Patent Application
20100260088
The present invention relates to a communication system and, in particular, to a system and method for providing a fast Multicast and Broadcast service (MBS) without waste of resources in a multi-hop relay communication system.
Many researches have been done for providing subscribers with communication services having various Quality of Service (QoS) requirements. Recently, Broadband Wireless Access (BWA) communication systems, as next generation communication systems, are developed in focusing on the mobility and guaranteed QoS without compromising high data rate.
The BWA communication systems are characterized by supporting high speed multimedia, e.g. MBS, as well as conventional voice and packet data services. Typically, communication system for providing MBS includes a transmitter, i.e. Base Station (BS), for broadcast/multicast information and a plurality of receivers, i.e. Mobile Stations (MS) for receiving the information broadcasted/multicasted from the BS.
The communication system for providing MBS divides its broadcast service area into multiple service zones and allocates at least one transmitter per service section such that the MSs located in a specific service zone receive the MBS data broadcasted/multicasted from the transmitter of the service zone. The communications system for providing MBS can be configured such that one transmitter controls other transmitters that are responsible for their individual service zones to provide the MBS data simultaneously.
In the meantime, the BWA communication system tends to be implemented with multi-hop relaying architecture with an increased number of BSs or Relay Stations (RS) that are configured to establish relay paths to the MSs for improving data rate and entire system throughput in a service zone.
For the multi-hop relay communication system, the BSs, RSs, and MSs within the same MBS zone are synchronized and then the MBS data are transmitted, and the BSs should be synchronized in network level.
In a case that the multi-hop relay communication system provides in a multi-BS access scheme for the MBS, all the BSs within the same MBS zone broadcast the MBS data at an identical position of a synchronized frame unlike the single-BS access scheme in which a single BS broadcasts the MBS data.
In a case that there is only one RS connection with the BS, i.e. a maximum hop count of the path between the BS and MS is 2, the RS reports its processing delay in unit of frame to the BS as a capability parameter in a basic capability request message. When an MBS data transmission is necessary, the BS first transmit the MBS data over a relay downlink as a pre-transmission, and then after processing delay, the BS and RS synchronously transmit the MBS data over an access link.
In a case that there are multiple RSs connecting with the BS in the MBS zone at various hop counts from the BS and/or with different processing delays, each RS report its processing delay in unit of frame to the BS as a capability parameter in a basic capability request message, and the BS determines the maximum cumulative delay of all RSs in the MBS zone based on their position in the tree and their individual processing delays. The BS then calculates each RSs cumulative delay and calculates a required waiting time for each RS based on the value of the maximum cumulative delay, and notifies each RS of its waiting time via a basic capability response message.
If the BS detects that the waiting time has changed for a specific RS, it may transmits an unsolicited response message to the RS to update its waiting time. When an MBS data transmission is necessary, the BS transmits the MBS data over the relay downlink as a pre-transmission maximum cumulative delay frames before transmitting the MBS data over the access link, and each RS in the MBS zone transmits the received MBS data over its relay downlink. Finally, once the BS has waited the maximum accumulative delay frames and each RS has waited its specified waiting time, the BS and RSs synchronously transmit the MBS data over the access links.
Meanwhile, when the multi-hop relay communication system transmits MBS data in multi-BS access scheme, the MBS data is transmitted to the RSs in unicast scheme and each MS can receive the MBS data from multiple MSs located in the same MBS zone so as to achieve macro diversity gain. In this case, since the MS receives the MBS data from multiple BSs, i.e. the MBS data is transmitted in multi-BS access scheme, the MBS data is relayed via all the RSs, despite there is no need to transmit the MBS data to all the RSs.
In other words, the conventional multi-hop relay communication system transmits such that the MBS data transmitted from a BS is relayed via RSs that are necessary the MBS data transmission and that are unnecessary the MBS data transmission to a specific MS, whereby the system resource are allocated the RSs that are unnecessary the MBS data transmission, resulting in waste of resource. Also, the conventional multi-hop relay communication system has a drawback in that, since the MBS data transmission is performed in consideration of the cumulative delays and required waiting times of the respective RSs, cumulative transmission and reception delays occur.
In order to overcome the above problems of the prior art, the present invention provides a system and method for providing an MBS in a communication system.
Also, the present invention provides a system and method for providing an MBS in a multi-hop relay communication system.
Also, the present invention provides a system and method for providing an MBS in a multi-hop relay communication system including a plurality of relay stations by using a multi-BS access scheme.
