METHOD AND APPARATUS FOR MANAGING MULTICAST RESOURCE

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application Nos. 10-2012-0022939 and 10-2013-0023128 filed in the Korean Intellectual Property Office on Mar. 6, 2012 and Mar. 5, 2013, respectively, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention generally relates to a method and an apparatus for managing a multicast resource.

(b) Description of the Related Art

A multicast communication is used to a group communication where the same service is provided to a plurality of users at the same time. In the group communication, the same downlink traffic is simultaneously transmitted to all the users in a group for the group communication. Therefore, the users joining the group communication use a multicast connection to transmit data of the group communication.

A robust modulation and coding scheme (MCS) can be used to provide a reliable service regardless of positions of users receiving the multicast service. However, although the robust MCS can efficiently provide the multicast service to many users, it has restrictions for providing the multicast service by limited resource.

SUMMARY OF THE INVENTION

An embodiment of the present invention provides a multicast resource management method and apparatus for efficiently providing a limited resource to a plurality of users.

According to another embodiment of the present invention, a method of managing a multicast resource is provided by a base station. The method includes allocating a multicast resource to a multicast group, generating a MAP information element (MAP IE) including information of the multicast resource and a transmission indication for indicating whether the multicast resource is fragmented, and transmitting the MAP IE to the multicast group.

When the multicast traffic is fragmented, the transmission indication may indicate which of fragmented traffics is transmitted by the multicast resource.

A first value of the transmission indication may indicate that no fragmented traffic is transmitted, a second value of the transmission indication may indicate that the first fragmented traffic is transmitted from among fragmented traffics, a third value of the transmission indication may indicate that the second to second last fragmented traffic are transmitted from among the fragmented traffics, and a fourth value of the transmission indication may indicate that the last fragmented traffic is transmitted from among the fragmented traffics.

The MAP IE may further include an allocation period indicating a period in which the multicast resource is allocated, and a lifetime in which allocation of the multicast resource is maintained.

The MAP IE excluding the transmission indication may not change unless the lifetime expires.

The method may further include transmitting a next MAP IE including new allocation information on the multicast resource to the multicast group when the lifetime expires.

According to yet another embodiment of the present invention, a method of managing a multicast resource is provided by a mobile station. The method includes receiving from a base station a MAP IE including information of the multicast resource and a transmission indication for indicating whether the multicast resource is fragmented, and identifying whether the multicast resource is fragmented by using the transmission indication.

When the multicast traffic is fragmented, the transmission indication may indicate which of fragmented traffics is transmitted by the multicast resource.

The MAP IE may further include an allocation period indicating a period in which the multicast resource is allocated, and a lifetime in which allocation of the multicast resource is maintained.

The MAP IE excluding the transmission indication may not change unless the lifetime expires.

The method may further include receiving a next MAP IE including new allocation information on the multicast resource when the lifetime expires.

According to yet another embodiment of the present invention, an apparatus for managing a multicast resource is provided. The apparatus includes a resource manager configured to allocate multicast resource to a multicast group and to generate a MAP IE including information of the multicast resource and a transmission indication for indicating whether the multicast resource is fragmented, and a transmitter configured to transmit the MAP IE to the multicast group.

The MAP IE may further include an allocation period indicating a period in which the multicast resource is allocated, and a lifetime in which allocation of the multicast resource is maintained.

The MAP IE excluding the transmission indication may not change unless the lifetime expires.

According to yet another embodiment of the present invention, an apparatus for managing a multicast resource is provided. The apparatus includes a receiver configured to receive from a base station a MAP IE including information of the multicast resource and a transmission indication for indicating whether the multicast resource is fragmented, and a controller configured to identify whether the multicast resource is fragmented by using the transmission indication.

The MAP IE may further include an allocation period indicating a period in which the multicast resource is allocated, and a lifetime in which allocation of the multicast resource is maintained.

The MAP IE excluding the transmission indication may not change unless the lifetime expires.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 to FIG. 3 show a multicast communication system according to embodiments of the present invention.

FIG. 4 shows a multicast connection establishment method according to an embodiment of the present invention.

FIG. 5 is a flowchart of a multicast resource management method according to an embodiment of the present invention.

FIG. 6 shows an example of a multicast resource management method according to an embodiment of the present invention.

FIG. 7 and FIG. 8 are a block diagram of a multicast resource management apparatus according to embodiments of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In the following detailed description, only certain embodiments of the present invention have been shown and described, simply by way of illustration. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. Accordingly, the drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements throughout the specification.

In the specification, the term “mobile station (MS)” may designate a terminal, a mobile terminal (MT), an advanced mobile station (AMS), a high reliability mobile station (HR-MS), a subscriber station (SS), a portable subscriber station (PSS), an access terminal (AT), a user equipment (UE), and so on, or may include all or some functions thereof.

