WO2019095261A1

WO2019095261A1 - Methods and devices for group communication

Info

Publication number: WO2019095261A1
Application number: PCT/CN2017/111574
Authority: WO
Inventors: Jinyang Xie; Wu Wang; Jie LING
Original assignee: Telefonaktiebolaget LM Ericsson AB
Current assignee: Telefonaktiebolaget LM Ericsson AB
Priority date: 2017-11-17
Filing date: 2017-11-17
Publication date: 2019-05-23
Anticipated expiration: 2020-05-17

Abstract

A method implemented by an application server, AS, in a wireless communication network is provided. The AS may communicate with a plurality of user equipments, UEs, in the wireless communication network. The method comprises receiving a first group call request for a group call from a first UE of the plurality of UEs; determining, based on a predetermined policy, a need for at least one of sender reporting information from the first UE and reception reporting information from another UE of the plurality of UEs; in response to the need for the sender reporting information, enabling sender reporting by configuring a sender reporting field of a group call response to be transmitted to the first UE; and in response to the need for the reception reporting information, enabling reception reporting by configuring respective reception reporting fields of one or more second group call requests to be transmitted respectively to one or more UEs of the plurality of UEs other than the first UE. Accordingly, an application server for group communication in a wireless communication network is also provided.

Description

METHODS AND DEVICES FOR GROUP COMMUNICATION

TECHNICAL FIELD

The present disclosure generally relates to wireless communication networks, and more specifically to methods and devices for group communication.

BACKGROUND

This section introduces aspects that may facilitate better understanding of the disclosure. Accordingly, the statements of this section are to be read in this light and are not to be understood as admissions about what is in the prior art or what is not in the prior art.

Evolved Multimedia Broadcast Multicast Service (eMBMS) is a broadcasting service offered via Evolved Packet Systems (EPS) including Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) and UMTS Terrestrial Radio Access Network (UTRAN) access. E-UTRAN is utilized in Long Term Evolution (LTE) .

Fig. 1 is a schematic diagram illustrating an overview of an eMBMS system. Three typical scenarios exist in the eMBMS system. In a first scenario, media contents are delivered to user equipments (UEs) in a highly gathered area, e.g., in a stadium. The eMBMS system may use an MBMS download delivery method (User Datagram Protocol/File Delivery over Unidirectional Transport (UDP/FLUTE) ) as a protocol to deliver a live TV content to terminals. Media contents according to Dynamic Adaptive Streaming over HTTP (DASH) are delivered as segment files over MBMS download. In a second scenario, top on-demand files (e.g., Android update) are distributed to the UEs. The eMBMS system may use the MBMS download delivery method (UDP/FLUTE) as a protocol to deliver top popular files, such as Android update, YouTube clip preloading, top popular movies, etc. In a third scenario, UDP/IP packet flows are delivered to the UEs. A Broadcast Multicast Service Center (BM-SC) provides a group communication delivery by receiving UDP/IP packets and forwarding them over an MBMS path provided by an MBMS Bearer Service.

Mission critical applications become increasingly popular recently, including mission critical audio, video, data, files, etc. A typical service of the mission critical applications is Mission Critical Push to Talk (MCPTT) . In the conventional MCPTT, only unicast transmission is used. The unicast transmission is defined as transmission of data to a single network destination identified by a unique address. The unicast transmission uses dedicated radio resources, and it is triggered by an ender user as needed. Since the radio resources are limited in the mobile communication, a Quality of Experience (QoE) of the end user cannot always be guaranteed.

In MCPTT over LTE, LTE broadcast acts as an essential supplementary downlink delivery method to broadcast contents to a large number of subscribers simultaneously without delays or disconnections. The MCPTT service is required to support, in every cell of the MCPTT system, a minimum of 2000 MCPTT users within an MCPTT group or a combination of different MCPTT groups.

An MCPTT on-network architecture involving MBMS is illustrated in Fig. 2 by way of example. In Fig. 2, an MCPTT application server (AS) and a UE comprising an MCPTT client establish a unicast delivery using EPS bearers. The EPS bearers are mainly used for GC1 signaling between the MCPTT AS and the UE, communication of uplink data from the UE to the MCPTT AS, and communication of downlink data from the MCPTT AS to the UE if the MBMS delivery is infeasible or undesirable. As also shown in Fig. 2, the MCPTT AS and the UE establish an MBMS delivery using MBMS bearers. The MBMS bearers, which may be pre-established or dynamically established, may be used to communicate downlink data from the MCPTT AS to the UE. The MCPTT AS communicates with a BM-SC via an MB2 interface (including MB2-C for control plane signaling and MB2-U for user plane data) .

MCPTT users often monitor several groups in which a traffic pattern is characterized by:

-long periods of silence;

-short MCPTT group calls, which generally last 20-30 seconds;

-few talk bursts in each call, which generally include 4-8 talk bursts;

-a call setup time less than 300 milliseconds (ms) ; and

-a mouth-to-ear latency less than 300ms.

The MCPTT service is an end-to-end (E2E) delay critical service in which the mouth-to-ear latency should be less than 300ms. In the current MCPTT over LTE, however, measurement of an E2E delay is not defined.

Furthermore, as traffic is delivered over the air and through UDP packets, the UDP packets may be lost from the perspective of the E2E delay, whether through the unicast bearers or through the broadcast bearers. Reporting of confirmation information is not provided in the current MCPTT over LTE, especially for a group communication delivery in the mission critical service.

SUMMARY

It is an object of the present disclosure to define reporting information from clients and provide respective reports for the group communication delivery in the mission critical applications.

According to a first aspect of the present disclosure, a method implemented by an application server, AS, in a wireless communication network is provided. The AS may communicate with a plurality of user equipments, UEs, in the wireless communication network. The method comprises receiving a first group call request for a group call from a first UE of the plurality of UEs; determining, based on a predetermined policy, a need for at least one of sender reporting information from the first UE and reception reporting information from another UE of the plurality of UEs; in response to the need for the sender reporting information, enabling sender reporting by configuring a sender reporting field of a group call response to be transmitted to the first UE; and in response to the need for the reception reporting information, enabling reception reporting by configuring respective reception reporting fields of one or more second group call requests to be transmitted respectively to one or more UEs of the plurality of UEs other than the first UE.

In an alternative embodiment of the first aspect, the method may further comprise in response to the need for the sender reporting information: transmitting the group call response to the first UE; and receiving the sender reporting information from the first UE.

In a further alternative embodiment of the first aspect, the sender reporting information may be embedded into a first call release request received from the first UE.

