovering a UE.

In this use case, the 3GPP network provides ProSe Discovery for ProSe-enabled UEs.

• Mary and Peter use ProSe-enabled UEs, subscribe to the same MNO, and currently reside on the HPLMN.
• The MNO network supports ProSe Discovery and Communication.

• Mary uses an application on her UE to connect with Peter, causing her UE to request ProSe Discovery from the MNO network.
• The MNO network verifies that Mary's UE has permission to discover Peter's UE and is in proximity of Peter's UE.
• The network informs Mary's and Peter's UEs that they are in proximity.

Mary's and Peter's UEs have discovered each other.

[PR.26] [PR.91]

In this use case UEs communicate initially via an infrastructure path, then via a ProSe Communication path and finally return to an infrastructure path.

An operator offers a service which makes use of the ProSe feature, in which:

• The operator is able to establish a new user traffic session using E-UTRA ProSe communication;
• The operator is able to switch user traffic from an infrastructure communication path to an E-UTRA ProSe communication path.

In addition, the following assumptions are made:

• Mary and Peter use ProSe-enabled UEs;
• Mary and Peter are subscribed to the same cellular operator;
• Mary and Peter are currently residing on their HPLMN;
• Mary and Peter are subscribed to an operator service that allows them to use ProSe;
• Mary and Peter have performed ProSe discovery and initiation of ProSe communications.

Mary and Peter are engaged in a data session (including one or more flows) that is being routed over the MNO's core network infrastructure. As Peter moves within proximity of Mary, one or more flows of the data session is switched to an E-UTRA ProSe communication path. At some point later, the data session is switched back to the infrastructure path. The user experience is such that the switching of the data path is not perceived by the users. The user experience of the ongoing user traffic sessions is such that any un-switched data flows are not negatively impacted by the switching of other data flows.

None

[PR.99] [PR.27]

• Served by the same PLMN, including when roaming;
• Served by different PLMNs, including when roaming.

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• System-specific conditions: backhaul link, supporting links or EPC performance;
• Cell-specific conditions: for example cell loading;
• ProSe Communication and infrastructure path conditions: communication range, channel conditions and achievable QoS;
• Service-type conditions: APN, service discriminator.

[PR.95]