ProSe Discovery identifies that ProSe-enabled UEs are in proximity of each other, using E-UTRA (with or without E-UTRAN) or EPC when permission, authorisation and proximity criteria are fulfilled. The proximity criteria can be configured by the operator.
The use of ProSe Discovery must be authorised by the operator, and the authorisation can be on a "per UE" basis, or a "per UE per application" basis. An authorised application can interact with the ProSe Discovery feature to request the use of certain ProSe Discovery preferences.
The network controls the use of E-UTRAN resources used for ProSe Discovery for a ProSe-enabled UE served by E-UTRAN.
ProSe Discovery can be used as a standalone process (i.e. it is not necessarily followed by ProSe Communication) or as an enabler for other services.
ProSe Communication enables establishment of new communication paths between two or more ProSe-enabled UEs that are in Communication Range. The ProSe Communication path could use E-UTRA or WLAN. In the case of WLAN, only ProSe-assisted WLAN direct communication (i.e. when ProSe assists with connection establishment management and service continuity) is considered part of ProSe Communication.
The network controls the use of E-UTRAN resources used for ProSe Communication for a ProSe-enabled UE served by E-UTRAN. The use of ProSe Communication must be authorised by the operator.
According to operator policy a UE's communication path can be switched between an EPC Path and a ProSe Communication path and a UE can also have concurrent EPC and ProSe Communication paths.
ProSe Communication is also facilitated by the use of an Evolved ProSe UE-to-Network Relay, which acts as a relay between E-UTRAN and Evolved ProSe Remote UEs. The use of this relay function is controlled by the network.
For Public Safety specific usage:
ProSe Communication can start without the use of ProSe Discovery if the Public Safety ProSe-enabled UEs are in Communication Range.
Public Safety ProSe-enabled UEs must be able to establish the communication path directly between Public Safety ProSe-enabled UEs, regardless of whether the Public Safety ProSe-enabled UE is served by E-UTRAN, as well as being able to participate in ProSe Group Communication or ProSe Broadcast Communication between two or more Public Safety ProSe-enabled UEs which are in proximity. Any of the involved Public Safety ProSe-enabled UEs need to have authorisation from the operator.
In addition, ProSe Communication can also take place over a ProSe UE-to-UE Relay, a form of relay in which a Public Safety ProSe-enabled UE acts as a ProSe E-UTRA Communication relay between two other Public Safety ProSe-enabled UEs.
Based on operator policy and user choice, the proximity of two ProSe-enabled UEs shall be determinable; for example, using direct radio signals or via the operator network.
Subject to user and operator settings, the 3GPP system shall be able to support the usage of WLAN direct discovery.
In the case the ProSe-enabled UE supports WLAN direct discovery, the 3GPP network shall be able to configure applications in the UE to use E-UTRA direct discovery or WLAN direct discovery or both for discovering other ProSe-enabled UEs.
ProSe Discovery shall be able to determine whether or not other ProSe-enabled UEs are of interest to a discovering ProSe-enabled UE. A ProSe-enabled UE is of interest to a discovering ProSe-enabled UE if its proximity needs to be known by one or more authorised applications.
Subject to user and operator settings, a ProSe-enabled UE shall be able to be discoverable only by other ProSe-enabled UEs in proximity that are explicitly permitted by the discoverable ProSe-enabled UE.
Subject to user and operator settings, a ProSe-enabled UE shall be able to be discoverable by all other ProSe-enabled UEs in proximity without explicit permission. The ProSe-enabled UEs can be served by the same or different PLMN, including when roaming.
All requirements for ProSe Discovery also apply when one or both of the ProSe-enabled UEs involved in ProSe Discovery are roaming in a VPLMN.
Operator policy disabling or limiting individual ProSe features shall override any user choice.
The following requirements apply to the case where ProSe-enabled UEs use E-UTRA to determine proximity of other ProSe-enabled UEs:
The operator shall be able to dynamically control the proximity criteria for ProSe Discovery. Examples of the criteria include radio range and geographic range.
ProSe Discovery shall support a minimum of three range classes - for example short, medium and maximum range.
The operator shall be able to authorise per subscription the maximum range class ProSe Discovery is allowed to use.