In a further alternative embodiment of the first aspect, the group call response may further include a random time period field indicating a time window starting from a time at which a first call release request is transmitted from the first UE.

In a still further alternative embodiment of the first aspect, the sender reporting information may be received in a sender report transmitted at a random time selected by the first UE within the time window.

In an alternative embodiment of the first aspect, the method may further comprise in response to the need for the reception reporting information: transmitting the one or more second group call requests to the one or more UEs other than the first UE respectively; in response to receipt of a first call release request from the first UE, transmitting one or more second call release requests to the one or more UEs respectively; and receiving the reception reporting information from the one or more UEs respectively.

In a further alternative embodiment of the first aspect, the reception reporting information may be embedded into call release responses received from at least one UE of the one or more UEs.

In a further alternative embodiment of the first aspect, each of the second group call requests may further include a random time period field indicating a time window starting from a time at which the first call release request is transmitted from the first UE.

In a still further alternative embodiment of the first aspect, the reception reporting information may be received in each of one or more reception reports transmitted by a respective UE of the one or more UEs at a random time selected by the respective UE within the time window.

According to a second aspect of the present disclosure, a method implemented by a user equipment, UE, in a wireless communication network is provided. The UE may communicate with at least an application server, AS, in the wireless communication network. The method comprises transmitting a group call request for a group call to the AS; receiving a group call response from the AS including a sender reporting field; determining whether the sender reporting field is configured to enable sender reporting; and after a user of the UE initiates a release of the group call, in response to the sender reporting field being configured to enable the sender reporting, transmitting sender reporting information to the AS.

According to a third aspect of the present disclosure, a method implemented by a user equipment, UE, in a wireless communication network is provided. The UE may communicate with at least an application server, AS, in the wireless communication network. The method comprises receiving a group call request for a group call from the AS including a reception reporting field; determining whether the reception reporting field is configured to enable reception reporting; and in response to the reception reporting field being configured to enable the reception reporting, after receiving a first call release request from the AS, transmitting reception reporting information to the AS.

According to a fourth aspect of the present disclosure, an application server, AS, in a wireless communication network is provided. The AS may communicate with a plurality of user equipments, UEs, in the wireless communication network. The AS comprises a processor and a memory communicatively coupled to the processor. The memory is adapted to store instructions which, when executed by the processor, cause the AS to perform operations of the method according to the above first aspect.

According to a fifth aspect of the present disclosure, a user equipment, UE, in a wireless communication network is provided. The UE may communicate with at least an application server, AS, in the wireless communication network. The UE comprises a processor and a memory communicatively coupled to the processor. The memory is adapted to store instructions which, when executed by the processor, cause the UE to perform operations of the method according to the above second aspect.

According to a sixth aspect of the present disclosure, a user equipment, UE, in a wireless communication network is provided. The UE may communicate with at least an application server, AS, in the wireless communication network. The UE comprises a processor and a memory communicatively coupled to the processor. The memory is adapted to store instructions which, when executed by the processor, cause the UE to perform operations of the method according to the above third aspect.

According to a seventh aspect of the present disclosure, a wireless communication system is provided. The wireless communication system comprises: an application server, AS, according to the above first aspect; a user equipment, UE, according to the above second aspect, communicating with the AS; and one or more UEs according to the above third aspect, communicating with the AS.

According to an eighth aspect of the present disclosure, a non-transitory computer readable medium having a computer program stored thereon is provided. When the computer program is executed by a set of one or more processors of an application server, AS, the computer program causes the AS to perform operations of the method according to the above first aspect.

According to a ninth aspect of the present disclosure, a non-transitory computer readable medium having a computer program stored thereon is provided. When the computer program is executed by a set of one or more processors of a user equipment, UE, the computer program causes the UE to perform operations of the method according to the above second aspect.

According to a tenth aspect of the present disclosure, a non-transitory computer readable medium having a computer program stored thereon is provided. When the computer program is executed by a set of one or more processors of a user equipment, UE, the computer program causes the UE to perform operations of the method according to the above third aspect.

In the present disclosure, a client for a mission critical application, whether acting as a caller or as a callee, can provide the defined reporting information on the group communication delivery to the application server. Then, the applicant server can be fully aware of a Quality of Service (QoS) of the group communication delivery, including e.g. a packet loss in the uplink, an E2E delay contribution in the uplink, a packet loss in the downlink, an E2E delay contribution in the downlink, an efficiency of broadcast delivery usage, etc., based on the reporting information. In this way, network optimization, broadcast coverage optimization, broadcast area configuration optimization, broadcast service planning, etc. can be improved based on the QoS of the group communication delivery.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure may be best understood by way of example with reference to the following description and accompanying drawings that are used to illustrate embodiments of the present disclosure. In the drawings:

Fig. 1 is a schematic diagram illustrating an overview of an eMBMS system;

Fig. 2 is a schematic diagram illustrating an MCPTT on-network architecture involving MBMS;

Fig. 3 is an exemplary sequence diagram illustrating processes of a group communication according to some embodiments of the present disclosure;

Fig. 4 is a flow chart illustrating a method implemented on an AS according to some embodiments of the present disclosure;

Fig. 5 is a more specific flow chart illustrating a method implemented on an AS according to some embodiments of the present disclosure;

Fig. 6 is a flow chart illustrating a method implemented on a caller UE according to some embodiments of the present disclosure;

Fig. 7 is a flow chart illustrating a method implemented on a callee UE according to some embodiments of the present disclosure;

Fig. 8 is a block diagram illustrating an AS according to some embodiments of the present disclosure;

Fig. 9 is another block diagram illustrating an AS according to some embodiments of the present disclosure;

Fig. 10 is a block diagram illustrating a caller UE according to some embodiments of the present disclosure;

Fig. 11 is another block diagram illustrating a caller UE according to some embodiments of the present disclosure;

Fig. 12 is a block diagram illustrating a callee UE according to some embodiments of the present disclosure;

Fig. 13 is another block diagram illustrating a callee UE according to some embodiments of the present disclosure; and

Fig. 14 is a block diagram illustrating a wireless communication system according to some embodiments of the present disclosure.

DETAILED DESCRIPTION

The following detailed description describes methods and devices for group communication. In the following detailed description, numerous specific details such as logic implementations, types and interrelationships of system components, etc. are set forth in order to provide a more thorough understanding of the present disclosure. It should be appreciated, however, by one skilled in the art that the present disclosure may be practiced without such specific details. In other instances, control structures, circuits and instruction sequences have not been shown in detail in order not to obscure the present disclosure. Those of ordinary skill in the art, with the included descriptions, will be able to implement appropriate functionality without undue experimentation.