Further, the term “base station” (BS) may designate an advanced base station (ABS), a high reliability base station (HR-BS), a node B, an evolved node B (eNodeB), an access point (AP), a radio access station (RAS), a base transceiver station (BTS), an MMR (mobile multihop relay)-BS, a relay station (RS) performing base station function, a relay node (RN) performing base station function, an advanced relay station (ARS) performing base station function, a high reliability relay station (HR-RS) performing the base station function, a small cell BS (femto BS, home node B (HNB), pico BS, metro BS, micro BS, and so on), and so on, or may include all or some functions thereof.

FIG. 1 shows a multicast communication system according to an embodiment of the present invention.

Referring to FIG. 1, a base station 110 uses a multicast group identifier (ID) allocated to a multicast group 120, to provide the multicast group 120 including a plurality of mobile stations with a multicast communication. The multicast group ID is uniquely allocated within the base station 110 and has a finite size. The multicast group ID is used as an ID for notifying the multicast group of the allocated resource. Other multicast groups 120, 130, and 140 have different multicast group ID MGID_A, MGID_B, and MGID_C.

The base station 110 uses a flow identifier (FID) for identifying a connection besides the multicast group ID. The base station 110 allocates the FID in each multicast group ID, thereby uniquely identifying the connection, i.e., a service flow within the multicast group. Since the FID is an ID for identifying a signal or traffic connection within the multicast group, a particular connection of the multicast group can be identified a combination of the multicast group ID and FID in the base station 110. That is, the base station 110 uses the multicast group ID and the FID to provide the multicast group 120 with a multicast service. The same FID (FID0 or FID1) may be used in the other multicast groups 120, 130, and 140.

FIG. 2 shows a multicast communication system another embodiment of the present invention.

Referring to FIG. 2, a base station 210 uses a multicast group ID to provide a multicast group 220 including a plurality of mobile stations with the multicast service. The multicast group ID is uniquely allocated for identifying a connection, i.e., a service flow of the multicast group, and has a finite size. This multicast group ID may have a greater size than the multicast group ID described in FIG. 1, in order to identify the service flow as well as the multicast group. For example, the multicast group ID of FIG. 1 may have 12 bits, and the multicast group ID of FIG. 2 may have 16 bits.ID

Other multicast group IDs (MGID0, MGID1, MGID2, MGID3, MGID4, and MGID5) are used in different multicast groups 220, 230, and 240. A multicast resource allocated to the multicast service can be notified to the multicast group through the multicast group ID.

FIG. 3 shows a multicast communication system according to yet another embodiment of the present invention.

Referring to FIG. 3, a multicast group zone is defined as a base station set including at least one base station in a group communication system according to an embodiment of the present invention. A unique multicast group zone ID is allocated to the multicast group zone. A multicast group ID having a unique value is allocated to a multicast group within the multicast group zone, and a multicast service can be identified using an FID within the multicast group. That is, the multicast service that is provided within the multicast group zone can be identified using the multicast group ID and FID. Alternatively, a multicast group ID having a unique value is allocated to a multicast group within the multicast group zone, and a multicast service that is provided within the multicast group zone can be identified using the multicast group ID.

In the multicast group zone, a set of base stations uses the same multicast group ID and FID or the same multicast group ID for transmitting data of a certain service flow. Accordingly, if a mobile station has already registered with a base station for a multicast service, the mobile station can be seamlessly receive the multicast service without reregistering with other base station even if the mobile station moves to the other base station within the same multicast group zone. If the mobile station moves from a base station to another base station, those base stations provide the same multicast service but belong to different multicast group zone, the mobile station can seamlessly receive the multicast service by updating a parameter associated with the multicast service.

If only one base station belongs to a multicast group zone, the single base station uses a multicast group ID for providing a multicast service, independently from other base stations.

FIG. 4 shows a multicast connection establishment method according to an embodiment of the present invention.

Referring to FIG. 4, a mobile station 41 transmits a registration request (REG-REQ) message and a base station 42 transmits a registration response (REG-RSP) message to the mobile station 41 in response to the REG-REQ message (S410). To discover a multicast service, the mobile station 41 informs the base station 42 of support of multicast transmission by the REG-REQ message and the base station 42 registers the mobile station 41 by the REG-RSP message.

When the mobile station 41 registers to receive the multicast service, either the mobile station 41 or the base station 42 initiates a dynamic service addition (DSA) procedure for a multicast connection service (S420). The one node of the mobile station 41 and the base station 42 transmits a DSA-REQ message to the other node and receives a DSA-RSP message from the other node such that the multicast connection is established.

The DSA-REQ and DSA-RSP messages include a multicast parameter associated with the multicast service. The multicast parameter includes a multicast group ID of a multicast group to which a service flow is added. The multicast parameter may further include a FID associated with the multicast group ID.

Further, when a multicast group zone is supported, the multicast parameter may further include a multicast group zone ID where the service flow is valid. The mobile station 41 can add the service flow for starting a multicast service by the multicast parameter. Alternatively, the base station may periodically broadcast a multicast group zone ID through a broadcast message. If the multicast group zones are not locally overlapped with each other and are identified from each other (that is, a base station belongs to only one multicast group zone or the multicast group zone is not defined), the multicast parameter of the DSA-REQ or DSA-RSP message may not include multicast group zone ID.

