IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0631485
(2000-08-03)
|
발명자
/ 주소 |
- Kondylis, George D.
- Krishnamurthy, Srikanth V.
- Dao, Son
|
출원인 / 주소 |
|
대리인 / 주소 |
|
인용정보 |
피인용 횟수 :
59 인용 특허 :
4 |
초록
▼
A real-time multicast scheduler method and apparatus is presented, to facilitate multicasting of real-time variable bit rate data in wireless ad-hoc networks. Variable bit rate traffic cannot tolerate delay jitter. However, a small amount of packet losses may be tolerable. In order to ensure the pro
A real-time multicast scheduler method and apparatus is presented, to facilitate multicasting of real-time variable bit rate data in wireless ad-hoc networks. Variable bit rate traffic cannot tolerate delay jitter. However, a small amount of packet losses may be tolerable. In order to ensure the provisioning of a desired level of quality of service, bandwidth is reserved on the multicast structure. A goal of the real-time multicast scheduler is to avoid packet collisions and to facilitate color re-use, where "color" is defined as a channel selected as a combination of time-division multiple access, frequency-division multiple access, and code-division multiple access schemes. The real-time multicast scheduler provides a self-healing network which corrects for disconnections caused by node movement and nodes moving out of range of each other, while accounting for colors already assigned for data transmission in order to prevent packet collisions.
대표청구항
▼
A real-time multicast scheduler method and apparatus is presented, to facilitate multicasting of real-time variable bit rate data in wireless ad-hoc networks. Variable bit rate traffic cannot tolerate delay jitter. However, a small amount of packet losses may be tolerable. In order to ensure the pro
A real-time multicast scheduler method and apparatus is presented, to facilitate multicasting of real-time variable bit rate data in wireless ad-hoc networks. Variable bit rate traffic cannot tolerate delay jitter. However, a small amount of packet losses may be tolerable. In order to ensure the provisioning of a desired level of quality of service, bandwidth is reserved on the multicast structure. A goal of the real-time multicast scheduler is to avoid packet collisions and to facilitate color re-use, where "color" is defined as a channel selected as a combination of time-division multiple access, frequency-division multiple access, and code-division multiple access schemes. The real-time multicast scheduler provides a self-healing network which corrects for disconnections caused by node movement and nodes moving out of range of each other, while accounting for colors already assigned for data transmission in order to prevent packet collisions. ion including a table of contents for determining in which layer particular user information is stored and the layer control information including a table of contents for determining the address of the particular user information in the layer within which the particular information is stored. 2. The record carrier of claim 1, in which the global control information includes information indicating the number of layers. 3. The record carrier of claim 1, in which the global control information includes information about the contents of the user information in another layer. 4. The record carrier of claim 1 in which the global control information includes information for controlling a lens to remain in focus during scanning of a track of another information layer which is to be read, such control being effected by a servo-system based on the global control information. 5. The record carrier of claim 1 further comprising means for minimizing an access time to read all the first information from the respective layers including: each layer of multiple layers contains one area of control information formatted for containing all the layer control information; the one area of control information formatted for layer control information of each layer co-extends with the area for layer control information contained in all the other layers; the global control information is only contained in the one layer and includes control information for scanning the user information of all the layers; and tracks of information in one of the layers is sequentially ordered in one direction and the tracks of information in a layer adjacent to the one layer is sequentially ordered in the opposite direction. innermost lead-in area of a CD-RW disk, to retrieve a starting time of the innermost lead-in area from ATIP information; accessing a starting point of a PMA area of the disk, on the basis of the starting time of the innermost lead-in area, to retrieve PMA information; on the basis of a time interval between adjoining tracks represented by the PMA information, dividing the tracks into a plurality of sessions and accessing a lead-in area of a last one of the sessions to determine presence/absence and validity of lead-in information in the last session; and only when the lead-in information of the last session is judged to be valid, retrieving the lead-in information of the last session as valid lead-in information. 2. A method as claimed in claim 1 wherein the validity of the lead-in information of the last session is determined on the basis of a combination of one or more of presence/absence of an HF signal, presence/absence of a lead-in area format and presence/absence of a logic erasure format in the lead-in area of the last session and comparison between TOC information included in the lead-in information of the last session and the PMA information. 3. A method as claimed in claim 2 wherein the comparison between the TOC information included in the lead-in information of the last session and the PMA information is made on the basis of one or more of comparisons between track numbers included in the TOC information and PMA information, between track starting times included in the TOC information and PMA information, between an ending time of a track included in the PMA information and a starting time of a next track included in the TOC information and between an ending time of a last track included in the PMA information and a lead-out starting time included in the TOC information. 4. A method of controlling access to individual tracks of an optical disk, after retrieval of disk information from said optical disk, on the basis of PMA information included in the retrieved disk information, said retrieval of disk information from said optical disk being performed by: accessing a given location within an innermost lead-in area of a CD-RW disk, to retrieve a starting time of the innermost lead-in area from ATIP information; accessing a starting point of a PMA area of the disk, on the basis of the starting time of the innermost lead-in area, to retrieve PMA information; on the basis of a time interval between adjoining tracks represented by the PMA information, dividing the tracks into a plurality of sessions and accessing a lead-in area of a last one of the sessions to determine presence/absence and validity of lead-in information in the last session; and only when the lead-in information of the last session is judged to be valid, retrieving the lead-in information of the last session as valid lead-in information. 