The ProSe Discovery process shall enable authorised applications to request and to use a certain range class when discovering other ProSe-enabled UEs.
The ProSe Discovery process shall enable authorised applications to request and to use a certain range class when the ProSe-enabled UE is being discovered by other ProSe-enabled UEs.
The operator shall be able to dynamically control the proximity criteria for any ProSe E-UTRA Communication (including ProSe E-UTRA Communication between two ProSe-enabled UEs, ProSe Group Communication and ProSe Broadcast Communication). Examples of the criteria include: Communication Range, channel conditions, achievable QoS.
The impact of ProSe Discovery and ProSe Communication on E-UTRA radio usage, network usage and battery consumption should be minimized. This requirement applies to any ProSe E-UTRA Communication between two ProSe-enabled UEs, ProSe Group Communication, ProSe Broadcast Communication, and ProSe-assisted WLAN direct communication.
ProSe shall support the simultaneous operation of a large number of applications on a ProSe-enabled UE, ensuring that the 3GPP system provides ProSe Discovery proximity information only to applications that were authorised by the 3GPP operator.
An application on a ProSe-enabled UE shall be able to use ProSe Discovery to request EPC ProSe to determine the proximity of another ProSe-enabled UE; EPC ProSe shall be able to determine proximity of two ProSe-enabled UEs and inform the requesting application of their proximity.
The operator shall be able to enable or disable the ProSe Discovery feature in its network.
The system shall be capable of monitoring communication characteristics (e.g. channel condition, QoS of the path, volume of traffic etc.) on the ProSe E-UTRA Communication path, regardless of whether there is an existing data session on the EPS path. This requirement applies to any ProSe E-UTRA Communication between two ProSe-enabled UEs, ProSe Group Communication and ProSe Broadcast Communication. The monitored communication characteristics on the ProSe E-UTRA Communication path (e.g. channel condition, QoS of the path, volume of traffic etc.) may be different for ProSe E-UTRA Communication between two ProSe-enabled UEs, ProSe Group Communication and ProSe Broadcast Communication.
The establishment of a user traffic session on the ProSe E-UTRA Communication path and the switching of user traffic between a ProSe E-UTRA Communication path and an EPC Path are under control of the network. This requirement applies to any ProSe E-UTRA Communication between two ProSe-enabled UEs, ProSe Group Communication and ProSe Broadcast Communication.
The Radio Access Network shall control the radio resources associated with the ProSe E-UTRA Communication path. This requirement applies to any ProSe E-UTRA Communication between two ProSe-enabled UEs, ProSe Group Communication and ProSe Broadcast Communication.
The ProSe mechanism shall enable the operator to change the communication path of a user traffic session to a ProSe Communication path or EPC Path without negatively affecting the QoS of the session. This requirement is not applicable to ProSe Group Communication and ProSe Broadcast Communication.
The ProSe mechanism shall enable the operator to change the communication path of a user traffic session of a ProSe-enabled UE to a ProSe Communication path or EPC Path without negatively affecting the communication paths (including ProSe Communication paths) of other ongoing user traffic sessions of this or other ProSe-enabled UEs. This requirement is not applicable to ProSe Group Communication and ProSe Broadcast Communication.
The ProSe mechanism shall enable the operator to change the communication path of a user traffic session to a ProSe Communication path or EPC Path based upon the QoS requirements of the session and the QoS requirements of other ongoing sessions of this or other ProSe-enabled UEs. This requirement is not applicable to ProSe Group Communication and ProSe Broadcast Communication.
The system shall be capable of selecting the most appropriate communications path (ProSe Communication path or EPC Path), according to operator preferences. This requirement is not applicable to ProSe Group Communication and ProSe Broadcast Communication. The criteria for evaluation may include the following, although not restricted to:
System-specific conditions: backhaul link, supporting links or EPC performance;
Cell-specific conditions: for example cell loading;
ProSe and EPC Path conditions: Communication Range, channel conditions and achievable QoS;
Service-type conditions: APN, service discriminator.