The mobile station 41 and the base station 42 may not exchange a multicast service capability in the REQ-REQ/RSP exchange procedure (S410) but exchange the multicast service capability in the DSA-REQ/RSP exchange procedure (S420).

As such, after establishing the service flow, the mobile station 41 receives a downlink control channel including multicast resource allocation information from the base station 42 (S430), and receives multicast data from the base station 42 through the allocated resource (S440).

When a change of the service flow is required in the multicast service, the mobile station 41 and the base station 42 may perform a dynamic service change (DSC) procedure. That is, any one node of the mobile station 41 and the base station 42 transmits a DSC-REQ message, and the other node responds as a DSC-RSP message. In this case, the DSC-REQ message and the DSC-RSP message include a multicast parameter. The multicast parameter may include a current multicast group ID and a new multicast group ID, or current multicast group ID and FID and new multicast group ID and FID. The multicast parameter may further include a new multicast group zone ID.

When the multicast service is terminated, the mobile station 41 and the base station 42 may perform a dynamic service delete (DSD) procedure to delete the service flow. In this case, the multicast service of the multicast group may be terminated using the multicast group ID in the DSD procedure. The base station may terminate the multicast service using the multicast group zone ID in the DSD procedure. Any one node of the mobile station 41 and the base station 42 transmits a DSD-REQ message, and the other node responds as a DSD-RSP message.

As described above, according to an embodiment of the present invention, a mobile station and a base station can identify a supported multicast service through an exchange of a multicast service capability, and add, change or delete a service flow for the multicast service through a DSx (DSA, DSC, or DSD) procedure.

FIG. 5 is a flowchart of a multicast resource management method according to an embodiment of the present invention.

Referring to FIG. 5, a base station 52 persistently allocates a multicast resource to a multicast group for a multicast communication (S510), and transmits a downlink control channel including allocation information of multicast resource (S520). The downlink control channel may be a MAP information element (IE). For the multicast resource allocation, a new type of MAP IE may be defined. For example, the new type of MAP IE may be an HR-Multicast DL MAP IE (high reliability multicast downlink MAP IE) or an HR Multicast DL Assignment A-MAP IE that is a new type of A-MAP (advance MAP).

The base station 52 may fragment the multicast resource to use the limited multicast resource. That is, the base station 52 fragments the multicast resource, and transmits the multicast traffic through the fragmented multicast resources. In this case, the base station 52 includes a transmission indication (TI) to the downlink control channel, in order to indicate whether the multicast resource is fragmented (S520). The transmission indication can indicate that no fragmented traffic is transmitted or which of the fragmented traffics is transmitted, in accordance with its value.

A mobile station 51 identifies whether the received MAP IE is a MAP IE corresponding to the multicast group to which it belongs, based on the received MAP IE (S530). The mobile station 1 identifies the allocated multicast resource by the allocation information of multicast resource of the identified MAP IE, and identifies whether the fragmented traffic is transmitted through the allocated multicast resource or which of the fragmented traffics is transmitted when the fragmented traffic is transmitted (S540). Then, the mobile station 51 receives multicast traffic through the multicast resource (S550).

FIG. 6 shows an example of a multicast resource management method according to an embodiment of the present invention.

As shown in FIG. 6, the base station periodically (i.e., persistently) allocates the multicast resource at an interval of predetermined frames. The interval of predetermined frames corresponds to an allocation period. A plurality of frames, for example four frames may form one superframe, and one frame may include a plurality of subframes, for example eight subframes. In this case, the base station may transmit the MAP IE at a subframe to which the multicast resource is allocated.

The MAP IE includes multicast resource information allocated for the multicast communication, the allocation period, and a lifetime. The MAP IE further includes a transmission indication (TI). The lifetime indicates a period in which a persistent allocation is maintained, and the resource allocation information does not change until the lifetime expires. If the lifetime expires, the base station allocates a persistent resource for the multicast communication again or releases the previously allocated resource, and transmits the MAP IE including relevant information. The base station may transmit a next MAP IE at a frame whose frame number N_framesatisfies Equation 1, or may transmit the next MAP IE at a superframe whose superframe number N_superframesatisfies Equation 2.

N
_framemodulo L+1==0 (1)

N
_superframemodulo L+1==0 (2)

In Equations 1 and 2, L indicates the lifetime.

Accordingly, the mobile station can acquire information on the persistently allocated resource by only one decoding on the MAP IE such that a power loss that occurs when decoding the MAP IE can be reduced. Further, since the mobile station can know a period in which the MAP IE is transmitted or a period in which a multicast burst is transmitted in advance, the mobile station can efficiently perform a power saving when entering a power saving mode such as a sleep mode or an idle mode. Furthermore, the mobile station can know a time for decoding a new MAP IE by the lifetime included in the current MAP IE such that the mobile station can check a change of the persistently allocated resource.

In another embodiment, the base station may transmit a MAP IE including the same allocation information as previous allocation information before the lifetime expires. In this case, the base station may place a limit on a change or a release of the allocation information that it allows the change or release to be performed only when the lifetime expires. Accordingly, the base station can allow the mobile station to not unnecessarily receive and decode the resource information.