5. A method of controlling recording on an optical disk after retrieval of disk information from said optical disk, said retrieval of disk information from said optical disk being performed by: accessing a given location within an innermost lead-in area of a CD-RW disk, to retrieve a starting time of the innermost lead-in area from ATIP information; accessing a starting point of a PMA area of the disk, on the basis of the starting time of the innermost lead-in area, to retrieve PMA information; on the basis of a time interval between adjoining tracks represented by the PMA information, dividing the tracks into a plurality of sessions and accessing a lead-in area of a last one of the sessions to determine presence/absence and validity of lead-in information in the last session; and only when the lead-in information of the last session is judged to be valid, retrieving the lead-in information of the last session as valid lead-in information, said method of controlling recording comprising the steps of: when the lead-in information of the last session is judged to be valid, permitting additional writ ing of a next session on condition that a B0 pointer included in Q subcode information of the lead-in information of the last session is other than FF: FF: FF; and when there is no lead-in information in the last session or the lead-in information of the last session is judged to be invalid, permitting additional writing of a track next to the last session or recording, onto the last session, of lead-in and lead-out information to complete the last session. 6. A program code storage medium encoded with instructions which cause an optical disk recording apparatus to access a given location within an innermost lead-in area of a CD-RW disk, to retrieve a starting time of the innermost lead-in area from ATIP information; access a starting point of a PMA area of the disk, based on the starting time of the innermost lead-in area, to retrieve PMA information; based on a time interval between adjoining tracks represented by the PMA information, divide the tracks into a plurality of sessions and to access a lead-in area of a last one of the sessions to determine presence/absence and validity of lead-in information in the last session; and only when the lead-in information of the last session is judged to be valid, retrieve the lead-in information of the last session as valid lead-in information. 7. A program code storage medium as claimed in claim 6, wherein the medium further includes instructions which cause the optical disk recording apparatus to: when the lead-in information of the last session is judged to be valid, permit additional writing of a next session on condition that a B0 pointer included in Q subcode information of the lead-in information of the last session is other than FF: FF: FF; and when there is no lead-in information in the last session or the lead-in information of the last session is judged to be invalid, permit additional writing of a track next to the last session or recording, on to the last session, of lead-in and lead-out information to complete the last session. 8. A method of retrieving disk information from an optical disk comprising the steps of: accessing a given location within an innermost lead-in area of a CD-R disk, to retrieve a starting time of the innermost lead-in area from ATIP information; accessing a starting point of a PMA area of the disk, on the basis of the starting time of the innermost lead-in area, to retrieve PMA information; on the basis of a time interval between adjoining tracks represented by the PMA information, dividing the tracks into a plurality of sessions and accessing a lead-in area of a last one of the sessions to determine presence/absence lead-in information in the last session; when the lead-in information is present in the last session, determining whether a B0 pointer is present in Q subcode information of the lead-in information; when the B0 pointer is present in the Q subcode information of the lead-in information, accessing a lead-in area of a next session on the basis of a starting time of a program area of the next session included in the Q subcode information and determining presence/absence of lead-in information in the next session; and when the lead-in information is present in the next session, retrieving the lead-in information from the next session, whereby readout of the lead-in information across adjoining ones of the sessions is sequentially performed up to a particular one of the sessions where the lead-in information is retrieved any longer or where the B0 pointer is retrieved any longer from the lead-in information. 9. A method of controlling access to individual tracks of an optical disk, after retrieval of disk information from said optical disk, on the basis of PMA information included in the retrieved disk information or, for each session for which no PMA information is included in the disk information, on the basis of lead-in information, said retrieval of disk information from said optical disk being performed by: accessing a given location within an innermost lead-in area of a CD-R disk, to retrieve a starting time of the innermost lead-in area from ATIP information; accessing a starting point of a PMA area of the disk, on the basis of the starting time of the innermost lead-in area, to retrieve PMA information; on the basis of a time interval between adjoining tracks represented by the PMA information, dividing the tracks into a plurality of sessions and accessing a lead-in area of a last one of the sessions to determine presence/absence and validity of lead-in information in the last session; when the lead-in information is present in the last session, determining whether a B0 pointer is present in Q_subcode information of the lead-in information; when the B0 pointer is present in the Q subcode information of the lead-in information, accessing a lead-in area of a next session on the basis of a starting time of a program area of the next session included in the Q subcode information and determining presence/absence of lead-in information in the next session; and when the lead-in information is present in the next session, retrieving the lead-in information from the next session, whereby readout of the lead-in information across adjoining ones of the sessions is sequentially performed up to a particular one of the sessions where the lead-in information is retrieved any longer or where the B0 pointer is retrieved any longer from the lead-in information. 