Subject to operator policy and user consent, the system shall be capable of establishing a new user traffic session with a ProSe E-UTRA Communication path, and maintaining both of the ProSe E-UTRA Communication path and the existing EPC Path, when the UEs are determined to be in Communication Range allowing ProSe E-UTRA Communication. This requirement applies to any ProSe E-UTRA Communication between two ProSe-enabled UEs, ProSe Group Communication and ProSe Broadcast Communication. The UEs can be:
Served by the same PLMN, including when roaming; or
Served by different PLMNs, including when roaming.
The 3GPP system shall be capable of moving a user traffic session from the EPC Path to a ProSe E-UTRA Communication path, when the ProSe-enabled UEs are determined to be in Communication Range allowing ProSe E-UTRA Communication. This requirement applies to any ProSe E-UTRA Communication between two ProSe-enabled UEs, ProSe Group Communication and ProSe Broadcast Communication.
The 3GPP system shall be capable of moving a user traffic session from a ProSe E-UTRA Communication path to an EPC Path. At a minimum, this functionality shall support the case when the ProSe E-UTRA Communication path is no longer feasible. This requirement applies to any ProSe E-UTRA Communication between two ProSe-enabled UEs, ProSe Group Communication and ProSe Broadcast Communication.
When switching user traffic sessions between the ProSe E-UTRA Communication and EPC Paths triggered by the network, disruption to the user shall be minimized. This requirement is not applicable to ProSe Group Communication and ProSe Broadcast Communication.
When switching user traffic sessions between the ProSe E-UTRA Communication and EPC Paths triggered by the ProSe-enabled UE, disruption to the user shall be minimized. This requirement is not applicable to ProSe Group Communication and ProSe Broadcast Communication.
The HPLMN operator shall be able to authorize the ability of a ProSe-enabled UE to use ProSe Communication, separately for the HPLMN and for roaming in VPLMNs. This requirement applies to any ProSe E-UTRA Communication between two ProSe-enabled UEs, ProSe Group Communication, ProSe Broadcast Communication and ProSe-assisted WLAN direct communication.
The HPLMN operator shall be able to authorize the ability of a ProSe-enabled UE to use ProSe Communication to communicate with ProSe-enabled UEs served by a different PLMN. This requirement applies to any ProSe E-UTRA Communication between two ProSe-enabled UEs, ProSe Group Communication, ProSe Broadcast Communication and ProSe-assisted WLAN direct communication.
The VPLMN operator shall be able to turn on or off the ability for all the inbound roamers from a specific PLMN to use ProSe Communication. This requirement applies to any ProSe E-UTRA Communication between two ProSe-enabled UEs, ProSe Group Communication, ProSe Broadcast Communication and ProSe-assisted WLAN direct communication.
ProSe proximity information shall be suitable for integration with the Location and Presence information used by the network to offer its services.
ProSe shall be able to accommodate potentially large numbers of concurrently participating ProSe-enabled UEs.
ProSe Discovery and ProSe Communication shall be available to ProSe-enabled UEs that are registered to a PLMN and are served by an E-UTRAN of said PLMN even if potentially served by different eNBs. Whether or not UEs are served by the same eNB, E-UTRAN resources involved in ProSe will be under real time 3GPP network control.
The network shall be able to collect Discovery information from a ProSe-enabled UE regarding which ProSe-enabled UEs are discovered to be in its proximity. Restrictions due to regulation on data collection apply.
ProSe shall:
Allow a ProSe-enabled UE to selectively discover ProSe-enabled UEs of interest;
Ensure that 3GPP UE/subscriber identifiers are not disclosed to unauthorised parties when ProSe is used;
Allow both granting and revocation of discovery permissions;
Enable applications to individually request the setting of discovery parameters, such as discovery range class.
A minimum set of ProSe Discovery and ProSe Communication capabilities for applications may be defined and present on ProSe-enabled UEs, providing ProSe features for applications.
The operator network shall be able to continuously control the use of E-UTRAN resources for ProSe Discovery and ProSe E-UTRA Communication between UEs, as long as these UEs are served by E-UTRAN and using operator's spectrum. This requirement applies to any ProSe E-UTRA Communication between two ProSe-enabled UEs, ProSe Group Communication and ProSe Broadcast Communication.