Table 1 shows an example of a transmission indication according to an embodiment of the present invention.

A base station can indicate whether additional traffic is transmitting before allocation period, by setting a value of the transmission indication as shown in Table 1.

When the multicast traffic is transmitted without being fragmented, the base station may set the value of the transmission indication to “00” to indicate that no additional transmission exists, that is, that no fragmented traffic is transmitted.

When the multicast traffic is fragmented into two fragmented traffics, the base station may set the value of the transmission indication of a downlink control channel corresponding to the first fragmented traffic to “01” and the value of the transmission indication of the downlink control channel corresponding to the second fragmented traffic to “10”. Accordingly, the base station can indicate that the multicast traffic has been fragmented and the downlink control channel corresponds to which of the fragmented traffics.

When the multicast traffic is fragmented into three or more fragmented traffics, the base station may set the value of the transmission indication of a downlink control channel corresponding to the first fragmented traffic to “01” and the value of the transmission indication of the downlink control channel corresponding to the last fragmented traffic to “11”. Further, the base station may set the value of the transmission indication of downlink control channels from the second to second last fragmented traffics to “10”. Accordingly, the base station can indicate that the multicast traffic has been fragmented and the downlink control channel corresponds to which of the fragmented traffics.

TABLE 1

Value
Description

0b00
no (no additional transmission)

0b01
first (first transmission)

0b10
continue (more transmission)

0b11
last (no more transmission)

The value of the transmission indication may change according to the fragmented condition of the multicast traffic each time the downlink control channel is transmitted. However, unless a lifetime expires, the downlink control channel excluding the value of the transmission indication does not change. If the lifetime expires, the downlink control channel may change or release the allocation.

An example of FIG. 6 shows that the multicast resource is persistently allocated with the allocation period of 2 and the lifetime of 6, the multicast resource is persistently allocated with the allocation period of 4 and the lifetime of 12, and then the allocated resource is released.

Further, the example of FIG. 6 shows that the multicast traffic is fragmented into three fragmented traffics when the allocation period is 2 and the lifetime is 6. The transmission indication TI of the MAP IE for the first fragmented traffic has a value of “01”, the transmission indication TI of the MAP IE for the second fragmented traffic has a value of “10”, and the transmission indication TI of the MAP IE for the last fragmented traffic has a value of “11”.

Furthermore, the example of FIG. 6 shows that the multicast traffic is not fragmented when the allocation period is 4 and the lifetime is 12. In this case, the transmission indication TI of the MAP IE has a value of “00”.

As such, according to an embodiment of the present invention, when the multicast traffic is fragmented by the limited resource, information about whether the multicast traffic is fragmented and information about which of the fragmented traffics is transmitted can be exactly provided to the mobile station together with the resource allocation information. Therefore, the limited resource can be efficiently used when the reliable multicast service is provided.

Next, various examples of a downlink control channel according to an embodiment of the present invention are described with reference to Table 2 to Table 6.

A MAP IE, for example an HR-Multicast DL MAP IE includes multicast resource information and subburst IE, and the subburst IE includes an allocation period, a lifetime, and a transmission indication. The subburst IE may be an HR_Multicast_DL_Subburst_IE.

The multicast resource information may be a predefined region ID (Region ID) or OFDMA symbol information and subchannel information. The OFDMA symbol information may include an OFDMA symbol offset and the number of OFDMA symbols, and the subchannel information may include a subchannel offset and the number of subchannels.

The HR-Multicast DL MAP IE may include an extended-2 DIUC (downlink interval usage code) and an extended-3 DIUC for indicating that the MAP IE is the HR-Multicast DL MAP IE, and may include a length of the MAP IE.

The subburst IE may further include a persistent flag, an allocation flag, allocation region information, or MCS (modulation coding scheme) level information. The persistent flag indicates whether the allocation is a persistent allocation, and the allocation flag indicates allocation of a resource or de-allocation of the resource. The allocation region information indicates an allocation region within a region allocated by the MAP IE, and may include a slot offset and slot duration. The MCS level information may be provided by the DIUC. The subburst IE may further include information on the multicast connection, for example a multicast group CID. The mobile station can identify the MAP corresponding to the multicast group to which it belongs by the multicast group CID.

The HR-Multicast DL MAP IE and the HR_Multicast_DL_Subburst_IE that are examples of the MAP IE and the subburst IE may be defined as in Table 2 and Table 3.

TABLE 2

Size

Syntax
(bit)
Notes

HR-Multicast DL MAP IE {

Extended-2 DIUC
4
HR Multicast DL Map IE( ) = 0xF

(Extended-3 DIUC)

Length
8
Length in bytes

Extended-3 DIUC
4
0x01

Region ID Indicator
1
0: not use Region_ID

1: use Region_ID

If (Region_ID use indicator == 0)

{

OFDMA symbol offset
8
Offset from the start of DL subframe

Subchannel offset
7

Number of OFDMA symbols
7

Number of subchannels
7

Rectangular subburst
1
Indicates subburst allocations are

Indication

time-first rectangular. The duration field

in each subburst IE specifies the

number of subchannels for each

rectangular allocation. This is only valid

for AMC allocations and all allocations

with dedicated pilots. When this field is

clear, subbursts shall be allocated in

frequency-first manner and the duration

field reverts to the default operation.

