1. A method for operating a client station in a wireless local area network (WLAN) communication system comprising an access point, the client station comprising an antenna steering algorithm and a smart antenna responsive to the antenna steering algorithm for selecting one of a plurality of antenna beams, the method comprising:
selecting a preferred antenna beam and at least one alternate antenna beam;
exchanging data with the access point using the preferred antenna beam during a sustained use period during which a re-scan of the other antenna beams is not performed;
at an end of the sustained use period and before a next sustained use period, calculating a quality metric of exchanged data for the preferred antenna beam and for each alternate antenna beam, the calculating comprising
determining at least one link quality metric (LQM) of the exchanged data for the preferred antenna beam,
determining a signal quality metric (SQM) of the exchanged data for the preferred antenna beam, and
combining the at least one LQM and the SQM for calculating the quality metric for the preferred antenna beam, and
repeating the determining and combining for calculating an alternate quality metric for each alternate antenna beam;
comparing the quality metric for the preferred antenna beam to the alternate quality metrics for the alternate antenna beams; and
if the quality metric is less than at least one of the alternate quality metrics, then selecting the alternate antenna beam corresponding to the at least one alternate quality metric having a higher value to continue exchanging data with the access point within the next sustained use period.
2. A method according to claim 1 wherein if there is a plurality of alternate quality metrics greater than the quality metric for the preferred antenna beam, then the selected alternate antenna beam corresponds to the alternate antenna beam having the highest alternate quality metric.
3. A method according to claim 2 further comprising selecting the alternate antenna beam having the next highest alternate quality metric as a new alternate antenna beam.
4. A method according to claim 1 wherein the alternate antenna beam comprises an omni-directional beam.
5. A method according to claim 1 wherein the at least one LQM is based upon at least one estimate of a frame error rate (FER) of the exchanged data.
6. A method according to claim 1 wherein the at least one LQM comprises a downlink LQM and an uplink LQM.
7. A method according to claim 6 wherein a weighting factor is used when combining the downlink LQM and the uplink LQM.
8. A method according to claim 6 wherein the client station comprises a media access control (MAC) layer including a plurality of frame counters for estimating frame error rates of the exchanged data; and wherein a first set of counters is used for determining the downlink LQM and a second set of counters is used for determining the uplink LQM.
9. A method according to claim 1 wherein the at least one LQM is based upon a transfer rate of the exchanged data for the corresponding antenna beam.
10. A method according to claim 1 wherein the at least one LQM is based upon at least one of a throughput and a data rate of the exchanged data for the corresponding antenna beam.
11. A method according to claim 1 wherein the SQM is based upon a received signal strength indicator (RSSI) of the exchanged data.
12. A method according to claim 1 wherein a weighting factor is used when combining the LQM and the SQM.
13. A method according to claim 1 wherein the plurality of antenna beams comprise a plurality of directional beams and an omni-directional beam.
14. A client station for operating in a wireless local area network (WLAN) communication system comprising an access point, the client station comprising:
a switched beam antenna for generating a plurality of antenna beams;
a beam switching unit coupled to said switched beam antenna for selecting a preferred antenna beam and at least one alternate antenna beam;
a transceiver coupled to said beam switching unit for exchanging data with the access point via the preferred antenna beam during a sustained use period during which a re-scan of the other antenna beams is not performed; and
an antenna steering algorithm module for running an antenna steering algorithm, and at an end of the sustained use period and before a next sustained use period, calculating a quality metric of exchanged data for the preferred antenna beam and for each alternate antenna beam, the calculating comprising
determining at least one link quality metric (LQM) of the exchanged data for the preferred antenna beam,
determining a signal quality metric (SQM) of the exchanged data for the preferred antenna beam, and
combining the at least one LQM and the SQM for calculating the quality metric for the preferred antenna beam, and
repeating the determining and combining for calculating an alternate quality metric for each alternate antenna beam;
said antenna steering algorithm module comparing the quality metric for the preferred antenna beam to the alternate quality metrics for the alternate antenna beams, and if the quality metric is less than at least one of the alternate quality metrics, then selecting the alternate antenna beam corresponding to the at least one alternate quality metric having a higher value to continue exchanging data with the access point within the next sustained use period.
15. A client station according to claim 14 wherein if there is a plurality of alternate quality metrics greater than the quality metric for the preferred antenna beam, then the selected alternate antenna beam corresponds to the alternate antenna beam having the highest alternate quality metric.
16. A client station according to claim 15 further comprising selecting the alternate antenna beam having the next highest alternate quality metric as a new alternate antenna beam.
17. A client station according to claim 14 wherein the alternate antenna beam comprises an omni-directional beam.
18. A client station according to claim 14 wherein the at least one LQM is based upon at least one estimate of a frame error rate (FER) of the exchanged data.
19. A client station according to claim 14 wherein the at least one LQM comprises a downlink LQM and an uplink LQM.
20. A client station according to claim 19 wherein a weighting factor is used when combining the downlink LQM and the uplink LQM.
21. A client station according to claim 19 wherein the client station comprises a media access control (MAC) layer including a plurality of frame counters for estimating frame error rates of the exchanged data; and wherein a first set of counters is used for determining the downlink LQM and a second set of counters is used for determining the uplink LQM.
22. A client station according to claim 14 wherein the at least one LQM is based upon a transfer rate of the exchanged data for the corresponding antenna beam.
23. A client station according to claim 14 wherein the at least one LQM is based upon at least one of a throughput and a data rate of the exchanged data for the corresponding antenna beam.
