Method and apparatus for medium reservation and medium reservation modification in a communication system with medium reservation modification granted without requiring additional medium arbitration
View Patent ↗Medium reservation modifications can be requested and granted wherein a master device allocates a medium using reservations that are observed by other devices sharing the medium and a slave device complies with reservations by holding data for transmission until its reservation in time arrives by determining a reserved length of an upcoming transmitting opportunity reserved for a slave device, determining, at the slave device, a desired length for transmitting data from the slave device over the medium, comparing the reserved length and the desired length to determine if a medium reservation modification is warranted, if the medium reservation modification is warranted, requesting, using the slave device and the medium, during the reserved time covered by the medium reservation, the medium reservation modification, and determining, at the master device, whether to grant or deny the medium reservation modification and conveying the determination to the slave device.
1. A method for requesting and granting of a medium reservation modification wherein a master device allocates a medium using reservations that are observed by other devices sharing the medium and a slave device complies with reservations by holding data for transmission until its reservation in time arrives, the method comprising:
contending, by the master device, for the medium to obtain a reserved transmitting opportunity, wherein contending is performed between a plurality of devices that each have an ability to take over the medium during a contention period, and wherein the plurality of devices does not include the slave device;
determining, at the slave device, a reserved length of an upcoming transmitting opportunity reserved for that slave device, wherein the upcoming transmitting opportunity is part of the reserved transmitting opportunity reserved by the master device after contending for the medium and making a medium reservation;
determining, at the slave device, a desired length for transmitting data from the slave device over the medium;
comparing the reserved length and the desired length to determine if a medium reservation modification is warranted;
if the medium reservation modification is warranted, requesting the medium reservation modification during the reserved transmitting opportunity, using the slave device and the medium;
determining, at the master device, whether to grant or deny the medium reservation modification and conveying the determination to the slave device before the end of the reserved transmitting opportunity and without requiring a new medium arbitration; and
if the medium reservation modification is granted, transmitting data from the slave device during a modified reservation period that is in compliance with reservation constraints imposed by the master device on the slave device.
2. The method of claim 1 , using an RTS/CTS packet sequence between the slave device and the master device to request and rule on the medium reservation modification.
3. A method for requesting and granting of a medium reservation modification wherein a master device allocates a medium, that is part of a wireless communication system according to an 802.11 specification, wherein allocation is done using reservations that are observed by other devices sharing the medium and a slave device complies with reservations by holding data for transmission until its reservation in time arrives, the method comprising:
contending, by the master device, for the medium to obtain a reserved transmitting opportunity, wherein contending is performed between a plurality of devices that each have an ability to take over the medium during a contention period, and wherein the plurality of devices does not include the slave device;
determining, at the slave device, a reserved length of an upcoming transmitting opportunity reserved for that slave device, wherein the upcoming transmitting opportunity is part of the reserved transmitting opportunity reserved by the master device after contending for the medium and making a medium reservation;
determining, at the slave device, a desired length for transmitting data from the slave device over the medium;
comparing the reserved length and the desired length to determine if a medium reservation modification is warranted;
if the medium reservation modification is warranted, requesting the medium reservation modification during the reserved transmitting opportunity, using the slave device and the medium;
using an RTS/CTS packet sequence between the slave device and the master device to request and rule on the medium reservation modification; and
then, sending a packet from the slave device that complies with the modified medium reservation wherein delays between packets in a sequence are a short interframe spacing (SIFS) or other short delay such that no medium arbitration is required between the packets in the sequence.
4. The method of claim 3 , wherein delays between packets in the sequence are sufficiently short such that no medium arbitration is required between the packets in the sequence.
5. The method of claim 3 , wherein the master device is an 802.11 station comprising hardware compatible with the 802.11 specification.
6. The method of claim 5 , wherein delays between packets in the sequence are short interframe spacing (SIFS) periods.
7. The method of claim 6 , wherein the master device is an 802.11 station comprising hardware compatible with the 802.11 specification.
8. The method of claim 6 , wherein the slave device and master device each uses a different packet sequence to communicate the medium reservation modification requests, wherein packets from the slave device and master device are permitted to contain additional user-level data while a new reservation length is being negotiated, wherein user-level data is data that is conveyed between devices for uses other than to facilitate data transfer between devices.
9. The method of claim 6 , wherein the RTS/CTS packet sequence happens without an arbitration occurring between frame transmissions from the slave device and/or the master device.
10. The method of claim 6 , further comprising one or both of the master device and the slave device generating responses to each other's communications in an interval that is short enough to not require arbitration.
11. The method of claim 10 , wherein the interval is shorter than a time required for a third device, that is neither the slave device nor the master device, to initiate medium arbitration.
12. The method of claim 3 , wherein the RTS/CTS packet sequence happens without an arbitration occurring between frame transmissions from the slave device and/or the master device.
13. The method of claim 3 , further comprising one or both of the master device and the slave device generating responses to each other's communications in an interval that is short enough to not require arbitration.
14. The method of claim 13 , wherein the interval is shorter than a time required for a third device, that is neither the slave device nor the master device, to initiate medium arbitration.
15. A method for requesting and granting of a medium reservation modification wherein a master device allocates a medium, that is part of a wireless communication system according to an 802.11 specification, wherein allocation is done using reservations that are observed by other devices sharing the medium and a slave device complies with reservations by holding data for transmission until its reservation in time arrives, the method comprising:
contending, by the master device, for the medium to obtain a reserved transmitting opportunity, wherein contending is performed between a plurality of devices that each have an ability to take over the medium during a contention period, and wherein the plurality of devices does not include the slave device;
determining, at the slave device, a reserved length of an upcoming transmitting opportunity reserved for that slave device, wherein the upcoming transmitting opportunity is part of the reserved transmitting opportunity reserved by the master device after contending for the medium and making a medium reservation;
determining, at the slave device, a desired length for transmitting data from the slave device over the medium;
comparing the reserved length and the desired length to determine if a medium reservation modification is warranted;
if the medium reservation modification is warranted, requesting the medium reservation modification during the reserved transmitting opportunity, using the slave device and the medium; and
determining, at the master device, whether to grant or deny the medium reservation modification and conveying the determination to the slave device before the end of the reserved transmitting opportunity and without requiring a new medium arbitration; and
wherein the slave device and master device use a packet sequence to communicate the medium reservation modification requests, and wherein the packets from the slave device and master device are permitted to contain additional user-level data while a new reservation length is being negotiated, wherein user-level data is data that is conveyed between devices for uses other than to facilitate data transfer between devices.
16. The method of claim 15 , wherein the packet sequence is an RTS/CTS packet sequence between the slave device and the master device.