Reserved
2

} else

Region_ID
8
Index to the DL region defined in DL

region definition TLV in DCD

}

HR_Multicast_DL_Subburst_IE( )
variable
Table 3

Padding
variable
Padding to byte for the unspecified

portion of this IE (i.e. not including the

first two fields, “Extended-2 DIUC” and

“Length”); shall be set to 0.

}

TABLE 3

Size

Syntax
(bit)
Notes

HR_Multicast_DL_Subburst_IE( )

{

N subburst
4
Number of subbursts in the 2D

rectangular region is this field value plus

1.

Resource shifting indicator
1
0 = No Resource shifting

1 = Resource shifting

For(j=0;j<Number of

subbursts;j++){

Allocation Flag
1
1 = allocate

0 = de-allocate

Group Indicator
1
TDD mode: Reserved, set to 0.

Used for FDD/H-FDD case only; to

indicate the group assignment of the MS

(see 8.4.4.2 and 8.4.4.2.1)

0b0: Group #1

0b1: Group #2

If (Allocation Flag == 0) {

// deallocate

HR Multicast CID
16

If (Resource shifting

indicator == 1) {

Duration
variable
Duration in slots. OFDMA Frame

duration dependent

7 bits - 2.5 ms frame

8 bits - 5 ms frame

9 bits - 10 ms frame

10 bits - 20 ms frame

Slot Offset
variable
Indicates the start of this persistent

allocation in

OFDMA slots, with respect to the lowest

numbered

OFDM symbol and the lowest numbered

subchannel in the region.

OFDMA Frame duration dependent

7 bits - 2.5 ms frame

8 bits - 5 ms frame

9 bits - 10 ms frame

10 bits - 20 ms frame

}

} else if (Allocation Flag == 1)

// allocate

{

HR Multicast CID
16

Persistent Flag
1
0 = Non-persistent

1 = Persistent

if( Power boost per subburst ==

1 ){

Boosting
1
0b000: Normal (not boosted)

0b001: +6 dB

0b010: −6 dB

0b011: +9 dB

0b100: +3 dB

0b101: −3 dB

0b110: −9 dB

0b111: −12 dB;

Note that if the Persistent flag is set, the

boosting value applies to each instance

of the persistent allocation

}

Duration
variable
Duration in slots. OFDMA Frame

duration dependent

7 bits - 2.5 ms frame

8 bits - 5 ms frame

9 bits - 10 ms frame

10 bits - 20 ms frame

Slot Offset
variable
Indicates the start of this persistent

allocation in

OFDMA slots, with respect to the lowest

numbered

OFDM symbol and the lowest numbered

subchannel in the region.

OFDMA Frame duration dependent

7 bits - 2.5 ms frame

8 bits - 5 ms frame

9 bits - 10 ms frame

10 bits - 20 ms frame

If (Persistent Flag == 1) {

Allocation Period (ap)
5
Period of the persistent allocation is this

field

value plus 1 (unit is frame)

Lifetime(L)
4
Indicates the time to transmit the

information of this allocation and the

information except Transmission

Indication (TI) does not change until

lifetime expires. The next transmission of

information is at the frame whose frame

number, N_frame, satisfies the following

condition.

N_framemodulo L + 1 = 0

} else

Next allocation offset
5
5LSBs of frame number and it indicates

next allocation of the allocation of this

field

}

DIUC
4

Repetition Coding Indication
2
0b00: No Repetition coding

0b01: Repetition coding of 2 used

0b10: Repetition coding of 4 used

0b11: Repetition coding of 6 used

Transmission Indication (TI)
2
Indicates whether additional traffic is

transmitting before allocation period

0b00: no (no additional transmission)

0b01: first (first transmission)

0b10: continue (more transmission)

0b11: last (no more transmission)

}

}

Padding
variable
Padding to nibble; shall be set to 0.

}

The base station may add the above subburst IE (HR_Multicast_DL_Subburst_IE) to a hybrid automatic repeat request (HARQ) downlink MAP (HARQ DL MAP) for an HARQ resource allocation or a Persistent HARQ DL MAP for an HARQ persistent resource allocation, and use them for the multicast communication. For example, the HARQ DL MAP IE and the Persistent HARQ DL MAP IE may be defined as in Table 4 and Table 5.

