1. A method for controlling access of a mobile device to a femtocell base station comprising:
determining whether to allow access of the mobile device to the femtocell base station based on a femtocell-mobile device pathloss for transmissions between the mobile device and the femtocell base station;
applying one or more constraints governing transmission with a mobile device that is not part of a preferred group of mobile devices for the femtocell base station, when access to the femtoceil base station is allowed to the mobile device which is not part of the preferred group of mobile devices,
wherein the one or more constraints comprises a power cap on the power of uplink transmission from the mobile device to the femtocell base station, and
wherein the power cap for the mobile device which is not part of the preferred group is higher than a power cap for other mobile devices that are part of the preferred group.
2. The method as claimed in claim 1 further comprising obtaining measurement data of signal strength of the femtocell base station at the mobile device and assessing the femtocell-mobile device pathloss from the measurement data.
3. The method as claimed in claim 1 wherein determining whether to allow access comprises allowing access only if the femtocell-mobile device pathloss is below a threshold value.
4. The method as claimed in claim 1 further comprising allowing access only if at least one additional condition is satisfied.
5. The method as claimed in claim 4 wherein at least one of the one additional condition specifies that access to the femtocell base station for the mobile device is allowed only if the number of mobile devices which are not part of the preferred group of mobile devices that are accessing the femtocell base station is less than a specified limit.
6. The method as claimed in claim 5 wherein the specified limit varies depending on the number of mobile devices that are part of the preferred group of mobile devices that are accessing the femtocell base station.
7. The method as claimed in claim 4 wherein at least one of the one additional condition specifies that access to the femtocell base station is allowed only if the femtocell base station has the available capacity or resources to support the mobile device.
8. The method as claimed in claim 1 further comprising, when the mobile device is being served by a macrocell base station and access to the femtocell base station is allowed, initiating handover of the mobile device from the macrocell base station to the femtocell base station.
9. The method as claimed in claim 1 wherein, if access to the femtocell base station is allowed to the mobile device, then determining whether to allow access is repeated to determine whether continued access should be allowed to the mobile device.
10. The method as claimed in claim 9 wherein determining whether to allow access is repeated at at least one of: periodic intervals; availability of updated pathloss data; and changes in loading conditions of the femtocell base station.
11. The method as claimed in claim 10 wherein determining whether to allow access is repeated following access to the femtocell of a mobile device which is part of the preferred group of mobile devices for the femtocell base station.
12. The method as claimed in claim 9 wherein, if in the event that access of the mobile device to the femtocell base station is denied, then further comprising initiating handover of the mobile device from the femtocell base cell to a macrocell base station.
13. The method as claimed in claim 1 wherein overall transmission losses between the femtocell and the mobile device are used as an indication of the femtocell-mobile device pathloss.
14. The method as claimed in claim 1 wherein one or more constraint comprises a restriction on the number of frequency resource blocks that can be used in the uplink from the mobile device which is not part of the preferred group to the femtocell base station.
15. The method as claimed in claim 1 where one constraint is a restriction on an amount of power of the femtocell base station transmissions available for downlink transmissions to mobile devices that are not part of the preferred group.
16. The method as claimed in claim 1 where one constraint is a restriction on an amount of resource blocks of the femtocell base station available for downlink transmissions to mobile devices that are not part of the preferred group.
17. The method as claimed in claim 1 wherein whether to allow access is further based on a macrocell-mobile device pathloss for transmissions between the mobile device and a macrocell base station.
18. The method as claimed in claim 17 comprising obtaining measurement data of the signal strength of at least one available macrocell base station at the mobile device and assessing the macrocell-mobile device pathloss from the measurement data.
19. The method as claimed in claim 17 wherein determining whether to allow access comprises allowing access only if the femtocell-mobile device pathloss is lower than the macrocell-mobile device pathloss.
20. The method as claimed in claim 19 wherein determining whether to allow access comprises allowing access only if the femtocell-mobile device pathloss is lower than the macrocell-mobile device pathloss by a threshold amount.
21. A network device for use in a communications network comprising at least one macrocell base station and at least one femtocell base station, the network device comprising memory and a processor, the processor configured to control access of a mobile device to a femtocell base station by allowing access of the mobile device to the femtocell base station based on a femtocell-mobile device pathloss for transmissions between the mobile device and the femtocell base station, wherein, when access to the femtocell base station is allowed to a mobile device that is not part of a preferred group of mobile devices for the femtocell base station, one or more constraints are applied governing transmission with the mobile device that is not part of the preferred group, wherein one constraint comprises a power cap on the power of uplink transmission from the mobile device to the femtocell base station, and the power cap for the mobile device that is not part of the preferred group is higher than a power cap for other mobile devices that are part of the preferred group.
22. The network device as claimed in claim 21 wherein the network device comprises a femotcell base station and the processor is configured control access to the femtocell base station based on a comparison of the femtocell-mobile device pathloss to a threshold value.
23. The network device as claimed in claim 22 wherein the femtocell base station is configured to receive data indicative of femtocell-mobile device pathloss of a mobile device from a macrocell base station which is serving the mobile device.