24. A client station according to claim 14 wherein the SQM is based upon a received signal strength indicator (RSSI) of the exchanged data.
25. A client station according to claim 14 wherein a weighting factor is used when combining the LQM and the SQM.
26. A client station according to claim 14 wherein the plurality of antenna beams comprise a plurality of directional beams and an omni-directional beam.
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 for separating solvents and asphaltenes comprising:
combining heavy oil feedstock with a solvent to form a mixture;
performing sonication on the mixture using a sonic reactor to separate deasphalted oil including the a first portion of the solvent from asphaltenes including a second portion of the solvent;
processing the deasphalted oil including the first portion of the solvent to recover the solvent from the deasphalted oil; and
processing the asphaltenes including the second portion of the solvent to recover the solvent from the asphaltenes.
2. The method of claim 1, further comprising:
selecting a solvent from a plurality of alkane including non-polar solvents.
3. The method of claim 2, wherein the solvent is selected based on the amount of asphaltenes in the heavy oil feedstock.
4. The method of claim 1, wherein an amount of solvent mixed with the heavy oil feedstock maintains a predetermined ratio with the heavy oil feedstock based on the level of chemicals contained in the heavy oil feedstock, a designated level of separation of asphaltenes, cost factors associated with the separation process, and market demands.
5. The method of claim 1, wherein the quantity and property of the asphaltenes separated from the mixture depend on the temperature, nature, and quantities of the solvent.
6. The method of claim 1, wherein the sonication is performed for 5 seconds to 2 minutes based on the solvent and the heavy oil feedstock included in the mixture.
7. The method of claim 1, wherein sonication applies a low-frequency, high-amplitude, and high-vibrational energy to the mixture.
8. The method of claim 1, wherein processing the deasphalted oil including the first portion of the solvent to recover the solvent from the deasphalted oil comprises:
distilling the deasphalted oil to recover the solvent.
9. The method of claim 8, wherein the temperature of the distillation depends on the solvent.
10. The method of claim 9, wherein the temperature of the distillation is lower for a lighter solvent than the temperature of the distillation for a heavier solvent.
11. A method for separating solvents and asphaltenes comprising:
combining heavy oil feedstock with a solvent to form a mixture;
performing sonication on the mixture using a sonic reactor to separate deasphalted oil including the a first portion of the solvent from asphaltenes and a second portion of the solvent;
processing the deasphalted oil including the first portion of the solvent to recover the solvent from the deasphalted oil;
processing the asphaltenes and the second portion of the solvent to recover the solvent from the asphaltenes;
collecting the solvent recovered from the deasphalted oil and the asphaltenes;
combining a second batch of heavy oil feedstock with the recovered solvent.
12. The method of claim 11, further comprising:
adding additional solvent to the collected solvent based on a volume ratio with the heavy oil feedstock.
13. The method of claim 11, wherein the sonication is performed for 5 seconds to 2 minutes based on the solvent and the heavy oil feedstock included in the mixture.
14. The method of claim 11, wherein sonication applies a low-frequency, high-amplitude, and high-vibrational energy to the mixture.
15. A solvent and asphaltene separation system comprising:
an in-line mixer configured to receive heavy oil feedstock and solvent and mix the heavy oil feedstock and solvent to form a homogeneous mixture;
a sonicator connected to the in-line mixer and configured to receive the homogeneous mixture from the in-line mixer and apply a low-frequency, high-amplitude, high-vibrational energy to the homogeneous mixture to separate deasphalted oil including a first portion of the solvent from asphaltenes including a second portion of the solvent;
a splitter configured to receive the separated deasphalted oil including the first portion of the solvent from asphaltenes including the second portion of the solvent, direct the deasphalted oil including the first portion of the solvent to a first feedline, and direct the asphaltenes including the second portion of the solvent to a second feedline;
a heat separator vessel connected to the second feedline and configured to receive the asphaltenes including the second portion of the solvent and separate the asphaltenes from the second portion of the solvent by causing the solvent to evaporate; and
a separator connected to the first feedline and configured to receive the deasphalted oil including the first portion of the solvent and separate the deasphalted oil from the solvent.
16. The solvent and asphaltene separation system of claim 15, further comprising:
a first heater that heats the asphaltenes including the second portion of the solvent in the second feedline before the asphaltenes including the second portion of the solvent before the asphaltenes including the second portion of the solvent enter the heat separator vessel.
17. The solvent and asphaltene separation system of claim 16, wherein the heater does not cook the asphaltenes including the second portion of the solvent.
17. The solvent and asphaltene separation system of claim 15, further comprising:
a heat exchanger connected to the heat separator vessel and configured to cool the asphaltenes.
18. The solvent and asphaltene separation system of claim 15, wherein the separator is a two-stage separator comprising:
a flash drum performing the first stage; and
a vacuum or steam distillation performing the second step.
19. The solvent and asphaltene separation system of claim 15, further comprising:
a solvent cleanup vessel connected to the heat separator vessel and the separator and configured to clean the solvent before the solvent is recycled.
20. The solvent and asphaltene separation system of claim 19, further comprising:
a solvent staging area configured to receive recycled solvent from the solvent cleanup vessel, receive additional solvent from a solvent storage tank to maintain a predetermined solvent to heavy oil feedstock ratio, and provide solvent to the in-line mixer.
21. The solvent and asphaltene separation system of claim 15, wherein sonic reactor applies a low-frequency, high-amplitude, high-vibrational energy for 5 seconds to 2 minutes based on the solvent and the heavy oil feedstock included in the homogeneous mixture.