According to one aspect of the present invention, there is provided a method for providing a multicast and broadcast service (MBS) at a base station in a wireless communication system including base station, mobile station providing the MBS, and a plurality of relay stations for providing relay path between the base station and the mobile station. The method includes receiving Relay Station's Basic Capability Negotiation Request (SBC-REQ) messages transmitted from the relay stations; checking a capability information included in the SBC-REQ messages, and allocating resources to the mobile station and a relay station among the relay stations based on the capability information; and providing the MBS to the mobile stations using the allocated resources.
According to another aspect of the present invention, there is provided a method for providing multicast and broadcast service (MBS) in a wireless communication system including base station, mobile station providing the MBS, and a plurality of relay stations for providing relay path between the base station and the mobile station. The method includes transmitting, at a relay station, a Relay Station's Basic Capability Negotiation Request (SBC-REQ) message to the base station; being allocated resources form the base station, at the relay station needed MBS data transmission in response to the SBC-REQ message; and providing, at the relay station, the MBS received from the base station to the mobile station using the allocated resources.
According to further another aspect of the present invention, there is provided a method for managing relay stations in a multi-hop relay network supporting a multicast and broadcast service (MBS) in a multi-base station access scheme. The method includes transmitting to a base station, at a relay station, a message including a capability information indicating whether MBS data transmission is necessary in accordance with preset status of the relay station; and transmitting, at the relay station, a MAP information received from the base station to mobile station or another relay station in accordance with the message, when the message includes the capability information indicating which the MBS data transmission is unnecessary.
According to yet another aspect of the present invention, there is provided a system for providing a multicast and broadcast service (MBS) in a wireless communication system. The system includes a base station; a mobile station supporting the MBS; and a plurality of relay stations providing relay links from the base station to the mobile station, wherein the base station receives Relay Station's Basic Capability Negotiation Request (SBC-REQ) messages from the relay stations, checks capability information included in the SBC-REQ message, allocates resources to the mobile station and a relay station among the relay stations based on the capability information; and the relay station provides the MBS provided from the base station to the mobile station using the allocated resources.
According to still another aspect of the present invention, there is provided a system for providing a multicast and broadcast service (MBS) in a wireless communication system. The system includes a base station; a mobile station supporting the MBS; and a plurality of relay stations providing relay links from the base station to the mobile station, wherein the relay stations each transmit Relay Station's Basic Capability Negotiation Request (SBC-REQ) messages to the base station, a relay station is allocated resources by the base station, wherein the relay station needed MBS data transmission among the relay stations based on the SBC-REQ messages, the mobile station is provided MBS from the base station via relay path providing the relay station allocated resources.
The MBS provision method and system of the present invention allocates resources to relay stations in consideration of their capabilities in a communication system, thereby preventing waste of resources and reducing transmission and reception delay, resulting in fast MBS. Also, the MBS provision method and system of the present invention allocates resources to only the relay stations that are necessary to transmit MBS data so as to establish optimal relay links, thereby preventing waste of resources and reducing transmission and reception delays at the base and mobile stations.
The above and other aspects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which:
Preferred embodiments of the present invention will now be described in detail with reference to the annexed drawings. In the drawings, the same or similar elements are denoted by the same reference numerals even though they are depicted in different drawings. In the following description, a detailed description of known functions and configurations incorporated herein has been omitted for clarity and conciseness.
The present invention proposes a system and method for providing Multicast and Broadcast service (MBS) in a communication system, e.g. Broadband Wireless Access (BWA) communication system based on the Institute of Electrical and Electronics Engineers (IEEE) 802.16 standards. In order to help understanding the present invention, the present invention is described with an exemplary IEEE 802.16 standards-base communication system using Orthogonal Frequency Division Multiplexing (OFMD)/Orthogonal Frequency Division Multiple Access (OFDMA), however, the present invention is not limited thereto, but can be applied to other communication systems based on the evolutions of IEEE 802.16 standards to be rectified in the future.
Also, the present invention proposes a system and method for providing the MBS in a wireless communication system comprising a transmitter, e.g. Base Station (BS) for controlling a service zone of a wireless communication system and receivers provided the MBS from the BS, e.g. Mobile stations (MSs) having fixity/mobility. In the following description, the MBS provision system and method of the present invention is described with a communication system for providing MBS in which each MS is provided by at least one BS in a multi-BS access scheme.