24. The network device as claimed in claim 22 wherein the femtocell base station is configured to allow a mobile device which is not part of the preferred group of mobile devices to access the femtocell base station as part of controlling access.
25. The network device as claimed in claim 21 wherein the network device comprises at least part of a macrocell base station.
26. The network device as claimed in claim 25 wherein the network device is configured to receive resource information from a femtocell base station.
27. The network device as claimed in claim 21 wherein the network device comprises a gateway device which forms a gateway to the femtocell base station.
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. An image forming apparatus, comprising:
an intermediate transfer medium movable in a sub-scanning direction and on which a toner image is transferred;
a first photosensor including a first light emitting portion for projecting light upon a first side region of the intermediate transfer medium, and a first light receiving portion for receiving light reflected thereby;
a second photosensor including a second light emitting portion for projecting light upon a second side region of the intermediate transfer medium, and a second light receiving portion for receiving light reflected thereby; and
a control unit configured to perform calibration of the first photosensor by (i) using the first light emitting portion of the first photosensor to emit light directly upon an unmarked surface of the intermediate transfer medium, (ii) using the first light receiving portion of the first photosensor to detect an amount of light reflected directly from the unmarked surface of the intermediate transfer medium, and (iii) controlling an amount of light emitted from the first light emitting portion of the first photosensor such that the amount of reflected light detected by the first light receiving portion of the first photosensor is substantially equal to a pre-set reference light amount so as to calibrate the first photosensor,
wherein the control unit is further configured to perform calibration of the second photosensor by (i) using the second light emitting portion of the second photosensor to emit light directly upon an unmarked surface of the intermediate transfer medium, (ii) using the second light receiving portion of the second photosensor to detect an amount of light reflected directly from the unmarked surface of the intermediate transfer medium, and (iii) controlling an amount of light emitted from the second light emitting portion of the second photosensor such that the amount of reflected light detected by the second light receiving portion of the second photosensor is substantially equal to a pre-set reference light amount so as to calibrate the second photosensor,
wherein, after calibration of the first photosensor and the second photosensor, the control unit is configured to control forming toner images representing a first set of image concentration marks comprising a plurality of gray patterns having different concentrations and a second set of image concentration marks comprising a plurality of gray patterns having different concentrations on the image intermediate transfer medium as the intermediate transfer medium is moved in the sub-scanning direction, wherein the first set of image concentration marks and the second set of image concentration marks are separated from each other in a main-scanning direction,
wherein, the control unit is configured to control forming toner images representing a first set of registration marks comprising four different colors and a second set of registration marks comprising four different colors on the intermediate transfer medium as the intermediate transfer medium is moved in the sub-scanning direction, wherein the first set of registration marks and the second set of registration marks are separated from each other in a main-scanning direction,
wherein the first set of registration marks and the first set of image concentration marks are arranged at the first side region of the intermediate transfer medium so as to be detected by the first photosensor, and wherein the second set of registration marks and the second set of image concentration marks are arranged at the second side region of the intermediate transfer medium so as to be detected by the second photosensor, and
wherein a color registration error and an image concentration error are compensated based on information obtained via detection of the toner images representing (i) the first set of registration marks, (ii) the first set of image concentration marks, (iii) the second set of registration marks, and (iv) the second set of image concentration marks formed on the intermediate transfer medium.
2. The image forming apparatus of claim 1, wherein the control unit comprises:
a light amount drift calculator for calculating a first light amount drift of the first photosensor by comparing a light amount that is projected directly upon an unmarked surface of the intermediate transfer medium and reflected directly from the unmarked surface of the intermediate transfer medium and detected by the first light receiving portion with the pre-set reference light amount for calibration of the first photosensor; and
a light emission driver for adjusting an amount of light emitted from the first light emitting portion of the first photosensor, during the calibration thereof, based on the first light amount drift such that, when the adjusted amount of light emitted from the first light emitting portion of the first photosensor is reflected directly from the unmarked surface of the intermediate transfer medium, the reflected light detected by the first light receiving portion, after calibration thereof, is substantially equal to the pre-set reference light amount.
3. The image forming apparatus of claim 2, wherein:
the light amount drift calculator is further configured to calculate a second light amount drift of the second photosensor by comparing a light amount that is projected directly upon an unmarked surface of the intermediate transfer medium and reflected directly from the unmarked surface of the intermediate transfer medium and detected by the second light receiving portion with the pre-set reference light amount for calibration of the second photosensor, and
the light emission driver adjusts an amount of light emitted from the second light emitting portion of the second photosensor, during the calibration thereof, based on the second light amount drift such that, when the adjusted amount of light emitted from the second light emitting portion of the second photosensor is reflected directly from the unmarked surface of the intermediate transfer medium, the reflected light detected by the second light receiving portion, after calibration thereof, is substantially equal to the pre-set reference light amount.
4. The image forming apparatus of claim 3, wherein the light emission driver is configured to control the amount of light emitted from the second emitting portion of the second photosensor by increasing or decreasing a current value supplied to the second light emitting portion.
5. The image forming apparatus of claim 2, wherein the light emission driver is configured to control the amount of light emitted from the first emitting portion of the first photosensor by increasing or decreasing a current value supplied to the first light emitting portion.