References in the specification to “one embodiment” , “an embodiment” , “an example embodiment” etc. indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

Bracketed text and blocks with dashed borders (e.g., large dashes, small dashes, dot-dash, and dots) may be used herein to illustrate optional operations that add additional features to embodiments of the present disclosure. However, such notation should not be taken to mean that these are the only options or optional operations, and/or that blocks with solid borders are not optional in certain embodiments of the present disclosure.

In the following detailed description and claims, the terms “coupled” and “connected, ” along with their derivatives, may be used. It should be understood that these terms are not intended as synonyms for each other. “Coupled” is used to indicate that two or more elements, which may or may not be in direct physical or electrical contact with each other, cooperate or interact with each other. “Connected” is used to indicate the establishment of communication between two or more elements that are coupled with each other.

An electronic device stores and transmits (internally and/or with other electronic devices over a network) code (which is composed of software instructions and which is sometimes referred to as computer program code or a computer program) and/or data using machine-readable media (also called computer-readable media) , such as machine-readable storage media (e.g., magnetic disks, optical disks, read only memory (ROM) , flash memory devices, phase change memory) and machine-readable transmission media (also called a carrier) (e.g., electrical, optical, radio, acoustical or other forms of propagated signals -such as carrier waves, infrared signals) . Thus, an electronic device (e.g., a computer) includes hardware and software, such as a set of one or more processors coupled to one or more machine-readable storage media to store code for execution on the set of processors and/or to store data. For instance, an electronic device may include non-volatile memory containing the code since the non-volatile memory can persist code/data even when the electronic device is turned off (when power is removed) , and while the electronic device is turned on, that part of the code that is to be executed by the processor (s) of that electronic device is typically copied from the slower non-volatile memory into volatile memory (e.g., dynamic random access memory (DRAM) , static random access memory (SRAM) ) of that electronic device. Typical electronic devices also include a set of one or more physical network interfaces to establish network connections (to transmit and/or receive code and/or data using propagating signals) with other electronic devices. One or more parts of an embodiment of the present disclosure may be implemented using different combinations of software, firmware, and/or hardware.

In the present disclosure, example processes, methods and devices are described with respect the MCPTT service. Nevertheless, they are not limited to being applied to the MCPTT, but also applicable to other mission critical applications including various mission critical audio, video, data, files, etc.

Fig. 3 is an exemplary sequence diagram illustrating processes of a group communication according to some embodiments of the present disclosure. A group communication system for the MCPTT over LTE is shown in Fig. 3, comprising at least an MCPTT client 301, an MCPTT AS 302, a group management server 303, and a plurality of MCPTT clients including at least an MCPTT client 304 and an MCPTT client 305. As an example, each of the

MCPTT clients

301, 304 and 305 may be included in a UE. For clarity of illustration, only the

callee clients

304 and 305 are shown in Fig. 3, but there may be more MCPTT clients acting as callees in the group communication. The processes illustrated in Fig. 3 are signaling control plane procedures. The

MCPTT clients

301, 304 and 305 belong to the same MCPTT group defined by the group management server 303.

After a user of the MCPTT client 301 initiates an MCPTT group call in step S 1, the client 301 may send an MCPTT group call request to the AS 302 in step S2. The AS 302 may record an identity of the user of the client 301 until the MCPTT is cancelled. The MCPTT group call request may contain an indication of an implicit floor request.

In step S3, the AS 302 may check whether the user of the client 301 is authorized to initiate an MCPTT call for the MCPTT group. If so, the AS 302 may resolve an MCPTT group ID of the MCPTT group to determine members of the MCPTT group and their affiliation statuses based on information from the group management server 303. Then in step S4, the AS 302 may decide whether sender reporting information from the client 301 is needed and/or whether reception reporting information from the other member clients is needed, based on a predetermined policy.

In step S5, the client 301 may send an MCPTT group call request to each of the member clients (e.g., clients 304 and 305) acting as callees. Ifit is determined in step S4 that the reception reporting information is needed, this group call request may include parameters for the reception reporting. In step S6, users of the

clients

304 and 305 which have received the group call requests may be notified of the incoming MCPTT group call, and start collecting statistics data for the reception reporting if the

clients

304 and 305 discover that the reception reporting information is needed.

In step S7, the

clients

304 and 305 may send group call responses to the AS 302. In step S8, the AS 302 may send a group call response to the client 301 to inform the client 301 of a successful call setup. Step S9 indicates that a notification may be sent by the AS 302 to the client 301 each time an MCPTT user joins or leaves the group call, i.e., the notification (s) may be sent to the client 301 more than once during the group call. Step S10 indicates that the

clients

301, 304 and 305 have successfully established a media plane for the group communication so that the client 301 can send media contents to the

clients

304 and 305.

After a user of the MCPTT client 301 initiates an MCPTT call release in step S11, the client 301 may send an MCPTT group call release request to the AS 302 in step S12. In one embodiment, the sender reporting information may be embedded into the group call release request.

In step S13, the client 301 may send group call release requests to the callee clients (e.g., the clients 304 and 305) . In step S14, the users of the

clients

304 and 305 which have received the group call release requests may be notified of the MCPTT call release, and prepare the reception reporting in the case that the reception reporting information is needed.

In step S15, the

clients

304 and 305 may send group call release responses to the AS 302. In one embodiment, the reception reporting information may be embedded into the group call release responses. In step S16, the AS 302 may send a group call response to the client 301 to confirm the group call release.

As an optional example, the sender reporting information may be sent by the client 301 to the AS 302 at a selected time in step S17. Also as an optional example, the reception reporting information may be sent by the

clients

304 and 305 to the AS 302 at selected times in step S18.

After receiving the sender reporting information and/or the reception reporting information, the AS 302 may analyze the reporting data in step S19 so as to e.g., derive the E2E delay for the group call, obtain broadcast delivery usage and/or broadcast delivery efficiency, perform network estimation based on the determined packet lost ratio in the group call, optimize a broadcast area based on traffic load of the group call, etc.

The processes of the sequence diagram will be described in greater detail with respect to the flow charts of Figs. 4-7 below.

Fig. 4 is a flow chart illustrating a method 400 implemented on an AS according to some embodiments of the present disclosure. As an example, the AS may be the MCPTT AS 302 as shown in Fig. 3 by way of example, but it is not limited thereto. The operations in this and other flow charts will be described with reference to the exemplary embodiments of the other figures. However, it should be appreciated that the operations of the flow charts may be performed by embodiments of the present disclosure other than those discussed with reference to the other figures, and the embodiments of the present disclosure discussed with reference to these other figures may perform operations different than those discussed with reference to the flow charts.