Unlike the single-BS access scheme in which an MS is connected to a BS providing MBS, the multi-BS access scheme allows an MS to receive MBS data transmitted from multiple BSs, within the same MBS zone, and transmitted at an identical position of a synchronized frame, thereby achieving macro diversity gain. At this time, the MS identifies the MBS zone with reference to an MBS zone identifier (ID). The MBS zone is an area in which the same MBS flow is served with a Connection Identifier (CID) or a Security Association (SA), i.e. which can be provided the MBS. The MBS zone information is transmitted to the MSs via a Downlink Channel Descriptor (DCD) message. That is, the MBS zone can be defined as a group of BSs using the same CIDs and same SAs for providing MBS, i.e. for transmitting the same MBS data.
Also, in a multi-hop relay communication system including a plurality of Relay Stations (RSs) proving multi-hop relay paths according to the present invention, the system allocates resources to the RSs in consideration of their capabilities and finds optimal relay paths between the BSs and MSs, thereby improving service quality without waste of resources. In the following description, RSs transmits messages including their capabilities to the BS such that the BS checks the capabilities of the RSs and schedules MBS data transmission for providing the MSs with the MBS via RSs based on the capabilities.
In a case that multiple relay paths with plural RSs at various hop counts are established between the BS and MS, the BS receives processing delays of the RSs in unit of frame as a capability parameter and determines a maximum cumulative delay of all RSs in the MBS zone based on their positions in the tree and their individual processing delays. The BS then calculates the required waiting time for each RS based on the value of maximum cumulative delay and each RS's cumulative delay and notifies each RS of its waiting time via a response message. If the BS detects that the waiting time has changed for a particular RS, it may transmit an unsolicited response message to that RS to update its waiting time.
When an MBS data transmission is necessary, the BS transmits the MBS data over the relay downlink as a pre-transmission maximum delay frames before transmitting the MBS data over the access link. The RSs in the MBS zone transmit the MBS data received over the relay downlink. Finally, once the BS has waited maximum delay frames and each RS has waited its specified time, the BS and RSs synchronously transmit the MBS data over the access links.
In the case that multiple RSs providing relay links for paths between the BS and MS exist, i.e. multiple RSs establish relay links at various hop counts from the BS to the MS, the communication system according to an embodiment of the present invention determines the MBS data transmission time to the MS based on the maximum cumulative delay and each RS's cumulative delay and waiting time, and schedules MBS data transmission based on the RS's capabilities, and provides MBS to the MS. Particularly, when the RSs that are unnecessary for the MBS data transmission exist, e.g. the MS is not need to receive the MBS data via RSs but from more than one BS, the BS checks the information on the RSs (i.e. the information on whether the MBS data transmission of the RSs are necessary), allocates resources to the only the necessary RSs that are needed to participate in the MBS data transmission, and transmits the MBS data via the qualified RSs using the allocated resources in consideration of the cumulative delays and required waiting times of the qualified RSs, thereby reducing the transmission and reception delay and preventing waste of resources, resulting in fast MBS.
That is, in the communication system according to an embodiment of the present invention, the BS determines whether to provide the MBS via relay links, i.e. the BS perform resource scheduling in consideration of necessity of the RSs, and then transmits the MBS data to the MS. At this time, the BS allocates the resources to the RSs necessary for establishing relay links and transmits the MBS data to the MS via the necessary RSs. This prevents the resources from being allocated to the RSs unnecessary for the MBS data transmission, resulting in prevention waste of resource. Also, since the resources are allocated only for the necessary RSs, the MBS data is not relayed via unnecessary relay links but via optimal relay links, thereby reducing waiting time of the MS and providing fast MBS.
The RSs are classified into non-MBS RSs that are excluded for the MBS data transmission, static multi-BS MBS RSs that supports MBS data transmission in the static multi-BS MBS mode, and dynamic multi-BS MBS RSs that support the MBS data transmission in the dynamic multi-BS MBS mode. The RS that needs the MBS data transmission in the static multi-BS MBS mode supports the MBS data transmission regardless of the existence of destination MS such that the static multi-BS MBS RS is allocated the resource for establishing relay links and relays the MBS data using the resource. The RS that needs the MBS data transmission in the dynamic multi-BS MBS mode supports the MBS data transmission only when at least one destination MS exists such that the dynamic multi-BS MBS RS is allocated resource, when the destination MS is detected, and relays the MBS data using the resource. If the MS has stopped receiving the MBS data or handed over to another cell in the middle of receiving the MBS data from the RS transmitting MBS data in the dynamic multi-BS MBS mode, the resource allocated to the dynamic multi-BS MBS RS is released.