Potential negative impact of ProSe on the E-UTRAN services should be minimized. This requirement applies to any ProSe E-UTRA Communication between two ProSe-enabled UEs, ProSe Group Communication, ProSe Broadcast Communication, and ProSe-assisted WLAN direct communication.
Subject to operator policies MOCN networks shall support establishing ProSe Communication between ProSe-enabled UEs camping on the same radio access network but served by different MOCN PLMNs. This requirement applies to any ProSe E-UTRA Communication between two ProSe-enabled UEs, ProSe Group Communication, ProSe Broadcast Communication and ProSe-assisted WLAN direct communication.
A Public Safety ProSe-enabled UE with ProSe Discovery enabled for discovery of other public safety UEs shall be able to discover other discoverable public safety UEs, without network interaction if allowed by the operator, even when served by E-UTRAN whether or not ProSe E-UTRA Communication is used (including whether or not ProSe Group Communication or ProSe Broadcast Communication are used).
A user of a Public Safety ProSe-enabled UE shall be able to activate or deactivate the UE's ProSe Discovery feature while served by E-UTRAN, if allowed by the operator whether or not ProSe E-UTRA Communication is used (including whether or not ProSe Group Communication or ProSe Broadcast Communication are used).
ProSe shall not be available to ProSe-enabled UEs not served by E-UTRAN, except in the following cases:
Public Safety ProSe-enabled UEs can use ProSe when operating on public safety spectrum even when not served by E-UTRAN. In this case, at least a one-time pre-authorization to use ProSe is needed.
A Public Safety ProSe-enabled UE with ProSe Discovery enabled shall be able to discover other discoverable Public Safety ProSe-enabled UEs when some or all of the Public Safety ProSe-enabled UEs involved in ProSe Discovery are not served by E-UTRAN, whether or not ProSe E-UTRA Communication is used (including whether or not ProSe Group Communication or ProSe Broadcast Communication are used).
A Public Safety ProSe-enabled UE shall be capable of determining autonomously whether or not a discovered ProSe-enabled UE is a public safety UE.
The configuration of a Public Safety ProSe-enabled UE that allows the Public Safety ProSe-enabled UE to discover other discoverable Public Safety ProSe-enabled UEs shall be independent from its configuration to allow or not to allow other Public Safety ProSe-enabled UEs to discover it.
Public Safety ProSe-enabled UEs whether they are served by E-UTRAN or not, shall be capable of establishing a secure ProSe E-UTRA Communication on a ProSe E-UTRA Communication path and exchange user traffic on public safety spectrum, assuming they are in Communication Range, are authenticated and authorised. This requirement applies to ProSe E-UTRA Communication between two Public Safety ProSe-enabled UEs, ProSe Group Communication and ProSe Broadcast Communication.
ProSe-enabled UEs shall not be able to use ProSe Discovery and/or Communication services when in Limited Service state, except for Public Safety ProSe-enabled UEs which shall be treated as out-of-coverage under the following circumstances:
It cannot find a suitable cell of the selected PLMN
It receives a "PLMN not allowed" response to a registration request
It receives a "GPRS not allowed" response to a registration request
Public Safety ProSe-enabled UEs using UE preconfigured resource shall not cause interference to a cell if the UE considers the cell as an acceptable cell and is operating as out-of-coverage as per the circumstances above.
The operator shall be able to authorise, via network control, Public Safety ProSe-enabled UEs to establish ProSe Communication when at least one of the two Public Safety ProSe-enabled UEs is served by EUTRAN.
The operator shall be able to pre-configure Public Safety ProSe-enabled UEs (e.g., in the USIM or ME) with the permission to use ProSe Discovery and/or Communication services for Public Safety, without the need for the Public Safety ProSe-enabled UEs to connect to the network to get this initial configuration. This requirement applies to any ProSe E-UTRA Communication between two Public Safety ProSe-enabled UEs, ProSe Group Communication and ProSe Broadcast Communication.
The system shall enable Public Safety ProSe-enabled UEs to mutually authenticate each other when not served by E-UTRAN.