6. The image forming apparatus of claim 1, wherein the first set of image concentration marks and the second set of image concentration marks are formed on opposite sides of the intermediate transfer medium separated in the main scanning direction.
7. The image forming apparatus of claim 6, wherein the plurality of gray patterns having different concentrations are arranged in the sub-scanning direction.
8. The image forming apparatus of claim 7, wherein each of the first and second sets of image concentration marks comprises image concentration marks for four different colors.
9. A method for use in an image forming apparatus, the method comprising:
calibrating a first photosensor by (i) using a first light emitting portion of the first photosensor to emit light directly upon an unmarked surface of an intermediate transfer medium, (ii) using a first light receiving portion of the first photosensor to detect an amount of light reflected directly from the unmarked surface of the intermediate transfer medium, and (iii) controlling an amount of light emitted from the first light emitting portion of the first photosensor such that the amount of reflected light detected by the first light receiving portion of the first photosensor is substantially equal to a pre-set reference light amount so as to calibrate the first photosensor; and
calibrating a second photosensor by (i) using a second light emitting portion of the second photosensor to emit light directly upon an unmarked surface of the intermediate transfer medium, (ii) using a second light receiving portion of the second photosensor to detect an amount of light reflected directly from the unmarked surface of the intermediate transfer medium, and (iii) controlling an amount of light emitted from the second light emitting portion of the second photosensor such that the amount of reflected light detected by the second light receiving portion of the second photosensor is substantially equal to a pre-set reference light amount so as to calibrate the second photosensor,
wherein, after calibration of the first photosensor and the second photosensor, the method further comprises:
forming toner images representing a first set of image concentration marks comprising a plurality of gray patterns having different concentrations and a second set of image concentration marks comprising a plurality of gray patterns having different concentrations on the image intermediate transfer medium as the intermediate transfer medium is moved in the sub-scanning direction, wherein the first set of image concentration marks and the second set of image concentration marks are separated from each other in a main-scanning direction;
forming toner images representing a first set of registration marks comprising four different colors and a second set of registration marks comprising four different colors on the intermediate transfer medium as the intermediate transfer medium is moved in the sub-scanning direction, wherein the first set of registration marks and the second set of registration marks are separated from each other in a main-scanning direction,
wherein the first set of registration marks and the first set of image concentration marks are arranged at the first side region of the intermediate transfer medium so as to be detected by the first photosensor, and wherein the second set of registration marks and the second set of image concentration marks are arranged at the second side region of the intermediate transfer medium so as to be detected by the second photosensor; and
compensating a color registration error and an image concentration error based on information obtained via detection of the toner images representing (i) the first set of registration marks, (ii) the first set of image concentration marks, (iii) the second set of registration marks, and (iv) the second set of image concentration marks formed on the intermediate transfer medium.
10. The method of claim 9, further comprising:
calculating a first light amount drift of the first photosensor by comparing a light amount that is projected directly upon an unmarked surface of the intermediate transfer medium and reflected directly from the unmarked surface of the intermediate transfer medium and detected by the first light receiving portion with the pre-set reference light amount for calibration of the first photosensor; and
adjusting an amount of light emitted from the first light emitting portion of the first photosensor, during the calibration thereof, based on the first light amount drift such that, when the adjusted amount of light emitted from the first light emitting portion of the first photosensor is reflected directly from the unmarked surface of the intermediate transfer medium, the reflected light detected by the first light receiving portion, after calibration thereof, is substantially equal to the pre-set reference light amount.
11. The method of claim 10, wherein the adjusting an amount of light emitted from the first light emitting portion of the first photosensor comprises controlling the amount of light emitted from the first emitting portion of the first photosensor by increasing or decreasing a current value supplied to the first light emitting portion.
12. The method of claim 9, further comprising:
calculating a second light amount drift of the second photosensor by comparing a light amount that is projected directly upon an unmarked surface of the intermediate transfer medium and reflected directly from the unmarked surface of the intermediate transfer medium and detected by the second light receiving portion with the pre-set reference light amount for calibration of the second photosensor; and
adjusting an amount of light emitted from the second light emitting portion of the second photosensor, during the calibration thereof, based on the second light amount drift such that, when the adjusted amount of light emitted from the second light emitting portion of the second photosensor is reflected directly from the unmarked surface of the intermediate transfer medium, the reflected light detected by the second light receiving portion, after calibration thereof, is substantially equal to the pre-set reference light amount.
13. The method of claim 12, wherein the adjusting an amount of light emitted from the second light emitting portion of the second photosensor comprises controlling the amount of light emitted from the second emitting portion of the second photosensor by increasing or decreasing a current value supplied to the second light emitting portion.
14. The method of claim 9, wherein the first set of image concentration marks and the second set of image concentration marks are formed on opposite sides of the intermediate transfer medium separated in the main scanning direction.
15. The method of claim 14, wherein the plurality of gray patterns having different concentrations are arranged in the sub-scanning direction.
16. The method of claim 15, wherein each of the first and second sets of image concentration marks comprises image concentration marks for four different colors.