Whether the MBS data transmission of each RS is necessary, i.e. the RS configuration associated with the MBS data transmission, is determined based on the position of the RS within the MBS zone in the communication environment of the network at the initial system configuration stage, particularly, the MBS zone coverage established by the BS, macro diversity, and the positions of the RSs for supporting the MBS data transmission to the MS. For example, the RSs located at the boundary region of the MBS zone for expanding the MBS zone coverage, the RSs for serving the MSs located in the shade areas and coverage hole such as inside of and between buildings, the RSs deployed for serving the MSs inside buildings and mobile vehicles and temporarily expanding the MBS zone coverage, and the RSs deployed for increasing macro diversity are determined as the RSs that are needed to transmit MBS data, i.e. static multi-BS MBS RSs and/or dynamic multi-BS MBS RSs, and other RSs are determined as the RSs that are not need to transmit MBS data, i.e. non-MBS RSs. All the types of RSs report their capability information to the BS.
Each RS of which the MBS data transmission mode is determined in the initial network configuration transmits a Relay Station's Basic Capability Negotiation Request (SBC-REQ) message including its capability information to the BS or RS in initial connection procedure, or the BS transmits a Relay Station's Basic Capability Negotiation Response (SBC-RSP) message including the capability of each RS that is determined in the initial network configuration to the corresponding RS. The SBC-REQ and SBC-RSP messages are Media Access Control (MAC) messages that are exchanged between the BS and RSs through the capability negotiation process in the network entry procedure. The SBC-REQ and SBC-RSP messages include the RS capability information such as available modulation and coding scheme information and information indicating MBS data transmission necessity and the MBS data transmission mode for the RS. Here, MBS indication information includes Type Length Value (TLV) of the SBC-REQ/SBC-RSP message as shown in table 1.
Table 1 shows an SBC-REQ/SBC-RSP message including information indicating the MBS data transmission necessary and the MBS data transmission mode. The SBC-REQ/SBC-RSP message includes an MBS data TLV of TBA (To Be Assigned) indicating MBS data transmission necessity of the RS in the RS's capability information. The first bit (#0) of the TLV, i.e. the Least Significant Bit (LSB) indicates that the RS transmitted the SBC-REQ/SBC-RSP message is necessary for transmitting MBS data in static multi-BS MBS mode, i.e. the RS can transmit the MBS data regardless of the existence of a destination MS. This bit can be checked as the information requesting MBS data transmission. The second bit (#1) of the TLV indicates that the RS transmitted the SBC-REQ/SBC-RSP message is necessary for transmitting MBS data in dynamic multi-BS MBS mode, i.e. the RS can transmit the MBS data when the destination MS exists. This bit can be checked as the information selectively requesting MBS data transmission.
In more detail, the one-byte long TLV of which the first and second bits (#0 and #1) are set to ‘0’ indicates the RS transmitted the SBC-REQ/SBC-RSP message is unnecessary for the MBS data transmission but the MBS-MAP Information Element (MBS-MAP IE), whereby the BS does not allocate resource to the RS for MBS data transmission.
The TLV of which the first bit (#0) is set to ‘1’ and the second bit (#1) is set to ‘0’ indicates that the RS transmitted the SBC-REQ/SBC-RSP message is necessary for the MBS data transmission in the static multi-BS MBS mode such that the RS can transmit the MBS data regardless of the existence of the destination MS. Accordingly, the BS allocates resources the BS such that the BS can always receive and transmit the MBS data and MAP messages including the MBS-MAP IEs.
In the meantime, the TLV of which the first bit (#0) is set to ‘0’ and the second bit (#1) is set to ‘1’ indicates that the RS transmitted the SBC-REQ/SBC-RSP message is necessary for the MBS data transmission in the dynamic multi-BS MBS mode such that the RS can selectively transmit the MBS data depending on the communication environment and whether the destination exists. For example, if an MS receiving the MBS data via the RS transmitting MBS data in the dynamic multi-BS MBS mode has stop receiving the MBS data or handed over to another cell such that no destination cell exists, the RS transmits a Dynamic Service Deletion Request (DSD-REQ) message to the BS and stops transmitting the MBS data. Meanwhile, there is at least one other destination MS entry is detected, the RS Dynamic Service Addition Request (DSA-REQ) message such that the RS is allocated resource to transmit the MBS data to the MS. The BS allocates the resource to the RS transmitting MBS data in the dynamic multi-BS mode and transmitted the SBC-REQ/SBC-RSP message and, if receiving the DSD-REQ message including the MBS data transmission termination information, releases the resource allocated for the MBS data transmission but maintains the resources for transmitting the MAP message including the MBS-MAP IEs. When there is at least one destination MS linked to the RS and the DSA-REQ message is received from the RS, the BS allocates the resource for the MBS data transmission to the RS such that the RS can transmit the MBS data and MAP messages including the MBS-MAP IEs.