In one embodiment, the method 400 begins with the AS 302 receiving a group call request for a group call from a caller UE (block 401) . The caller UE may be a UE comprising the MCPTT client 301 as shown in Fig. 3 by way of example. After resolving an MCPTT group ID of the MCPTT group with the aid of a group management server (e.g., the group management server 303 as shown in Fig. 3) , the AS 302 may determine a need for sender reporting information from the caller UE and/or reception reporting information from other UEs (e.g., the UEs comprising the

MCPTT client

304 or 305 as shown in Fig. 3) in the MCPTT group based on a predefined policy (block 402) .

If the AS 302 determines that the sender reporting information is needed, before transmitting a group call response to the caller UE, the AS 302 may configure a sender reporting field of the group call response to enable sender reporting (block 403) . In addition to fields of MCPTT ID, MCPTT group ID and SDP answer, the group call response may further include a field of sender reporting, which is shown in Table I below:

Table I

The sender reporting field of the group call response may be set as a value ″disable″ by default, i.e., the sender reporting information is not needed. The AS 302 may configure the sender reporting field as a value ″enable″ to enable the sender reporting.

Likewise, if the AS 302 determines that the reception reporting information is needed, before transmitting group call requests to the other UEs, the AS 302 may configure respective reception reporting fields of the group call requests to enable reception reporting (block 404) . In addition to fields of MCPTT ID, MCPTT group ID, SDP offer, broadcast indicator and temporary group indicator, each of the group call requests may further include fields of reception reporting and random time period, which are shown in Table II below:

Table II

The reception reporting fields of the group call requests transmitted by the AS 302 to the callee UEs may be set as values ″disable″ by default, i.e., the reception reporting information is not needed. The AS 302 may configure the reception reporting fields as values ″enable″ to enable the reception reporting. As an example, the AS 302 may configure reception reporting fields of only some of the group call requests as ″enable″ , e.g., the group call request to the MCPTT client 304 is configured as ″enable″ but the group call request to the MCPTT client 305 is not configured as ″enable″ .

The random time period field may be described in detail with respect to Figs. 6 and 7 below.

Fig. 5 is a more specific flow chart illustrating a method implemented on an AS according to some embodiments of the present disclosure. As an example, the AS may be the MCPTT AS 302 as shown in Fig. 3 by way of example, but it is not limited thereto.

In one embodiment, the AS 302 may receive a group call request for a group call from a caller UE (block 501) . The caller UE may be a UE comprising the MCPTT client 301 as shown in Fig. 3 by way of example. The AS 302 may then determine a need for sender reporting information from the caller UE and/or reception reporting information from other UEs in the MCPTT group based on a predefined policy (block 502) . If the AS 302 determines that the sender reporting information is needed, before transmitting a group call response to the caller UE, the AS 302 may enable sender reporting by configuring a sender reporting field of the group call response (block 503) . As an example, information elements of the group call response may be shown above in Table I. Moreover, if the AS 302 determines that the reception reporting information is needed, before transmitting group call requests to the other UEs, the AS 302 may enable reception reporting by configuring respective reception reporting fields of the group call requests (block 504) . As an example, information elements of the group call requests to the other UEs may be shown above in Table II. The blocks 501-504 are corresponding to the blocks 401-404 of Fig. 4 respectively.

As an optional example, the AS 302 may transmit group call requests to one or more other ASs (block 505) , and these other ASs may further transmit the group call requests to one or more UEs for a group call across different servers. The group call requests to be transmitted to the one or more other ASs may also include fields of reception reporting and random time period, which are shown in Table III below:

Table III

Generally, in one embodiment, the AS 302 may transmit the group call requests with the reception reporting fields configured as ″enable″ (shown in Table II) directly to the one or more callee UEs of the MCPTT group (block 506) . These group call requests may notify users of the one or more callee UEs of the incoming MCPTT group call.

In one embodiment, towards the caller UE, the AS 302 may transmit the group call response including the sender reporting field configured as ″enable″ (shown in Table I) (block 507) .

After the group call is established, the user of the caller UE may initiate a release of the group call when the transmission finishes. Then, the AS 302 may receive the sender reporting information from the caller UE (block 509) . As an example, the AS 302 may receive the sender reporting information along with a group call release request from the caller UE. As another example, the AS 302 may receive the sender reporting information in a separate sender report from the caller UE some time later, e.g., within a time window starting from a time when the release request is transmitted by the caller UE. The time window may be defined by a random time period field (not shown in Table I) of the group call response transmitted by the AS 302 to the caller UE. The time to transmit the separate sender report is randomly selected by the caller UE within the time window.

After receiving the group call release request from the caller UE, the AS 302 may transmit group call release requests to the callee UEs (block 508) . Then, the AS 302 may receive the reception reporting information from the callee UEs (block 510) . As an example, the AS 302 may receive the reception reporting information along with a group call release response from each of the callee UEs. As another example, the AS 302 may receive the reception reporting information in a separate reception report from the callee UE later within a time window starting from a time when the initial group call release request is transmitted by the caller UE. The time window may be defined by a random time period field (shown in Table II) of the group call request transmitted by the AS 302 to the respective callee UE. The time to transmit the separate reception report is randomly selected by the respective callee UE within the time window, which will be described in more detail with respect to Fig. 7.

In one embodiment, the sender reporting information or the reception reporting information may include information elements as shown in Table IV below:

Table IV

In one embodiment, the sender reporting information or the reception reporting information may include at least a mission critical service identifier of the caller UE, a mission critical service group identifier on which the group call is requested, mission critical service client identifiers of the one or more callee UEs, locations of the UEs, a group conversation start time, and a group conversation end time.

As an example, if the mission critical service is associated with audio, video or data, the sender reporting information or the reception reporting information may further include a list of statistics of the group call. The list of statistics may include at least a media type, a sequence number of a first packet in the group call, a timestamp for the first packet in the group call, a sequence number of a last packet in the group call, a timestamp for the last packet in the group call, the total number of packets in the group call, and a total size of the packets in the group call. As a further example, for the callee UEs, the list of statistics of the reception reporting information may further include a broadcast delivery ratio, a packet loss ratio in broadcast delivery and a packet loss ratio in unicast delivery. Specifically, the broadcast deliver ratio may be defined as a ratio of the number of packets transmitted/received on a broadcast bearer to the total number of packets. The packet loss ratio in the broadcast delivery may be defined as a ratio of the number of lost packets on the broadcast bearer to the total number of packets on the broadcast bearer. The packet loss ratio in unicast delivery may be defined as a ratio of the number of lost packets on a unicast bearer to the total number of packets on the unicast bearer.