TABLE 4

Size

Syntax
(bit)
Notes

Persistent_HARQ_DL_MAP_IE( )

{

Extended-2 DIUC
4
Persistent_HARQ_DL_MAP_IE = 0xD

Length
8
Length in bytes

RCID_Type
2
0b00: Normal CID

0b01: RCID11

0b10: RCID7

0b11: RCID3

For HR Multicast, RCID_Type is set to

0b00 and Normal CID is replaced by HR

Multicast CID

ACK Region Index
1
The index of the ACK region associated

with all subbursts (except HR multicast

DL burst) defined in this Persistent

HARQ DL MAP (FDD/H-FDD only)

while (data_remains){

Region ID use indicator
1
0: Region ID not used

1: Region ID used

Change Indicator
1
0: No change occurred

1: Change occurred

if (Region ID use indicator ==

0){

OFDMA Symbol offset
8

Subchannel offset
7

Number of OFDMA symbols
7

Number of subchannels
7

Rectangular subburst
1
Indicates subburst allocations are

indication

time-first rectangular. The duration field

in each subburst IE specifies the number

of subchannels for each rectangular

allocation. The slot offset field in each

subburst IE specifies the subchannel

offset from the first subchannel for each

rectangular allocation. When this field is

clear, subbursts shall be allocated in

frequency-first manner and the duration

field reverts to the default operation

}

else{

Region ID
8
Index to the DL region defined in DL

region definition

TLV in DCD

}

Power boost per subburst
1
Set to 1 to signal power boost per

subburst. This field

shall be set to 0 if Rectangular subburst

indication is set

to 0

if (Power boost per subburst ==

0){

Boosting
3
0b000: Normal (not boosted)

0b001: +6 dB

0b010: −6 dB

0b011: +9 dB

0b100: +3 dB

0b101: −3 dB

0b110: −9 dB

0b111: −12 dB

Note that if the Persistent flag is set, the

boosting value

applies to each allocation instance of the

persistent

allocation

}

Mode
4
Indicates the mode in this HARQ region

0b0000: Persistent DL Chase HARQ

0b0001: Persistent DL Incremental

redundancy HARQ

for CTC

0b0010: Persistent DL Incremental

redundancy HARQ

for Convolutional Code

0b0011: Persistent MIMO DL Chase

HARQ

0b0100: Persistent MIMO DL IR HARQ

0b0101: Persistent MIMO DL IR HARQ

for Convolutional

Code

0b0110: Persistent MIMO DL STC

HARQ

0b0111: HR Multicast DL subburst

0b1000 to 0b1111: Reserved

Subburst IE Length
8
Length, in nibbles, to indicate the size of

the subburst IE

in this HARQ mode. The MS may skip

DL HARQ

Subburst IE if it does not support the

HARQ mode.

However, the MS shall decode NACK

Channel field

from each DL HARQ Subburst IE to

determine the UL

ACK channel it shall use for its DL

HARQ burst

if( Mode == 0b0000){

Persistent DL Chase HARQ
variable

subburst IE

} elseif (Mode == 0b0001){

Persistent DL Incremental
variable

redundancy HARQ for CTC

subburst IE

} elseif (Mode == 0b0010){

Persistent DL Incremental
variable

redundancy HARQ for

Convolutional Code

} elseif (Mode == 0b0011){

Persistent MIMO DL Chase
variable

HARQ

} elseif (Mode == 0b0100){

Persistent MIMO DL IR
variable

HARQ

} elseif (Mode == 0b0101){

Persistent MIMO DL IR
variable

HARQ for Convolutional

Code

} elseif (Mode == 0b0110){

Persistent MIMO DL STC
variable

HARQ

} elseif (Mode == 0b0111){

HR Multicast DL subburst IE
variable
Table 3

}

}

Padding
variable
Padding to byte for the unspecified

portion of this IE

(i.e., not including the first two fields,

“Extended-2

DIUC” and “Length”); shall be set to 0.

}

TABLE 5

Size

Syntax
(bit)
Notes

HARQ_DL_MAP_IE( ) {

Extended-2 DIUC
4
HARQ_DL_MAP_IE( ) = 0x7

Length
8
Length in bytes

RCID_Type
2
0b00: Normal CID

0b01: RCID11

0b10: RCID7

0b11: RCID3

For HR Multicast, RCID_Type

is set to 0b00 and Normal CID

is replaced by HR Multicast

CID

ACK region index
1
The index of the ACK region

associated with all subbursts

(except HR multicast DL burst)

defined in this HARQ DL map

IE (FDD/H-FDD only).

0: first ACK region

1: second ACK region

This bit shall be set to 0 for

TDD mode.

Reserved
1

While (data remains) {

Boosting
3
0b000: Normal (not boosted)

0b001: +6 dB

0b010: −6 dB

0b011: +9 dB

0b100: +3 dB

0b101: −3 dB

0b110: −9 dB

0b111: −12 dB;

Region_ID use indicator
1 bit
0: not use Region_ID

1: use Region_ID

If (Region_ID use indicator == 0 ) {

OFDMA symbol offset
8
Offset from the start symbol of

DL subframe

Subchannel offset
7

Number of OFDMA symbols
7

Number of subchannels
7

Rectangular subburst Indication
1
Indicates subburst allocations

are time-first rectangular. The

duration field in each subburst

IE specifies the number of

subchannels for each

rectangular allocation. This is

only valid for AMC allocations

and all allocations with

dedicated pilots. When this

field is clear, subbursts shall

be allocated in frequency-first

manner and the duration field

reverts to the default

operation.