Here the RS transmitting MBS data in the static multi-BS MBS mode can be of being temporarily installed for expanding MBS zone coverage in accordance with variation of the communication environment or installed in a tunnel or subway for supporting handover of MSs; and the RS transmitting MBS data in the dynamic multi-BS MBS mode can be of being installed at the boundary of the MBS zone for expanding the MBS zone coverage, installed in a shade area or a coverage hole for enhancing the MBS to the MSs inside a building and between buildings, installed inside buildings and mobile vehicle for expanding the MBS coverage, and installed for increasing macro diversity gain.
The communication system according to an embodiment of the present invention allocates resources to the RSs in consideration of their capabilities, i.e. MBS data transmission necessity and the MBS data transmission mode, whereby the resources are allocated to only the RSs that are currently necessary for MBS data transmission, resulting in prevention waste of resource. Since the RSs that are currently not necessary for MBS data transmission are not allocated the resources, they cannot activate relay links for MBS data transmission, whereby the network can provide optimal relay links of a path between the BS and MS, resulting in reduction of transmission delay of the BS and reception delay of the MS. Although the MBS provision system and method of the present invention is described with an exemplary case in which each RS transmits an SBC-REQ message carrying its capability to the BS in order to simplify the explanation, the present invention is not limited thereto. For example, the MBS provision system and method of the present invention can be implemented with a case in which the BS transmits an SBC-RSP message carrying the capability information of each RS within the MBS zone. Now, a structure and functions of a communication system for providing MBS are described in more detail with reference to
Referring to
As aforementioned, each of the RSs 140, 150, and 160 transmits an SBC-REQ message including its capability to the BS1110 in initial access procedure, and the BS1110 received the SBC-REQ message checks the MBS data transmission mode of the RS transmitted the SBC-REQ message with reference to the TLV. From the checking results, the BS1110 comes to know that the RS1140 is necessary the MBS data transmission in the static multi-BS MBS mode, the RS2150 is necessary the MBS data transmission in the dynamic multi-BS MBS mode, and the RS3160 is unnecessary the MBS data transmission in non-MBS mode.
After checking the MBS data transmission of the RSs 140, 150, and 160, the BS1110 performs scheduling to allocate resources to the RSs 140, 150, and 160, i.e. generating a downlink (DL) subframe (not shown) for transmitting MBS data. The DL subframe includes a preamble zone, a Frame Control Header (FCH) zone, a MAP zone, and a burst zone.
The preamble zone includes synchronization information for acquiring synchronization among the BS1110, MS 130, and RSs 140, 150, and 160, i.e. preamble sequence is transmitted. The FCH zone includes basic information on the subchannels, ranging, modulation scheme, and the like. The MAP zone is used to transmit MAP message including MAP information, i.e. includes a downlink (DL)-MAP zone and an uplink (UL)-MAP zone. The DL-MAP zone carries a DL-MAP message including DL-MAP information, and the UL-MAP zone carries a UL-MAP message including UL-MAP information. The DL-MAP message includes MAP information having MBS-MAP Information Elements (MBS-MAP IEs), i.e. DL-MAP information, and the MBS-MAP IEs include information on burst regions allocated for transmitting the MBS data.
As described above, the BS1110 checks the capacities of the RSs 140, 150, and 160 from the SBC-REQ messages, i.e. the BS1110 checks the TLVs of the SBC-REQ messages transmitted from the RSs 140, 150, and 160 and recognizes the RS1140 transmitting MBS data in the static multi-BS MBS mode (i.e. RS transmitting MAP information having MBS-MAP IEs and MBS data as RS always necessary for the MBS data transmission), the RS2150 transmitting MBS data in the dynamic multi-BS MBS mode (i.e. RS transmitting MAP information having MBS-MAP IEs and MBS data as RS necessary for the MBS data transmission according to the communication environment), and the RS3160 non-transmitting MBS data in the non-MBS mode (i.e. RS unnecessary the MBS data transmission).
After checking the capabilities of the RSs, the BS1110 performs scheduling on the basis of the RSs' capabilities to allocate the resources to the RS1140 and RSs2150 for transmitting MBS data but not to the RS3160. That is, the BS1110 allocates a burst region for transmitting the MBS data from the BS1100 to the MS 130, a burst region for transmitting the MBS data from the RS1140 to the MS 130, and a burst region for transmitting the MBS data from the RS2150 to the MS 130. Also, the BS1110 allocates a burst region for transmitting the MBS data from the BS1110 to the RS1140 and a burst region for transmitting the MBS data from the BS1110 to the RS2150.