10. A method of controlling recording on an optical disk after retrieval of disk information from said optical disk, said retrieval of disk information from said optical disk being performed by: accessing a given location within an innermost lead-in area of a CD-R disk, to retrieve a starting time of the innermost lead-in area from ATIP information; accessing a starting point of a PMA area of the disk, on the basis of the starting time of the innermost lead-in area, to retrieve PMA information; on the basis of a time interval between adjoining tracks represented by the PMA information, dividing the tracks into a plurality of sessions and accessing a lead-in area of a last one of the sessions to determine presence/absence and validity of lead-in information in the last session; when the lead-in information is present in the last session, determining whether a B0 pointer is present in Q subcode information of the lead-in information; when the B0 pointer is present in the Q subcode information of the lead-in information, accessing a lead-in area of a next session on the basis of a starting time of a program area of the next session included in the Q subcode information and determining presence/absence of lead-in information in the next session; and when the lead-in information is present in the next session, retrieving the lead-in information from the next session, whereby readout of the lead-in information across adjoining ones of the sessions is sequentially performed up to a particular one of the sessions where the lead-in information is retrieved any longer or where the B0 pointer is retrieved any longer from the lead-in information, said method of controlling recording comprising the steps of: when lead-in information is present in an outermost session of said optical disk, permitting additional writing of a next session on condition that a B0 pointer is included in Q subcode information of the lead-in information of the outermost session; and when there is no lead-in information in the outermost session, permitting additional writing of a further session next to the outermost session or recording, onto the outermost session, of lead-in and lead-out information to complete the outermost session. 11. A program code storage medium encoded with instructions which cause an optical disk recording apparatus to access a given location within an innermost lead-in area of a CD-R disk, to retrieve a starting time of the innermost lead-in area from ATIP information; a ccess a starting point of a PMA area of the disk, based on the starting time of the innermost lead-in area, to retrieve PMA information; based on a time interval between adjoining tracks represented by the PMA information, divide the tracks into a plurality of sessions and to access a lead-in area of a last one of the sessions to determine presence/absence of lead-in information in the last session; when the lead-in information is present in the last session, determine whether a B0 pointer is present in Q subcode information of the lead-in information; when the B0 pointer is present in the Q subcode information of the lead-in information, access a lead-in area of a next session based on a starting time of a program area of the next session included in the Q subcode information and to determine presence/absence of lead-in information in the next session; and when the lead-in information is present in the next session, to retrieve the lead-in information from the next session, whereby readout of the lead-in information from the next session across adjoining ones of the sessions is sequentially performed up to a particular one of the sessions where the lead-in information from the next session is not retrieved any longer or where the B0 pointer is not retrieved any longer from the lead-in information from the next session. 12. A program code storage medium as claimed in claim 11, wherein the medium further includes instructions which cause the optical disk recording apparatus to control access to individual tracks of said CD-R disk based on the PMA information included in retrieved disk information or, for each session for which no PMA information is included in the disk information, based on the lead-in information in the last session. 13. A program code storage medium as claimed in claim 12, wherein the medium further includes instructions which cause the optical disk recording apparatus to: when lead-in information is present in an outermost session of said optical disk, permit additional writing of a next session on condition that a B0 pointer is included in Q subcode information of the lead-in information of the outermost session; and when there is no lead-in information in the outermost session, permit additional writing of a further session next to the outermost session or recording, on to the outermost session, of lead-in and lead-out information to complete the outermost session. 14. An optical disk recording method, comprising: identifying whether a type of an optical disk on which recording is to be made is a CD-RW disk or a CD-R disk; if the type of the optical disk is the CD-RW disk, then accessing a given location within an innermost lead-in area of the CD-RW disk, to retrieve a starting time of the innermost lead-in area from ATIP information, accessing a starting point of a PMA area of the CD-RW disk, based on the starting time of the innermost lead-in area, to retrieve PMA information, based on a time interval between adjoining tracks represented by the PMA information, dividing the tracks into a plurality of sessions and accessing a lead-in area of a last one of the sessions to determine presence/absence and validity of lead-in information in the last session, and only when the lead-in information of the last session is judged to be valid, retrieving the lead-in information of the last session as valid lead-in information; and if the type of the optical disk is the CD-R disk, then accessing a given location within an innermost lead-in area of the CD-R disk, to retrieve a starting time of the innermost lead-in area of the CD-R disk from ATIP information of the CD-R disk, accessing a starting point of a PMA area of the CD-R disk, based on the starting time of the innermost lead-in area of the CD-R disk, to retrieve PMA information of the CD-R disk, based on a time interval between adjoining tracks represented by the PMA information of the CD-R disk, dividing the tracks into a plurality o
※ AI-Helper는 부적절한 답변을 할 수 있습니다.