Assuming Public Safety ProSe-enabled UEs are in Communication Range, are authenticated and are authorised, a Public Safety ProSe-enabled UE on public safety spectrum, whether or not it is served by E-UTRAN, shall be capable of establishing multiple one-to-one ProSe E-UTRA Communications using multiple ProSe E-UTRA Communication paths, and of exchanging user traffic with each Public Safety ProSe-enabled UE across these multiple paths.
A Public Safety ProSe-enabled ProSe-enabled UE, whether or not it is served by E-UTRAN shall be capable of transmitting data to a group of Public Safety ProSe-enabled UEs using ProSe Group Communications with a single transmission, assuming they are within Communication Range, authenticated and authorised.
Authentication shall allow for security-enablement of large groups, regardless whether group members have discovered each other when served by E-UTRAN or not.
A Public Safety ProSe-enabled UE whether or not it is served by E-UTRAN shall be capable of receiving a ProSe Group Communications transmission, of which it is a group member, regardless of whether or not it has been discovered by the transmitting Public Safety ProSe-enabled UE.
An authorised Public Safety ProSe-enabled UE, whether or not it is served by E-UTRAN shall be capable of sending a broadcast message to all authorised Public Safety ProSe-enabled UEs within Communication Range, regardless of group membership, using ProSe Broadcast Communication in a single transmission.
An authorised Public Safety ProSe-enabled UE, whether or not it is served by E-UTRAN, may be capable of acting as a relay for other public safety UEs.
An authorised Public Safety ProSe-enabled UE shall be capable of acting as a relay for ProSe E-UTRA Communication between two Public Safety ProSe-enabled UEs, ProSe Broadcast Communication, and ProSe Group Communication.
A ProSe UE-to-UE Relay shall be able to relay data for a group of Public Safety ProSe-enabled UEs using ProSe Group Communications regardless of their group membership.
An authorised Public Safety ProSe-enabled UE, whether or not it is served by E-UTRAN, shall be capable of being enabled/disabled by a user or the system to act as a relay for other Public Safety ProSe-enabled UEs.
The user of a Public Safety ProSe-enabled UE acting as a relay should not perceive service degradation due to its use as a relay, regardless whether or not the Public Safety ProSe-enabled UE is served by E-UTRAN.
There shall be a maximum of one ProSe UE-to-UE relay between two Public Safety ProSe-enabled UEs.
A ProSe UE-to-UE Relay serving as a relay for other Public Safety ProSe-enabled UE shall be able to be served at the same time by the UE serving as a relay for it.
A ProSe UE-to-UE Relay shall be capable of relaying communications for one or more Public Safety ProSe-enabled UEs that are within Communication Range of the ProSe UE-to-UE Relay.
A Public Safety ProSe-enabled UE shall be capable of acting as a relay regardless of whether or not it has been discovered by a Public Safety ProSe-enabled UE using it as a relay if they are within Communication Range.
In the case where communication is relayed by an Evolved ProSe UE-to-Network Relay between an E-UTRAN and a ProSe-enabled UE there shall be no ProSe UE-to-UE Relays between the ProSe-enabled UE and E-UTRAN.
An authorised Public Safety ProSe-enabled UE shall be capable of communication using both the network infrastructure and ProSe Communication with Public Safety ProSe-enabled UEs not served by E-UTRAN in parallel whether or not ProSe Discovery is used.
In addition, the system shall be able to move the user traffic session back to the EPC Path once the Public Safety ProSe-enabled UE is served by E-UTRAN. The user may inhibit the switch back to the EPC Path.
It is desirable that an authorised Public Safety ProSe-enabled UE, whether or not it is served by E-UTRAN, supports the capability to exchange data via ProSe from within a building to Public Safety ProSe-enabled UEs outside the building using a power class 3 E-UTRA UE [29].
Authorised Public Safety ProSe-enabled UEs, whether being served or not by E-UTRAN, shall be able to communicate with other authorised Public Safety ProSe-enabled UEs whether or not ProSe discovery is used.
A Public Safety ProSe-enabled UE shall provide the ability for the end user to activate/deactivate ProSe E-UTRA Communication whether or not the UE is served by E-UTRAN and whether or not ProSe discovery is used. This requirement applies to any ProSe E-UTRA Communication between two Public Safety ProSe-enabled UEs, and to ProSe Group Communication and ProSe Broadcast Communication.