The MBS data is transmitted using the burst regions such that the MS 130 receives the MBS data from the respective BS1110, RS1140, and RS2150. The MS 130 also receives the MAP message including the MBS-MAP IEs via the respective BS1110, RS1140, RS2150, and RS3160.
As described above, if the MS 130 receiving the MBS data from the BS1110 hands over to another cell or stops receiving the MBS data, the RS2150 transmitting MBS data in the dynamic multi-BS MBS mode transmits the BS1110 a DSD-REQ message including MBS data transmission termination information. Upon receipt of the DSD-REQ message, the BS1110 releases the resource allocated to the BS2150 for relaying the MBS data. At this time, the BS1110 determines that the RS2150 is unnecessary for relaying the MBS data to the MS 130, so as not to allocate the burst region for the RS2150. In this case, the RS2150 can relay the MAP message including the MBS-MAP IEs like the RS3160. If receiving a request for the MBS from the MS 130, the RS2150 transmits a DSA-REQ message to the BS1110. Upon receipt of the DSA-REQ message, the BS1110 allocates a burst region for the RS2150 to relay the MBS data.
In this manner, the BS1110 receives the SBC-REQ messages including the capability information from the RSs 140, 150, and 160 and performs resource scheduling based on the capability information of the SBC-REQ messages. That is, the BS1110 checks the MBS necessities of the RSs 140, 150, and 160 with reference to the TLVs of the SBC-REQ messages, allocates resources to the RS1140 and RS2150 but not the RS3160 based on the checking results, thereby preventing the resource from being allocated to the MBS-unnecessary RS. In this case, the RS3160 non-transmitting MBS data in the non-MBS mode can relay only the MAP message including the MBS-MAP IEs, whereby the cumulative delay and required waiting time of the RS3 is not needed to be considered when transmitting the MBS data. This reduces the MBS data transmission delay of the BS1110 and the MBS data reception delay of the MS 130, resulting in fast MBS.
Although the MBS provision method is described with an exemplary case in that the BS1110 allocates resources with reference to the SBC-REQ messages transmitted from the RSs 140, 150, and 160 for providing the MBS to the MS 130, the BS2120 can receive the SBC-REQ messages and allocate resources for providing the MBS to the MS 130 in the same manner as the BS1110. That is, the MS 130 can be provided from the BS1110 and BS2120 in the multi-BS MBS mode. The operations of a BS in the communication system according to an embodiment of the present invention are described hereinafter in more detail with reference to
Referring to
In more detail, the BS checks the first and second bits (#0 and #1) in the TLV of the SBC-REQ message and determines the RS transmitted the SBC-REQ message including the TLV of which both the first and second bits are set to ‘0’ as RS non-transmitting MBS data in a non-MBS, the RS transmitted the SBC-REQ message including the TLV of which the first bit is set to ‘1’ and the second bit is set to ‘0’ as RS transmitting MBS data in a static multi-BS MBS mode, and the RS transmitted the SBC-REQ message including the TLV of which the first bit is set to ‘0’ and the second bit is set to ‘1’ as RS transmitting MBS data in a dynamic multi-BS MBS mode.
If it has been determined that the RS is a RS transmitting MBS data in the dynamic multi-BS MBS mode at step S230, the BS allocates resource appropriate for the RS transmitting MBS data in the dynamic multi-BS MBS mode at step S240. In more detail, the BS allocates the resource appropriated for the RS transmitting MBS data in the dynamic multi-BS MBS mode such that the resource allocated to the RS can be released when the MS receiving the MBS data from the RS hands over to another cell or stops receiving the MBS data. As described above, when the MBS data transmission is not required, the RS transmitting MBS data in the dynamic multi-BS MBS mode transmits a DSD-REQ message requesting termination of the MBS data transmission to the BS. After allocating the resource to the RS, the BS provides the MBS to the MS via the RS using the resource at step S250.
If it has been determined that the RS is RS transmitting MBS data in a static multi-BS MBS mode at step S230, the BS allocates resource appropriate for the RS transmitting MBS data in the static multi-BS MBS mode such that the RS can relay the MBS data regardless of the communication environment at step S260. After allocating the resource to the RS, the BS provides the MBS to the MS through the resource at step S250.
As described above, the BS checks the capability information of the RSs located within its MBS zone from the SBC-REQ messages transmitted from the RSs, i.e. the necessity of the MBS data transmission and the MBS data transmission modes of the RSs, and allocates resources to the RS depending on variation informed through the DSD-REQ message, whereby the resource are allocated to only the RSs necessary for the MBS data transmission.