Reserved
2

} else {

Region_ID
8
Index to the DL region defined

in DL region definition TLV in

DCD

}

Mode
4
Indicates the mode of this

HARQ region:

0b0000: Chase HARQ

0b0001: Incremental

redundancy HARQ for CTC

0b0010: Incremental

redundancy HARQ for

Convolutional Code 0b0011:

MIMO Chase HARQ

0b0100: MIMO IR HARQ

0b0101: MIMO IR HARQ for

Convolutional Code

0b0110: MIMO STC HARQ

0b0111: HR Multicast DL

subburst

0b1000-0b1111: Reserved

Subburst IE Length
8
Length, in nibbles, to indicate

the size of the sub-burst IE in

this HARQ mode. The MS may

skip DL HARQ Subburst IE if it

does not support the HARQ

mode. However, the MS shall

decode N ACK Channel field

from each DL HARQ Subburst

IE to determine the UL ACK

channel it shall use for its DL

HARQ burst.

If (Mode == 0b0000) {

DL_HARQ_Chase_subburst_IE( )
variable

} else if (Mode == 0b0001) {

DL_HARQ_IR_CTC_subburst_IE( )
variable

} else if (Mode == 0b0010) {

DL_HARQ_IR_CC_subburst_IE( )
variable

} else if (Mode == 0b0011) {

MIMO_DL_Chase_HARQ_subburst_IE( )
variable

} else if (Mode == 0b0100) {

MIMO_DL_IR_HARQ_subburst_IE ( )
variable

} else if (Mode == 0b0101) {

MIMO_DL_IR_HARQ_for_CC_—subburst_IE( )
variable

} else if (Mode == 0b0110) {

MIMO_DL_STC_HARQ_subburst_IE( )
variable

} elseif (Mode == 0b0111){

HR Multicast DL subburst IE
variable
Table 3

}

}

Padding
variable
Padding to byte for the

unspecified portion of this IE,

i.e., not including the first two

fields, “Extended-2 DIUC” and

“Length”; shall be set to 0

}

Since fields that are not described in Table 2 to Table 5 are defined in, for example, IEEE Std 802.16-2012, descriptions for the fields are omitted.

Next, multicast resource allocation information according to another embodiment of the present invention will be described with reference to Table 6.

A base station may generate a multicast allocation A-MAP IE for allocating a multicast resource using an A-MAP, and the multicast allocation A-MAP IE may be for example an HR-Multicast DL Assignment A-MAP IE.

The multicast allocation A-MAP IE includes an allocation period, a lifetime, a transmission indication, and multicast allocation information as described above. The multicast allocation information may include a resource index indicating a location and a size of the multicast resource. The multicast allocation information may further include information (Isizeoffset) used to compute a burst size index and an indicator (long TTI indicator) indicating the number of subframes spanned by the allocated resource.

The multicast allocation A-MAP IE may inform whether the A-MAP IE is allocation of a resource or de-allocation of the resource by a value of the allocation period, without using a flag for indicating the allocation or the de-allocation. For example, when the allocation period has a value of “00”, the A-MAP IE may indicate the de-allocation.

The base station may generate 16-bit cyclic redundancy check (CRC) based on the randomized sequence of information bits of the multicast allocation A-MAP IE. Further, the base station may mask the 16-bit CRC by a CRC mask including a multicast group ID, and attach the masked CRC to the multicast allocation A-MAP IE. The terminal can identify the multicast allocation A-MAP IE using the CRC mask including the multicast group ID to which it belongs. That is, the mobile station can identify the multicast allocation A-MAP IE corresponding to the multicast group to which it belongs using the CRC mask.

The HR-Multicast DL Assignment A-MAP IE that is an example of the multicast allocation A-MAP IE may be defined as in Table 6.

TABLE 6

Size

Field
(bits)
Value/Description

HR-Multicast_DL_Assignment_A-MAP_IE( )

{

A-MAP IE Type
4
HR-Multicast DL Assignment A-MAP

IE

Allocation period
2
Period of persistent allocation of

multicast resource.

If (Allocation Period == 0b00), it

indicates the deallocation of

persistent resource.

0b00: deallocation

0b01: 2 frames

0b10: 4 frames

0b11: 6 frames

If (Allocation Period == 0b00) {

Resource Index
11
5 MHz: 0 in first 2 MSB bits + 9 bits

for resource index

10 MHz: 11 bits for resource index

20 MHz: 11 bits for resource index

Resource index includes location and

allocation size.

Long TTI Indicator
1
Indicates number for AAI subframes

spanned by the allocated resource.