A Public Safety ProSe-enabled UE shall support independent activation/deactivation of ProSe Discovery and ProSe E-UTRA Communication whether or not it is served by E-UTRAN. This requirement applies to any ProSe E-UTRA Communication between two Public Safety ProSe-enabled UEs, ProSe Group Communication and ProsSe Broadcast Communication.
Re-authorization and specific configurations, including spectrum configurations, of Public Safety ProSe-enabled UEs shall be subject to public safety operator policy.
An operator shall be able to configure a Public Safety ProSe-enabled UE with the permission to be discoverable or not by one or more Public Safety ProSe-enabled UEs, without prior registration to the network.
Subject to operator policy and/or network authorization, a user of a Public Safety ProSe-enabled UE shall be able to select the ProSe Communication path (direct or routed via local eNB) when the Public Safety ProSe-enabled UE is being served by E-UTRAN. This requirement applies to any ProSe E-UTRA Communication between two Public Safety ProSe-enabled UEs, ProSe Group Communication and ProSe Broadcast Communications. The network authorization shall consider the current traffic condition in the specific area.
A Public Safety ProSe-enabled UE shall be able to operate in spectrum allocated exclusively for ProSe and spectrum allocated for both ProSe and other services.
The Evolved Packet System shall support the following requirements for WLAN to enable ProSe communication.
Subject to operator policy and user consent, a ProSe-enabled UE with WLAN capability shall be able to establish ProSe-assisted WLAN direct communications with another ProSe-enabled UE when they are within WLAN direct communications range, based on ProSe Discovery and WLAN configuration information from the 3GPP EPC.
The 3GPP EPC shall be able to provide configuration information to ProSe-enabled UEs for the purpose of establishing ProSe-assisted WLAN direct communications.
The EPC shall be able to provide configuration information that enables confidentiality and integrity on the ProSe-assisted WLAN direct communications link.
The HPLMN operator shall be able to authorise ProSe-assisted WLAN direct communications for a ProSe-enabled UE, separately for use in the HPLMN and when roaming in VPLMNs.
The HPLMN operator shall be able to authorise a ProSe-enabled UE to engage in ProSe-assisted WLAN direct communications with a ProSe-enabled UE being served by a different PLMN.
The VPLMN operator shall be able to turn on or off ProSe-assisted WLAN direct communications for inbound roamers.
Both the HPLMN and VPLMN operators shall be able to charge for ProSe-assisted WLAN direct communications.
When a ProSe-enabled UE uses ProSe-assisted WLAN direct communications, both the HPLMN and VPLMN shall be able to collect accounting data for ProSe-assisted WLAN direct communications including:
ProSe-assisted WLAN direct communication duration, amount of data transferred, etc.
Subject to operator policy and user consent the EPC and a ProSe-enabled UE shall be capable of negotiating the move of a traffic flow between the EPC Path and the ProSe-assisted WLAN direct path.
There shall be no impact upon the RAN from service continuity procedures for ProSe-enabled UE traffic sessions that are moved between the infrastructure and WLAN direct communication paths.
The network shall be able to determine whether two ProSe-enabled UEs are within WLAN direct communications range and whether the WLAN direct link can provide the necessary QoS to support the end user application.
The network shall ensure service continuity for ProSe-assisted WLAN direct communications flows and be capable of considering QoS requirements of all data flows when negotiating a communications path switch for a given end user application.
The system shall be capable of establishing a new user traffic session for a ProSe-assisted WLAN direct communications path.
Subject to operator policy and user consent the EPS shall be capable of maintaining existing E-UTRAN infrastructure communications while ProSe-assisted WLAN direct communication is established by a given ProSe-enabled UE.
Subject to operator policy and user consent the EPS shall be capable of establishing new E-UTRAN infrastructure communications while ProSe WLAN communication is on-going for a given ProSe-enabled UE.
The EPC shall be able to request a UE to perform a path switch between the EPC Path and WLAN direct path for some or all of the UE's traffic sessions based on the load in the 3GPP network.