The MBS provision method according to this embodiment does not allocate resource to the RSs that are not necessary for the MBS data transmission, thereby preventing waste of resource. Since the resources are not allocated to the RSs unnecessary for the MBS data transmission, there is no need to consider the cumulative delays and waiting times of those RSs, thereby reducing the BS's transmission delay and MS's reception delay, resulting in provision of seamless MBS. A structure and functions of a communication system for providing MBS according to another exemplary embodiment of the present invention is described hereinafter with reference to
Referring to
As aforementioned, the RS 350 transmits an SBC-REQ message including its capability information to the BS1310 through the capability negotiation process in the network entry procedure, and the BS1310 received the SBC-REQ message checks the TLV of the SBC-REQ message (see table 1) to check that the RS 350 is unnecessary for MBS data transmission.
The BS1310 performs resource scheduling and transmits the MBS data based on the checking result. At this time, since the RS 350 does not transmit MBS data in the non-MBS mode, the BS1310 transmits the MBS data through an access link to the MS 340 and transmits a MAP message including MBS-MAP IEs to the MS 340 via relay links provided from the RS 350. Accordingly, the MS 340 receives the MBS data from the BSs 310, 320, and 330 in the multi-BS access scheme and receives the MBS burst information, i.e. the MAP message including the MBS-MAP IEs, via the RS 350.
In this embodiment, since the MBS data is transmitted from multiple BSs 310, 320, and 330 in the multi-BS access scheme, the MS 340 can achieve macro diversity gain. Also, since the MBS data is not transmitted to the RS 350 non-transmitting MBS data in the non-MBS mode, there is no need to allocate resource for transmitting the MBS data but the MAP message including the MBS-MAP IEs, resulting in prevention waste of resource. Since the RS 350 is configured to relay only the MAP message including the MBS-MAP IEs, there is no need to consider the cumulative delay and waiting time of the RS 350 for the MBS data transmission, thereby reducing MBS data transmission delay at the BS1310 and MBS data reception delay at the MS 340, resulting in fast MBS. A structure and functions of a communication system for providing MBS according to another embodiment of the present invention are described hereinafter with reference to
Referring to
As aforementioned, the RS 440 transmits an SBC-REQ message including its capability information to the BS1410 through the capability negotiation process in the network entry procedure, and the BS1410 received the SBC-REQ message checks the TLV of the SBC-REQ message (see table 1) to check that the RS 440 is unnecessary for MBS data transmission.
The BS1410 performs resource scheduling and transmits the MBS data based on the checking result. At this time, since the RS 440 does not transmit MBS data in the non-MBS mode, the BS1410 transmits the MBS data through an access link to the MS 430, whereas the BS1410 transmits a MAP message including the MBS-MAP IEs as well as the MBS data to the RS 440. Accordingly, the MS 430 receives the MBS data from the BSs 410 and 420 in the multi-BS access scheme and receives the MBS burst information, i.e. the MAP message including the MBS-MAP IEs, from the BS1410.
In this embodiment, since the MBS data is transmitted from both the BSs 410 and 420 in the multi-BS access scheme, the MS 430 can achieve macro diversity gain. Also, since the MBS data and the MAP message including the MBS-MAP IEs are not transmitted to the transparent RS 440, there is no need to allocate resource for transmitting the MAP message as well as the MBS data, resulting in prevention waste of resource and protection of unnecessary relay link establishment. Accordingly, there is no need to consider the cumulative delay and waiting time of the RS 440 for the MBS data transmission, thereby reducing MBS data transmission delay at the BS1410 and MBS reception delay at the MS 430. A structure and functions of a communication system for providing MBS according to another embodiment of the present invention are described hereinafter with reference to
Referring to
As aforementioned, each of the RSs 540 and 550 transmits an SBC-REQ message including its capability information to the BS1510 through the capability negotiation process in the network entry procedure, and the BS1510 received the SBC-REQ messages checks the TLVs of the SBC-REQ messages (see table 1) to check the necessities of the MBS data transmission and the MBS data transmission modes of the RSs 540 and 550. From the checking results, the BS1510 finds that the RS1540 transmits MBS data in static or dynamic multi-BS MBS mode and the RS2550 does not transmit MBS data in non-MBS mode based on the TLVs of the SBC-REQ messages.