As another example, if the mission critical service is associated with a file, then the sender reporting information may further include a sender confirmation for the file, which may include at least a URI of the file, a size of the file and a sender status for the file; and the reception reporting information may further include a reception confirmation for a file, which may include at least a URI of the file, a size of the file, a reception status for the file, and a broadcast delivery ratio for the one or more callee UEs. As a further example, the sender confirmation or the reception confirmation may further include a packet loss ratio if the sender status or the reception status is failure.

With all of these information elements, the application server is able to perform network optimization, broadcast coverage optimization, broadcast area configuration optimization, broadcast service planning, etc. on the group communication delivery in a more efficient way.

Fig. 6 is a flow chart illustrating a method implemented on a caller UE according to some embodiments of the present disclosure. As an example, operations of this flow chart may be performed by a UE comprising the MCPTT client 301 as shown in Fig. 3.

In one embodiment, the caller UE may transmit a group call request for a group call to an AS, e.g., the MCPTT AS 302 as shown in Fig. 3 (block 601) . This identifies a start of the MCPTT group call conversation from the perspective of the caller UE. As an example, the group call request may be carried in a floor request message which may piggyback call control information flows to provide an efficient call setup.

After receiving a group call response from the AS including a sender reporting field (block 602) , the caller UE may determine whether the sender reporting field is configured as “enable” (block 603) . An example of information elements of the group call response may be found in Table I above.

Determination that the sender reporting field is configured as “enable” may mean a start for the caller UE to collect statistics data for the sender reporting. Thus, the caller UE may initiate collection of sender reporting information as soon as it determines that the sender reporting field is configured as “enable” (block 604) .

After a user of the caller UE initiates a release of the group call, the caller UE may transmit a group call release request to the AS. This identifies a completion of the MCPTT group call conversation from the perspective of the caller UE, and also means that the caller UE may stop collection of the statistics data for the sender reporting. As an example, the group call release request may be carried in a floor release message which may piggyback call control information flows to provide an efficient call setup.

The caller UE may transmit the sender reporting information to the AS. As an example, the caller UE may embed the sender reporting information into the group call release request and transmit the group call release request to the AS (block 605) . As another example, the caller UE may transmit the sender reporting information in a separated sender report later within a time window starting from a time when the group call release request is transmitted to the AS (block 606) . The time window may be defined by a random time period field of the group call response received by the caller UE. The time to transmit the separate sender report is randomly selected by the caller UE within the time window. For example, the caller UE may generate random or pseudo-random time dispersion of reports to the AS.

Examples of information elements of the sender reporting information may be found in Table IV above.

Fig. 7 is a flow chart illustrating a method implemented on a callee UE according to some embodiments of the present disclosure. As an example, operations of this flow chart may be performed by a UE comprising the

MCPTT client

304 or 305 as shown in Fig. 3.

In one embodiment, the callee UE may receive a group call request for a group call from an AS (e.g., the MCPTT AS 302 as shown in Fig. 3) including a reception reporting field (block 701) . This identifies a start of the MCPTT group call conversation from the perspective of the callee UE. As an example, the group call request may be carried in a floor taken message which may piggyback call control information flows to provide an efficient call setup.

Then, the callee UE may determine whether the reception reporting field is configured as “enable” (block 702) . An example of information elements of the group call request may be found in Table II above.

Determination that the reception reporting field is configured as “enable” may mean a start for the callee UE to collect statistics data for the reception reporting. Thus, the callee UE may initiate collection of reception reporting information as soon as it determines that the reception reporting field is configured as “enable” (block 703) .

After a media transmission, the callee UE may receive a group call release request from the AS. This identifies a completion of the MCPTT group call conversation from the perspective of the callee UE, and also means that the callee UE may stop collection of the statistics data for the reception reporting. As an example, the group call release request may be carried in a floor idle message which may piggyback call control information flows to provide an efficient call setup.

The callee UE may transmit the reception reporting information to the AS. As an example, the callee UE may embed the reception reporting information into a group call release response and transmit the group call release response to the AS (block 704) . As another example, the callee UE may transmit the reception reporting information in a separated reception report later within a time window starting from a time when an initial group call release request is transmitted by the caller UE to the AS (block 705) . The time window may be defined by a random time period field (shown in Table II) of the group call request received by the callee UE, and may be described as a back-off window. Back-off timing is used to spread loads of the reports from different callee UEs and to prevent crowdedness of the simultaneous reports. The time to transmit the separate reception report is randomly selected by the callee UE within the time window. For example, the callee UE may generate random or pseudo-random time dispersion of the reports to the AS.

The callee UE should send the reception reporting information in the random time window when the callee UE detects that the MCPTT is ended. The MCPTT communication may be terminated because the ender user of the callee UE stops listening or the callee UE is out of network coverage.

In one embodiment, the callee UE may transmit the reception reporting information even if it is aware that the group call has not been ended.

Examples of information elements of the reception reporting information may be found in Table IV above.

Fig. 8 is a block diagram illustrating an AS 800 according to some embodiments of the present disclosure. As an example, the AS 800 may be the MCPTT AS 302 as shown in Fig. 3, but it is not limited thereto. It should be appreciated that the AS 800 may be implemented using components other than those illustrated in Fig. 8.

With reference to Fig. 8, the AS 800 may comprise at least a processor 801, a memory 802, a network interface 803 and a communication medium 804. The processor 801, the memory 802 and the network interface 803 may be communicatively coupled to each other via the communication medium 804.

The processor 801 may include one or more processing units. A processing unit may be a physical device or article of manufacture comprising one or more integrated circuits that read data and instructions from computer readable media, such as the memory 802, and selectively execute the instructions. In various embodiments, the processor 801 may be implemented in various ways. As an example, the processor 801 may be implemented as one or more processing cores. As another example, the processor 801 may comprise one or more separate microprocessors. In yet another example, the processor 801 may comprise an application-specific integrated circuit (ASIC) that provides specific functionality. In still another example, the processor 801 may provide specific functionality by using an ASIC and/or by executing computer-executable instructions.

The memory 802 may include one or more computer-usable or computer-readable storage medium capable of storing data and/or computer-executable instructions. It should be appreciated that the storage medium is preferably a non-transitory storage medium.

The network interface 803 may be a device or article of manufacture that enables the AS 800 to send data to or receive data from the UEs. In different embodiments, the network interface 803 may be implemented in different ways. As an example, the network interface 803 may be implemented as an Ethernet interface, a token-ring network interface, a fiber optic network interface, a wireless network interface (e.g., Wi-Fi, WiMax, etc. ) , or another type of network interface.

