1. A method, comprising:
coordinating with a neighboring base station to assign uplink resources for an uplink signal from a mobile device in an uplink coordinated multi-point environment;
signaling information that identifies the uplink resources to the mobile device; and
receiving the uplink signal from the mobile device upon the uplink resources.
2. The method of claim 1, further comprising coordinating with the neighboring base station to schedule the uplink signal from the mobile device and a disparate uplink signal from an interfering mobile device on at least one of different subframes or different subbands.
3. The method of claim 1, wherein the uplink signal is a sounding reference signal (SRS).
4. The method of claim 3, wherein the SRS is an uplink pilot evaluated for channel estimation.
5. The method of claim 1, further comprising transmitting an acknowledgment to the mobile device via downlink resources identified as a function of the uplink resources, the downlink resources being distinct from disparate downlink resources utilized for transmitting an acknowledgment to a disparate mobile device from the neighboring base station.
6. The method of claim 5, wherein the downlink resources used for the acknowledgment for the mobile device differ from the disparate downlink resources used for the acknowledgment for the disparate mobile device when the uplink resources employed by the mobile device are substantially similar to uplink resources assigned to the disparate mobile device for a disparate uplink signal.
7. The method of claim 1, wherein a hopping tree is defined across base stations in the uplink coordinated multi-point environment.
8. The method of claim 7, further comprising:
identifying the mobile device and a disparate mobile device as interfering with each other; and
coordinating with the neighboring base station to assign the mobile device to a first node of the hopping tree and the disparate mobile device to a second node of the hopping tree, wherein the first node maps to the uplink resources and the second node maps to disparate, non-overlapping uplink resources.
9. The method of claim 1, wherein the uplink signal is a pilot.
10. The method of claim 9, further comprising assigning a Zadoff-Chu sequence corresponding to a non-serving base station to the mobile device to orthogonalize the pilot.
11. The method of claim 1, further comprising:
assigning the uplink resources corresponding to a node from a hopping tree to the mobile device for sending the uplink signal; and
transmitting an acknowledgment to the mobile device via downlink resources recognized as a function of an identity of the hopping tree and the uplink resources corresponding to the node from the hopping tree.
12. The method of claim 11, wherein a plurality of hopping trees is employed across base stations in the uplink coordinated multi-point environment.
13. The method of claim 11, wherein uplink resources corresponding to a node from a disparate hopping tree are assigned to a disparate mobile device for sending a disparate uplink signal.
14. The method of claim 13, wherein the node from the hopping tree and the node from the disparate hopping tree map to substantially similar uplink resources over time.
15. The method of claim 13, wherein the node from the hopping tree and the node from the disparate hopping tree map to different uplink resources over time.
16. The method of claim 15, wherein the hopping tree and the disparate hopping tree utilize different hopping sequences.
17. The method of claim 16, wherein the different hopping sequences are at least one of cell-specific hopping sequences or cluster-based hopping sequences.
18. The method of claim 16, wherein the different hopping sequences are each defined as a series of a cell-specific permutation and a cluster-specific permutation.
19. A wireless communications apparatus, comprising:
at least one processor configured to:
assign uplink resources for an uplink signal from a mobile device by coordinating with a neighboring base station over a backhaul in an uplink coordinated multi-point environment;
transmit information that indicates the uplink resources as assigned to the mobile device; and
obtain the uplink signal from the mobile device upon the uplink resources.
20. The wireless communications apparatus of claim 19, wherein the uplink signal is a sounding reference signal.
21. The wireless communications apparatus of claim 19, further comprising:
at least one processor configured to:
coordinate with the neighboring base station over the backhaul to schedule the uplink signal from the mobile device and a disparate uplink signal from an interfering mobile device on at least one of different subframes or different subbands.
22. The wireless communications apparatus of claim 19, further comprising:
at least one processor configured to:
send an acknowledgment to the mobile device via downlink resources identified as a function of the uplink resources, the downlink resources being distinct from disparate downlink resources utilized for transmitting an acknowledgment to a disparate mobile device from the neighboring base station.
23. The wireless communications apparatus of claim 19, wherein a hopping tree is defined across base stations in the uplink coordinated multi-point environment.