After checking the necessities of the MBS data transmission and the MBS data transmission modes of the RSs 540 and 550, the BS1510 performs resource scheduling to transmit the MBS data based on the checking results. That is, the BS1510 allocates the resource for MBS data transmission to the RS1540 since it is the non-transparent RS transmitting MBS data in the static or dynamic multi-BS MBS mode, but does not allocate the resource for MBS data transmission to the RS2550 since it is the non-transparent RS does not transmit MBS data in the non-MBS mode. The RS1540 receives and reprocesses the MBS data and burst information, i.e. the MAP message including the MBS-MAP IEs, transmitted from the BS1510 and transmits the reprocessed MBS data and MAP message to the MS 530. In the meantime, the RS2550 receives and reprocesses the MAP message transmitted from the RS1540 depending on the communication environment and then transmits the reprocessed MAP message to the MS 530. In this case, the MS 530 receives the MBS data from the BSs 510 and 520 and RS1540 in the multi-BS access scheme and the MAP message including the MBS-MAP IEs from the RSs 540 and 550.
In this embodiment, since the MBS data is transmitted from the BSs 510 and 520 and the RS1540 in the multi-BS access scheme, the MS 530 can achieve the MBS data with macro diversity gain. Also, the resource for MBS data transmission is allocated to only the non-transparent RS1540 transmitting MBS data in the static or dynamic multi-BS MBS mode but not to the non-transparent RS2550 non-transmitting MBS data in the non-MBS mode, resulting in prevention waste of resource. For this reason, there is no need to consider the cumulative delay and waiting time of the RS2550 for MBS data transmission, thereby reducing MBS data transmission delay at the BS1510 and MBS reception delay at the MS 530, resulting in fast MBS. Furthermore, since the non-transparent RSs 540 and 550 reprocesses the MBS data and/or the MAP message and transmit the reprocessed MBS data and the MAP message to the MS 530, reception rate of signal further increases. A structure and functions of a communication system for providing MBS according to another embodiment of the present invention are described hereinafter with reference to
Referring to
As aforementioned, each of the RSs 640 and 650 transmits an SBC-REQ message including its capability information to the BS1610 through the capability negotiation process in the network entry procedure, and the BS1 received the SBC-REQ messages checks the TLVs of the SBC-REQ messages (see table 1) to check the necessities of the MBS data transmission and the MBS data transmission modes of the RSs 640 and 650. From the TLV checking results, the BS1610 finds that the RS1640 is necessary the MBS data transmission in the static or dynamic multi-BS MBS mode and the RS2 is unnecessary the MBS data transmission in the non-MBS mode.
After checking the necessities of the MBS data transmission and the MBS data transmission modes of the RSs 640 and 650, the BS1610 performs resource scheduling to transmit the MBS data based on the checking results. That is, the RS1610 allocates the resource for MBS data transmission to the RS1640 since it transmits MBS data in the static or dynamic multi-BS MBS mode as the non-transparent RS but does not allocate the resource for MBS data transmission for the RS2 since it does not transmit MBS data in the non-MBS mode regardless of its transparency, i.e. whether it is a transparent RS or a non-transparent RS. The RS1640 receives and reprocesses the MBS data and burst information, i.e. the MAP message including the MBS-MAP IEs, transmitted from the BS1610 depending on the communication environment and transmits MAP message to the MS 630 and transmits the reprocessed MAP message to the RS2650. The RS2650 transmits the MAP message received from the RS1 to the MS 630. In this case, the MS 630 receives the MBS data from the BSs 610 and 620 in the multi-BS access scheme and the RS1640 and the MAP message including the MBS-MAP IEs from the BS1610 and RSs 640 and 650.
In this embodiment, since the MBS data is transmitted from the BSs 610 and 620 and the RS1640 in the multi-BS access scheme, the MS 630 can receive the MBS data with macro diversity gain. Also, the resource for MBS data transmission is allocated to only the non-transparent RS1640 transmitting MBS data in the static or dynamic multi-BS MBS mode but not to the RS2 non-transmitting MBS data in the non-MBS mode, resulting in prevention waste of resource. For this reason, there is no need to consider the cumulative delay and waiting time of the RS2 for MBS data transmission, thereby reducing MBS data transmission delay at the BS1610 and MBS reception delay at the MS 630, resulting in fast MBS. Furthermore, since the non-transparent RSs 640 and 650 reprocess the MBS data and the MAP message and/or the MAP message and transmit the reprocessed MBS data and/or the MAP message to the MS 630, the reception diversity gain further increases.
Although exemplary embodiments of the present invention have been described in detail hereinabove, it should be clearly understood that many variations and/or modifications of the basic inventive concepts herein taught which may appear to those skilled in the present art will still fall within the spirit and scope of the present invention, as defined in the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2007-0108922 | Oct 2007 | KR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/KR08/06382 | 10/29/2008 | WO | 00 | 4/28/2010 |