The communication medium 804 may facilitate communication among the processor 801, the memory 802 and the network interface 803. The communication medium 804 may be implemented in various ways. For example, the communication medium 804 may comprise a Peripheral Component Interconnect (PCI) bus, a PCI Express bus, an accelerated graphics port (AGP) bus, a serial Advanced Technology Attachment (ATA) interconnect, a parallel ATA interconnect, a Fiber Channel interconnect, a USB bus, a Small Computing System Interface (SCSI) interface, or another type of communications medium.

In the example of Fig. 8, the instructions stored in the memory 802 may include those that, when executed by the processor 801, cause the AS 800 to implement the methods described with respect to Figs. 4 and 5.

Fig. 9 is another block diagram illustrating an AS 900 according to some embodiments of the present disclosure. As an example, the AS 900 may be the MCPTT AS 302 as shown in Fig. 3, but it is not limited thereto. It should be appreciated that the AS 900 may be implemented using components other than those illustrated in Fig. 9.

With reference to Fig. 9, the AS 900 may comprise at least a request receiving unit 901, a determination unit 902 and a configuration unit 903. The request receiving unit 901 may be adapted to perform at least the operations described in the block 401 of Fig. 4 and in the block 501 of Fig. 5. As an example, the request receiving unit 901 may also be adapted to perform at least the operation described in the block 509 of Fig. 5 when the sender reporting information is embedded in a group call release request. The determination unit 902 may be adapted to perform at least the operations described in the block 402 of Fig. 4 and in the block 502 of Fig. 5. The configuration unit 903 may be adapted to perform at least the operations described in the

blocks

403 and 404 of Fig. 4 and in the

blocks

503 and 504 of Fig. 5.

In one embodiment, the AS 900 may further comprise a response transmission unit 904, a report receiving unit 905, a request transmission unit 906 and a response receiving unit 907. The response transmission unit 904 may be adapted to perform at least the operation described in the block 507 of Fig. 5. The report receiving unit 905 may be adapted to perform at least the operations described in the

blocks

509 and 510 of Fig. 5 when the reporting information are received in a separate report. The request transmission unit 906 may be adapted to perform at least the operations described in the

blocks

505, 506 and 508 of Fig. 5. The response receiving unit 907 may be adapted to perform at least the operation described in the block 510 of Fig. 5 when the reception reporting information is embedded into a group call release response.

Fig. 10 is a block diagram illustrating a UE 1000 according to some embodiments of the present disclosure. As an example, the UE 1000 may act as a UE comprising the MCPTT client 301 as shown in Fig. 3. It should be appreciated that the UE 1000 may be implemented using components other than those illustrated in Fig. 10.

With reference to Fig. 10, the UE 1000 may comprise at least a processor 1001, a memory 1002, a network interface 1003 and a communication medium 1004. The processor 1001, the memory 1002 and the network interface 1003 are communicatively coupled to each other via the communication medium 1004.

The processor 1001, the memory 1002, the network interface 1003 and the communication medium 1004 are structurally similar to the processor 801, the memory 802, the network interface 803 and the communication medium 804 respectively, and will not be described herein in detail.

In the example of Fig. 10, the instructions stored in the memory 1002 may include those that, when executed by the processor 1001, cause the UE 1000 to implement the method described with respect to Fig. 6.

Fig. 11 is another block diagram illustrating a UE 1100 according to some embodiments of the present disclosure. As an example, the UE 1100 may act as a UE comprising the MCPTT client 301 as shown in Fig. 3. It should be appreciated that the UE 1100 may be implemented using components other than those illustrated in Fig. 11.

With reference to Fig. 11, the UE 1100 may comprise at least a request transmission unit 1101, a response receiving unit 1102, a determination unit 1103 and a report transmission unit 1104. The request transmission unit 1101 may be adapted to perform at least the operations described in the

blocks

601 and 605 of Fig. 6. The response receiving unit 1102 may be adapted to perform at least the operation described in the block 602 of Fig. 6. The determination unit 1103 may be adapted to perform at least the operation described in the block 603 of Fig. 6. The report transmission unit 1104 may be adapted to perform at least the operation described in the block 606 of Fig. 6.

In one embodiment, the UE 1100 may further comprise a data collection unit 1105 adapted to perform at least the operation described in the block 604 of Fig. 6.

Fig. 12 is a block diagram illustrating a UE 1200 according to some embodiments of the present disclosure. As an example, the UE 1200 may act as a UE comprising the

MCPTT client

304 or 305 as shown in Fig. 3. It should be appreciated that the UE 1200 may be implemented using components other than those illustrated in Fig. 12.

With reference to Fig. 12, the UE 1200 may comprise at least a processor 1201, a memory 1202, a network interface 1203 and a communication medium 1204. The processor 1201, the memory 1202 and the network interface 1203 are communicatively coupled to each other via the communication medium 1204.

The processor 1201, the memory 1202, the network interface 1203 and the communication medium 1204 are structurally similar to the

processor

801 or 1001, the

memory

802 or 1002, the

network interface

803 or 1003 and the

communication medium

804 or 1004 respectively, and will not be described herein in detail.

In the example of Fig. 12, the instructions stored in the memory 1202 may include those that, when executed by the processor 1201, cause the UE 1200 to implement the method described with respect to Fig. 7.

Fig. 13 is another block diagram illustrating a UE 1300 according to some embodiments of the present disclosure. As an example, the UE 1300 may act as a UE comprising the

MCPTT client

304 or 305 as shown in Fig. 3.It should be appreciated that the UE 1300 may be implemented using components other than those illustrated in Fig. 13.

With reference to Fig. 13, the UE 1300 may comprise at least a request receiving unit 1301, a determination unit 1302, a response transmission unit 1303 and a report transmission unit 1304. The request receiving unit 1301 may be adapted to perform at least the operation described in the block 701 of Fig. 7. The determination unit 1302 may be adapted to perform at least the operation described in the block 702 of Fig. 7. The response transmission unit 1303 may be adapted to perform at least the operation described in the block 704 of Fig. 7. The report transmission unit 1304 may be adapted to perform at least the operation described in the block 705 of Fig. 7.

In one embodiment, the UE 1300 may further comprise a data collection unit 1305 adapted to perform at least the operation described in the block 703 of Fig. 7.

The units 901-907, 1101-1105 and 1301-1305 are illustrated as separate units in Figs. 9, 11 and 13. However, this is merely to indicate that the functionality is separated. The units may be provided as separate elements. However, other arrangements are possible, e.g., some of them may be combined as one unit in each figure. Any combination of the units may be implemented in any combination of software, hardware, and/or firmware in any suitable location. For example, there may be more controllers configured separately, or just one controller for all of the components.

