Hybrid contention/polling access method
First Claim
1. A method for controlling transmissions by a plurality of users on a shared medium, the method comprising the steps of:
- maintaining a first list of users that are active;
maintaining a second list of users that are inactive;
maintaining a third list of users that are inactive but have been active within a predetermined interval;
sending a first group-addressed poll message addressed to a first specified group of users in the second list and a second specified group of user in the third list;
authorizing the first and second specified groups of users to transmit on the shared medium; and
when more than one user responds to the first group-addressed poll message, sending an individually-addressed poll message to each user in the second specified group of users, and then subsequently sending a second group-addressed poll message authorizing the users in the first specified group of users transmit on the shared medium.
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Accused Products
Abstract
A system, device, and method for improving access in a hybrid contention/polling protocol maintains a list of active users, a list of recently active users, and a list of inactive users. An active user that becomes inactive is moved into the list of recently active users, and a recently active user that remains inactive is moved into the list of inactive users. A limited contention poll addressed to a number of inactive users and at least one recently active user authorizes any of the addressed users to contend for access to the shared channel. Upon detection of a collision, addressed users that are in the list of recently active users are polled individually, while the inactive users are sent a collision resolution poll which forces the inactive users to contend again for access. Users that become active are moved into the list of active users.
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Citations
16 Claims
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1. A method for controlling transmissions by a plurality of users on a shared medium, the method comprising the steps of:
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maintaining a first list of users that are active; maintaining a second list of users that are inactive; maintaining a third list of users that are inactive but have been active within a predetermined interval; sending a first group-addressed poll message addressed to a first specified group of users in the second list and a second specified group of user in the third list; authorizing the first and second specified groups of users to transmit on the shared medium; and when more than one user responds to the first group-addressed poll message, sending an individually-addressed poll message to each user in the second specified group of users, and then subsequently sending a second group-addressed poll message authorizing the users in the first specified group of users transmit on the shared medium. - View Dependent Claims (2, 3, 4, 5, 10, 11, 12, 13)
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6. A device for controlling transmissions by a plurality of users on a shared medium, the device comprising:
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logic circuitry for maintaining a first list of users that are active; logic circuitry for maintaining a second list of users that are inactive; logic circuitry for maintaining a third list of users that are inactive but have been active within a predetermined interval; logic circuitry for sending a first group-addressed poll message addressed to a a first specified group of users in the second list and a second specified group of users in the third list; logic circuitry for authorizing the first and second specified groups of users to transmit on the shared medium; and logic circuitry for sending an individually-addressed poll message to each user in the second specified group of users when more than one user responds to the first group-addressed poll message, and then subsequently sending a second group-addressed poll message authorizing the first specified group of users to transmit on the shared medium. - View Dependent Claims (7, 14, 15, 16)
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8. A device for supporting a user having data to transmit in an improved hybrid contention/polling protocol over a shared medium, the device comprising:
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logic circuitry for receiving a first group-addressed poll message addressed to a specified group of users authorizing the specified group of users to transmit on the shared medium; logic circuitry for determining whether a user in the specified group of users is in one of an active state and an inactive state; logic circuitry for transmitting a response to the first group-addressed poll message, if the user is in the inactive state and the user is in the specified group of users; logic circuitry for receiving an individually-addressed poll message; logic circuitry for receiving a second group-addressed poll message authorizing only a portion of the specified group of users authorized by the first group-addressed poll message to transmit on the shared medium; and logic circuitry for ignoring the second group-addressed poll message, if the user is in the inactive state and an individually-addressed poll message was received since receiving the first group-addressed poll message.
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9. A system having a single headend unit in communication with at least one Access Interface Unit (AIU) by means of a shared medium, each AIU supporting at least one user, the system utilizing a method for controlling transmissions by the plurality of users on the shared medium comprising the steps of:
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by the headend unit; maintaining a first list of users that are active; maintaining a second list of users that are inactive; maintaining a third list of users that are inactive but have active within a predetermined interval; moving a user in the first list to the third list if the user in the first has no data to transmit; sending a first group-addressed poll message addressed to a first specified group of users in the second list and a second specified group of users in the third list authorizing the first and second specified groups of users to transmit on the shared medium; determining a number of users responding to the first group-addressed poll message; if the number of responding users is exactly one, moving the responding user to the first list; and if the number of responding users is greater than one; sending an individually-addressed poll message to each users in the second specified group of users; and sending a second group-addressed poll message authorizing only the first specified group of users to transmit on the shared medium; and by the AIU; receiving the first group-addressed poll message addressed to the first and second specified groups of users authorizing the the first and second specified groups of users to transmit on the shared medium; determining whether the user is in one of an active state and an inactive state; transmitting a response to the first group-addressed poll message, if the user is in the inactive state and the user is in one of the specified groups; receiving an individually-addressed poll message; receiving a second group-addressed poll message authorizing only the first specified group of users to transmit on the shared medium; and ignoring the second group-addressed poll message, if the user is in the inactive state and an individually-addressed poll message was received since receiving the first group-addressed poll message.
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Specification