0b0: 1 AAI subframe (default TTI)

0b1: 4 DL AAI subframe for FDD or

all DL AAI subframes for TDD (long

TTI)

Reserved
22

} else if(Allocation Period !=

0b00) {

Isizeoffset
5
Offset used to compute burst size

index

MEF
2
MIMO encoder format

0b00: SFBC

0b01: Vertical encoding

0b10: Multi-layer encoding

0b11: CDR

If (MEF ==0b01) {

Parameter for vertical encoding

M_t
3
Number of streams in transmission

M_t<= N_t

N_t: Number of transmit antennas at

the HR-BS

0b000: 1 stream

0b001: 2streams

0b010: 3streams

0b011: 4streams

0b100: 5streams

0b101: 6streams

0b110: 7streams

0b111: 8streams

Reserved
1

} else if (MEF == 0b10) {

Parameters for multi-layer encoding

Si
4
Index to identify the combination of

the number of streams and the

allocated pilot stream index in a

transmission with MU-MIMO, and the

modulation constellation of paired

user in the case of 2 stream

transmission

0b0000: 2 streams with PSI = stream1

and other modulation = QPSK

0b0001: 2 streams with PSI = stream1

and other modulation = 16QAM

0b0010: 2 streams with PSI = stream1

and other modulation = 64QAM

0b0011: 2 streams with PSI = stream1

and other modulation information not

available

0b0100: 2 streams with PSI = stream2

and other modulation = QPSK

0b0101: 2 streams with PSI = stream2

and other modulation = 16QAM

0b0110: 2 streams with PSI = stream2

and other modulation = 64QAM

0b0111: 2 streams with PSI = stream2

and other modulation information not

available

0b1000: 3 streams with PSI = stream1

0b1001: 3 streams with PSI = stream2

0b1010: 3 streams with PSI = stream3

0b1011: 4 streams with PSI = stream1

0b1100: 4 streams with PSI = stream2

0b1101: 4 streams with PSI = stream3

0b1110: 4 streams with PSI = stream4

0b1111: n/a

}

Resource Index
11
5 MHz: 0 in first 2 MSB bits + 9 bits

for resource index

10 MHz: 11 bits for resource index

20 MHz: 11 bits for resource index

Resource index includes location and

allocation size.

Long TTI Indicator
1
Indicates number for AAI subframes

spanned by the allocated resource.

0b0: 1 AAI subframe (default TTI)

0b1: 4 DL AAI subframe for FDD or

all DL AAI subframes for TDD (long

TTI)

Lifetime(L)
4
Indicates the time to transmit next

HR-Multicast DL Assignment A-MAP

and the information excluding

Transmission Indication (TI) of this

HR-Multicast DL Assignment A-MAP

does not change during the allocation

duration.

The next HR-Multicast DL

Assignment A-MAP is at the

superframe whose superframe

number, N_superframe, satisfies the

following condition.

N_superframemodulo L + 1 = 0

Transmission Indication (TI)
2
Indicates whether additional traffic is

transmitting before allocation period

0b00: no (no additional transmission)

0b01: first (first transmission)

0b10: continue (more transmission)

0b11: last (no more transmission)

Reserved
5

}

}

Since fields that are not described in Table 6 are defined in, for example, IEEE Std 802.16.1-2012, descriptions for the fields are omitted.

Next, a multicast resource management apparatus for performing a multicast resource management apparatus according to an embodiment of the present invention is described with reference to FIG. 7 and FIG. 8.

FIG. 7 is a block diagram of a multicast resource management apparatus according to an embodiment of the present invention.

Referring to FIG. 7, a multicast resource management apparatus 700 includes a resource manager 710 and a transmitter 720.

The resource manager 710 allocates a multicast resource to a multicast group, and generates a MAP IE including allocation information of the multicast resource, an allocation period, a lifetime, and a transmission indication. The transmitter 720 transmits the MAP IE to the multicast group.

The multicast resource management apparatus 700 may be included in a base station or may be the base station itself.

FIG. 8 is a block diagram of a multicast resource management apparatus according to another embodiment of the present invention.

Referring to FIG. 8, a multicast resource management apparatus 800 includes a receiver 810 and a controller 820.

The receiver 810 receives a MAP IE from a base station. The MAP IE includes allocation information of the multicast resource allocated to a multicast group, an allocation period, a lifetime, and a transmission indication. The controller 820 identifies whether the received MAP IE corresponds to the multicast group to which it belongs, by a multicast group IE or a CRC mask. The controller 820 identifies whether the multicast resource is fragmented by using the identified MAP IE.

The multicast resource management apparatus 800 may be included in a mobile station or may be the mobile station itself.

At least some functions of a multicast resource management method or apparatus according to an embodiment of the present invention may be embodied by hardware or software combined with the hardware. For example, a processor that is embodied by a central processing unit (CPU), a chipset, or a microprocessor, etc. may perform a function of a resource manager 710 or a controller 820, and a transceiver may perform a function of a transmitter 720 or a receiver 810.

While this invention has been described in connection with what is presently considered to be practical embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Number	Date	Country	Kind
10-2012-0022939	Mar 2012	KR	national
10-2013-0023128	Mar 2013	KR	national

METHOD AND APPARATUS FOR MANAGING MULTICAST RESOURCE

Information

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Date Filed

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Inventors

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CPC

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Abstract

Description

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Priority Claims (2)