The units shown in Figs. 9, 11 and 13 may constitute machine-executable instructions embodied within a machine, e.g., readable medium, which when executed by a machine will cause the machine to perform the operations described. Besides, any of these units may be implemented as hardware, such as an application specific integrated circuit (ASIC) , Digital Signal Processor (DSP) , Field Programmable Gate Array (FPGA) or the like.

Moreover, it should be appreciated that the arrangements described herein are set forth only as examples. Other arrangements (e.g., more controllers or more detectors, etc. ) may be used in addition to or instead of those shown, and some units may be omitted altogether. Functionality and cooperation of these units are correspondingly described in more detail with reference to Figs. 4-7.

Fig. 14 is a block diagram illustrating a wireless communication system 1400 for group communication according to some embodiments of the present disclosure. The wireless communication system 1400 comprises at least an AS 1401, a UE 1402, and one or more UEs 1403. In one embodiment, the AS 1401 may act as the AS 800 as depicted in Fig. 8. In one embodiment, the UE 1402 may act as the UE 1000 as depicted in Fig. 10. In one embodiment, each of the UEs 1403 may act as the UE 1200 as depicted in Fig. 12.

As an example, the wireless communication system 1400 may further comprise one or more other ASs 1401′each serving one or more callee UEs 1403′to realize a group communication across various application servers.

Some portions of the foregoing detailed description have been presented in terms of algorithms and symbolic representations of transactions on data bits within a computer memory. These algorithmic descriptions and representations are ways used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. An algorithm is here, and generally, conceived to be a self-consistent sequence of transactions leading to a desired result. The transactions are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated. It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like.

It should be appreciated, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise as apparent from the above discussion, it is appreciated that throughout the description, discussions utilizing terms such as ″processing″ or ″computing″ or ″calculating″ or ″determining″ or ″displaying″ or the like, refer to actions and processes of a computer system, or a similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system′s registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices.

The algorithms and displays presented herein are not inherently related to any particular computer or other apparatus. Various general-purpose systems may be used with programs in accordance with the teachings herein, or it may prove convenient to construct more specialized apparatus to perform the required method transactions. The required structure for a variety of these systems will appear from the description above. In addition, embodiments of the present disclosure are not described with reference to any particular programming language. It should be appreciated that a variety of programming languages may be used to implement the teachings of embodiments of the present disclosure as described herein.

An embodiment of the present disclosure may be an article of manufacture in which a non-transitory machine-readable medium (such as microelectronic memory) has stored thereon instructions (e.g., computer code) which program one or more data processing components (generically referred to here as a “processor” ) to perform the operations described above. In other embodiments, some of these operations might be performed by specific hardware components that contain hardwired logic (e.g., dedicated digital filter blocks and state machines) . Those operations might alternatively be performed by any combination of programmed data processing components and fixed hardwired circuit components.

In the foregoing detailed description, embodiments of the present disclosure have been described with reference to specific exemplary embodiments thereof. It will be evident that various modifications may be made thereto without departing from the spirit and scope of the present disclosure as set forth in the following claims. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense.

Throughout the description, some embodiments of the present disclosure have been presented through flow diagrams. It should be appreciated that the order of transactions and transactions described in these flow diagrams are only intended for illustrative purposes and not intended as a limitation of the present disclosure. One having ordinary skill in the art would recognize that variations can be made to the flow diagrams without departing from the spirit and scope of the present disclosure as set forth in the following claims.

Claims

A method (400) implemented by an application server, AS, in a wireless communication network, the AS communicating with a plurality of user equipments, UEs, in the wireless communication network, the method comprising:

receiving a first group call request for a group call from a first UE of the plurality of UEs (401, 501) ；

determining, based on a predetermined policy, a need for at least one of sender reporting information from the first UE and reception reporting information from another UE of the plurality of UEs (402, 502) ；

in response to the need for the sender reporting information, enabling sender reporting by configuring a sender reporting field of a group call response to be transmitted to the first UE (403, 503) ； and

in response to the need for the reception reporting information, enabling reception reporting by configuring respective reception reporting fields of one or more second group call requests to be transmitted respectively to one or more UEs of the plurality of UEs other than the first UE (404, 504) .
The method of Claim 1, further comprising:

in response to the need for the sender reporting information,

transmitting the group call response to the first UE (507) ； and

receiving the sender reporting information from the first UE (509) .
The method of Claim 2, wherein the sender reporting information is embedded into a first call release request received from the first UE.
The method of Claim 2, wherein the group call response further includes a random time period field indicating a time window starting from a time at which a first call release request is transmitted from the first UE.
The method of Claim 4, wherein the sender reporting information is received in a sender report transmitted at a random time selected by the first UE within the time window.
The method of Claim 1, further comprising:

in response to the need for the reception reporting information,

transmitting the one or more second group call requests to the one or more UEs other than the first UE respectively (506) ；

in response to receipt of a first call release request from the first UE, transmitting one or more second call release requests to the one or more UEs respectively (508) ； and

receiving the reception reporting information from the one or more UEs respectively (510) .
The method of Claim 6, wherein the reception reporting information is embedded into call release responses received from at least one UE of the one or more UEs.
The method of Claim 6, wherein each of the second group call requests further includes a random time period field indicating a time window starting from a time at which the first call release request is transmitted from the first UE.
The method of Claim 8, wherein the reception reporting information is received in each of one or more reception reports transmitted by a respective UE of the one or more UEs at a random time selected by the respective UE within the time window.
The method of Claim 6, further comprising:

transmitting the one or more second group call requests to one or more other ASs serving the one or more UEs (505) .
The method of any of Claims 1 to 10, wherein the sender reporting information or the reception reporting information includes at least the following: a mission critical service identifier of the first UE, a mission critical service group identifier on which the group call is requested, mission critical service client identifiers of the one or more UEs, locations of the UEs, a group conversation start time, and a group conversation end time.
The method of Claim 11, wherein the sender reporting information or the reception reporting information further includes a list of statistics of the group call, which includes at least the following: a media type, a sequence number of a first packet in the group call, a timestamp for the first packet in the group call, a sequence number of a last packet in the group call, a timestamp for the last packet in the group call, the total number of packets in the group call, and a total size of the packets in the group call.
The method of Claim 12, wherein the list of statistics of the reception reporting information further includes a broadcast delivery ratio, a packet loss ratio in broadcast delivery and a packet loss ratio in unicast delivery for the one or more UEs of the plurality of UEs other than the first UE.
The method of Claim 11, wherein the sender reporting information further includes a sender confirmation for a file, which includes at least a uniform resource identifier of the file, a size of the file and a sender status for the file, and wherein the reception reporting information further includes a reception confirmation for a file, which includes at least a uniform resource identifier of the file, a size of the file, a reception status for the file, and a broadcast delivery ratio for the one or more UEs of the plurality of UEs other than the first UE.
The method of Claim 14, wherein the sender or reception confirmation further includes a packet loss ratio if the sender or reception status is failure.
A method (600) implemented by a user equipment, UE, in a wireless communication network, the UE communicating with at least an application server, AS, in the wireless communication network, the method comprising:

