1. A reamer shoe for mounting on a tubing string, the reamer shoe having a reaming area supporting a plurality of discrete reaming members, wherein the plurality of reaming members have complete circumferential coverage of the shoe body but the individual reaming members are non-continuous and do not fully extend either longitudinally along or circumferentially around the reaming area on the shoe body.
2. A reamer shoe as claimed in claim 1 wherein the reaming members are diamond shaped.
3. A reamer shoe as claimed in claim 1 wherein the reaming members are formed as discrete simple geometrical shapes.
4. A reamer shoe as claimed in any one of the preceding claims wherein the reaming members are separated by void areas which permit by pass of fluid over the reaming area, between the reaming members.
5. A reamer shoe as claimed in any one of the preceding claims having a plurality of flow by areas or flow ports to allow lubrication of the shoe.
6. A reamer shoe as claimed in any one of the preceding claims wherein the reaming members are made of a hard wearing and resistant material, such as tungsten carbide or polycrystalline diamond.
7. A reamer shoe as claimed in any one of the preceding claims wherein the reaming members are securely attached to the shoe body by a welding process.
8. A reamer shoe as claimed in any one of the preceding claims 1 to 6 wherein the reaming members are securely attached to the shoe body by a mechanical locking technique.
9. A reamer shoe as claimed in any one of the preceding claims having connection means for mounting the reamer shoe on a tubing string.
10. A reamer shoe as claimed in any one of the preceding claims having an internal diameter which is at least equal to, or greater than the internal diameter of the casing.
11. A reamer shoe as claimed in any one of the preceding claims further comprising a stabiliser or centraliser.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method comprising:
a transmitting station monitoring a shared-communications medium for an opportunity to transmit a first signal and a second signal via the shared-communications medium;
the transmitting station transmitting the second signal using a second modulation format on the shared communications medium, the second signal conveying a particular frame that includes a destination address of the transmitting station and indicates a duration for which the shared-communications medium is reserved, and
the transmitting station transmitting the first signal in accordance with a first modulation format on the shared-communications medium after the second signal without waiting for a responsive transmission to the second signal, wherein the first signal conveys at least one data frame within the duration indicated in the particular frame.
2. The method of claim 1, wherein the second modulation format is different than the first modulation format.
3. The method of claim 1, wherein the first modulation format comprises orthogonal frequency division multiplexing (OFDM) and the second modulation format comprises complementary code keying (CCK).
4. The method of claim 1, further comprising the transmitting station
transmitting a third signal on the shared-communications medium within the duration indicated in the particular frame, wherein the third signal conveys a data frame in accordance with the second modulation format that reinforces the duration indicated in the particular frame.
5. The method of claim 1, wherein the particular frame and the at least one data frame are each addressed to different destination addresses.
6. The method of claim 1, wherein the duration indicates an expected transmission time of the at least one data frame.
7. The method of claim 1, wherein the duration indicates, to a receiving station, to refrain from transmitting for the duration.
8. A station comprising:
a transmitter for transmitting a first signal and a second signal on a shared communications medium, the transmitter configured to:
transmit the second signal using a second modulation format on the shared-communications medium, the second signal conveying a particular frame that includes a destination address of the transmitting station, the second signal further indicating a duration; and
transmit the first signal in accordance with a first modulation format on the shared-communications medium after the second signal without waiting for a responsive transmission to the second signal, wherein the first signal conveys at least one data frame within the duration.
9. The station of claim 8, wherein the second modulation format is different than the first modulation format.
10. The station of claim 8, wherein the first modulation format comprises orthogonal frequency division multiplexing (OFDM) and the second modulation format comprises complementary code keying (CCK).
11. The station of claim 8, wherein the transmitter also transmits a third signal on the shared-communications medium, conveying a data frame in accordance with the second modulation format that reinforces the duration indicated in the particular frame.
12. The station of claim 8, wherein the particular frame and the at least one data frame are each addressed to different destination addresses.
13. The station of claim 8, wherein the duration indicates an expected transmission time of the at least one data frame.
14. The station of claim 8, wherein the duration indicates, to a receiving station, to refrain from transmitting for the duration.