transmitting a group call request for a group call to the AS (601) ；

receiving a group call response from the AS including a sender reporting field (602) ；

determining whether the sender reporting field is configured to enable sender reporting (603) ； and

after a user of the UE initiates a release of the group call, in response to the sender reporting field being configured to enable the sender reporting, transmitting sender reporting information to the AS (605, 606) .
The method of Claim 16, further comprising:

upon determination that the sender reporting field is configured to enable the sender reporting, initiating collection of the sender reporting information (604) .
The method of Claim 17, wherein the collection of the sender reporting information is ended when transmitting a call release request to the AS.
The method of Claim 16, wherein the sender reporting information is embedded into a call release request to be transmitted to the AS (605) .
The method of Claim 16, wherein the group call response further includes a random time period field indicating a time window starting from a time at which a call release request is transmitted to the AS.
The method of Claim 20, wherein transmitting the sender reporting information comprises:

transmitting a sender report at a random time selected by the UE within the time window (606) .
The method of any of Claims 16 to 21, wherein the sender reporting information includes at least the following: a mission critical service identifier of the UE, a mission critical service group identifier on which the group call is requested, mission critical service client identifiers of one or more other UEs in the group call, locations of the UEs, a group conversation start time, and a group conversation end time.
The method of Claim 22, wherein the sender reporting information further includes a list of statistics of the group call, which includes at least the following: a media type, a sequence number of a first packet in the group call, a timestamp for the first packet in the group call, a sequence number of a last packet in the group call, a timestamp for the last packet in the group call, the total number of packets in the group call, and a total size of the packets in the group call.
The method of Claim 22, wherein the sender reporting information further includes a sender confirmation for a file, which includes at least a uniform resource identifier of the file, a size of the file and a sender status for the file.
The method of Claim 24, wherein the sender confirmation further includes a packet loss ratio if the sender status is failure.
A method (700) implemented by a user equipment, UE, in a wireless communication network, the UE communicating with at least an application server, AS, in the wireless communication network, the method comprising:

receiving a group call request for a group call from the AS including a reception reporting field (701) ；

determining whether the reception reporting field is configured to enable reception reporting (702) ； and

in response to the reception reporting field being configured to enable the reception reporting, after receiving a first call release request from the AS, transmitting reception reporting information to the AS (704, 705) .
The method of Claim 26, further comprising:

upon determination that the reception reporting field is configured to enable the reception reporting, initiating collection of the reception reporting information (703) .
The method of Claim 27, wherein the collection of the reception reporting information is ended when receiving the first call release request.
The method of Claim 26, wherein the reception reporting information is embedded in a call release response to be transmitted to the AS (704) .
The method of Claim 26, wherein the group call request further includes a random time period field indicating a time window starting from a time at which a second call release request is transmitted to the AS by a UE which initiates the group call.
The method of Claim 30, wherein transmitting the reception reporting information comprises:

transmitting a reception report at a random time selected by the UE within the time window (705) .
The method of any of Claims 26 to 31, wherein the reception reporting information includes at least the following: a mission critical service identifier of a UE which initiates the group call, a mission critical service group identifier on which the group call is requested, mission critical service client identifiers of one or more UEs which receive group call requests from the AS, locations of the UEs, a group conversation start time, and a group conversation end time.
The method of Claim 32, wherein the reception reporting information further includes a list of statistics of the group call, which includes at least the following: a media type, a sequence number of a first packet in the group call, a timestamp for the first packet in the group call, a sequence number of a last packet in the group call, a timestamp for the last packet in the group call, the total number of packets in the group call, and a total size of the packets in the group call.
The method of Claim 33, wherein the list of statistics further includes a broadcast delivery ratio, a packet loss ratio in broadcast delivery and a packet loss ratio in unicast delivery for the one or more UEs.
The method of Claim 32, wherein the reception reporting information further includes a reception confirmation for a file, which includes at least a uniform resource identifier of the file, a size of the file, a reception status for the file, and a broadcast delivery ratio for the one or more UEs.
The method of Claim 35, wherein the reception confirmation further includes a packet loss ratio if the reception status is failure.
An application server, AS, (800) in a wireless communication network, the AS communicating with a plurality of user equipments, UEs, in the wireless communication network, and the AS comprising:

a processor (801) ； and

a memory (802) communicatively coupled to the processor and adapted to store instructions which, when executed by the processor, cause the AS to perform operations of the method of any of Claims 1 to 15.
A user equipment, UE, (1000) in a wireless communication network, the UE communicating with at least an application server, AS, in the wireless communication network, and the UE comprising:

a processor (1001) ； and

a memory (1002) communicatively coupled to the processor and adapted to store instructions which, when executed by the processor, cause the UE to perform operations of the method of any of Claims 16 to 25.
A user equipment, UE, (1200) in a wireless communication network, the UE communicating with at least an application server, AS, in the wireless communication network, and the UE comprising:

a processor (1201) ； and

a memory (1202) communicatively coupled to the processor and adapted to store instructions which, when executed by the processor, cause the UE to perform operations of the method of any of Claims 26 to 36.
A wireless communication system (1400) , comprising:

an application server, AS, (1401) of Claim 37；

a user equipment, UE, (1402) of Claim 38, communicating with the AS； and

one or more UEs (1403) of Claim 39, communicating with the AS.
A non-transitory computer readable medium having a computer program stored thereon which, when executed by a set of one or more processors of an application server, AS, communicating with a plurality of user equipments, UEs, in a wireless communication network, causes the AS to perform operations of the method of any of Claims 1 to 15.
A non-transitory computer readable medium having a computer program stored thereon which, when executed by a set of one or more processors of a user equipment, UE, communicating with at least an application server, AS, in a wireless communication network, causes the UE to perform operations of the method of any of Claims 16 to 25.
A non-transitory computer readable medium having a computer program stored thereon which, when executed by a set of one or more processors of a user equipment, UE, communicating with at least an application server, AS, in a wireless communication network, causes the UE to perform operations of the method of any of Claims 26 to 36.