15. A method comprising:
monitoring a shared-communications medium at a transmitting station for an opportunity to transmit a first signal, a second signal, and a third signal via the shared-communications medium;
transmitting the second signal from the transmitting station in accordance with a second modulation format on the shared-communications medium, the second signal conveying a particular frame that includes a destination address of the transmitting station and indicates a duration for which the shared-communications medium is reserved;
transmitting the first signal from the transmitting station in accordance with a first modulation format on the shared-communications medium after the second signal without waiting for a responsive transmission to the second signal, wherein the first signal conveys at least one data frame within the duration indicated in the particular frame; and
transmitting the third signal from the transmitting station in accordance with the second modulation format on the shared communications medium after the first signal, wherein the third signal conveys a data frame.
16. The method of claim 15, wherein the second modulation format is different than the first modulation format.
17. The method of claim 15, wherein the first modulation format comprises orthogonal frequency division multiplexing (OFDM) and the second modulation format comprises complementary code keying (CCK).
18. The method of claim 15, wherein the particular frame and the at least one data frame are each addressed to different destination addresses.
19. The method of claim 15, wherein the shared-communications medium is operative in the 2.4 GHz Industrial, Scientific, Medical band of the radio frequency spectrum.
20. The method of claim 15, wherein the duration indicates an expected transmission time of the at least one data frame.
21. The method of claim 15, wherein the duration indicates, to a receiving station, to refrain from transmitting for the duration.
22. A station comprising:
a transmitter for transmitting a first signal, a second signal, and a third signal on a shared communications medium, the transmitter configured to:
transmit the second signal in accordance with a second modulation format on the shared-communications medium, the second signal conveying a particular frame that includes a destination address of the station and indicates a duration for which the shared communications medium is reserved;
transmit the first signal in accordance with a first modulation format on the shared-communications medium after the second signal without waiting for a responsive transmission to the second signal, wherein the first signal conveys at least one data frame within the duration; and
transmit the third signal in accordance with the second modulation format on the shared communications medium after the first signal, wherein the third signal conveys another data frame within the duration indicated in the particular frame.
23. The station of claim 22, wherein the second modulation format is different than the first modulation format.
24. The station of claim 22, wherein the first modulation format comprises orthogonal frequency division multiplexing (OFDM) and the second modulation format comprises complementary code keying (CCK).
25. The station of claim 22, wherein the transmitter also transmits the third signal on the shared-communications medium, conveying a data frame in accordance with the second modulation format that reinforces the duration indicated in the particular frame.
26. The station of claim 22, wherein the particular frame and the at least one data frame are each addressed to different destination addresses.
27. The station of claim 22, wherein the duration indicates, to a receiving station, to refrain from transmitting for the duration.
28. A station comprising: means for transmitting a second signal using a second modulation format on a shared-communications medium, the second signal conveying a particular frame that includes a destination address of the transmitting station and indicates a duration for which the shared-communications medium is reserved; and
means for transmitting a first signal in accordance with a first modulation format on the shared-communications medium after the second signal without waiting for a responsive transmission to the second signal, wherein the first signal conveys at least one data frame within the duration indicated in the particular frame.
29. A station comprising:
a processor;
a transmitter capable of transmitting on a shared-communications medium; and a memory storing processor-executable instructions that, when executed by the processor, cause the processor to perform operations comprising:
monitoring the shared-communications medium for an opportunity to transmit a first signal and a second signal via the shared-communications medium;
transmitting the first signal from the transmitting station in accordance with a first modulation format on the shared-communications medium after the second signal without waiting for a responsive transmission to the second signal,
transmitting the first signal from the transmitting station in accordance with a first modulation format on the shared-communications medium after the second signal, wherein the first signal conveys at least one data frame within the duration indicated in the particular frame.
30. The method of claim 1, further comprising transmitting the first signal immediately after transmitting the second signal.
31. The method of claim 30, wherein the particular frame is one of a clear-to-send (CTS) frame and a null data frame.
32. The station of claim 8, further comprising transmitting the first signal immediately after transmitting the second signal.
33. The station of claim 32, wherein the particular frame is one of a clear-to-send (CTS) frame and a null data frame.
34. The station of claim 28, wherein the means for transmitting the first signal transmits the first signal immediately after the means for transmitting the second signal transmits the second signal.
35. The station of claim 34, wherein the particular frame is one of a clear-to-send (CTS) frame and a null data frame.
36. The station of claim 29, wherein transmitting the first signal further comprises transmitting the first signal immediately after transmitting the second signal.
37. The station of claim 36, wherein the particular frame is one of a clear-to-send (CTS) frame and a null data frame.