24. The wireless communications apparatus of claim 23, further comprising:
at least one processor configured to:
coordinate with the neighboring base station over the backhaul to assign the mobile device to a first node of the hopping tree and a disparate mobile device to a second node of the hopping tree, wherein the first node maps to the uplink resources and the second node maps to disparate, non-overlapping uplink resources.
25. The wireless communications apparatus of claim 19, further comprising:
at least one processor configured to:
assign the uplink resources corresponding to a node from a hopping tree to the mobile device for sending the uplink signal; and
transmit an acknowledgment to the mobile device via downlink resources recognized as a function of an identity of the hopping tree and the uplink resources corresponding to the node from the hopping tree.
26. The wireless communications apparatus of claim 25, wherein a plurality of hopping trees is employed across base stations in the uplink coordinated multi-point environment.
27. The wireless communications apparatus of claim 25, wherein uplink resources corresponding to a node from a disparate hopping tree are assigned to a disparate mobile device for sending a disparate uplink signal.
28. The wireless communications apparatus of claim 27, wherein the node from the hopping tree and the node from the disparate hopping tree map to substantially similar uplink resources over time.
29. The wireless communications apparatus of claim 27, wherein the node from the hopping tree and the node from the disparate hopping tree map to different uplink resources over time.
30. An apparatus, comprising:
means for cooperating with a neighboring base station to assign uplink resources corresponding to a node from a hopping tree to a mobile device for sending an uplink signal in a coordinated multi-point environment;
means for signaling information that indicates the uplink resources to the mobile device; and
means for receiving the uplink signal from the mobile device upon the uplink resources.
31. The apparatus of claim 30, further comprising means for transmitting an acknowledgment to the mobile device via downlink resources recognized as a function of an identity of the hopping tree and the uplink resources corresponding to the node from the hopping tree.
32. The apparatus of claim 30, wherein a plurality of hopping trees is employed across base stations in the coordinated multi-point environment.
33. The apparatus of claim 30, wherein uplink resources corresponding to a node from a disparate hopping tree are assigned to a disparate mobile device for sending a disparate uplink signal.
34. The apparatus of claim 33, wherein the node from the hopping tree and the node from the disparate hopping tree map to substantially similar uplink resources over time.
35. The apparatus of claim 33, wherein the node from the hopping tree and the node from the disparate hopping tree map to different uplink resources over time.
36. The apparatus of claim 30, wherein the uplink signal is a sounding reference signal.
37. A computer program product, comprising:
a computer-readable medium comprising:
code for causing at least one computer to cooperate with a neighboring base station to assign uplink resources corresponding to a node from a hopping tree to a mobile device for sending an uplink signal in a coordinated multi-point environment;
code for causing at least one computer to signal information that identifies the uplink resources to the mobile device; and
code for causing at least one computer to receive the uplink signal from the mobile device upon the uplink resources.
38. The computer program product of claim 37, wherein the computer-readable medium further comprises code for causing at least one computer to transmit an acknowledgment to the mobile device via downlink resources recognized as a function of an identity of the hopping tree and the uplink resources corresponding to the node from the hopping tree.
39. The computer program product of claim 37, wherein a plurality of hopping trees is employed across base stations in the coordinated multi-point environment.
40. The computer program product of claim 37, wherein uplink resources corresponding to a node from a disparate hopping tree are assigned to a disparate mobile device for sending a disparate uplink signal.
41. The computer program product of claim 40, wherein the node from the hopping tree and the node from the disparate hopping tree map to substantially similar uplink resources over time.
42. The computer program product of claim 40, wherein the node from the hopping tree and the node from the disparate hopping tree map to different uplink resources over time.
43. The computer program product of claim 37, wherein the uplink signal is a sounding reference signal.
44. An apparatus, comprising:
a coordinated scheduling component that cooperates with a disparate base station to assign uplink resources to a mobile device for sending an uplink signal in an uplink coordinated multi-point environment;
a reception component that receives the uplink signal sent by the mobile device; and
a channel estimation component that performs channel estimation based upon the uplink signal.
45. The apparatus of claim 44, further comprising an acknowledgment (ACK) transmission component that transmits an acknowledgment to the mobile device via downlink resources recognized as a function of the uplink resources, the downlink resources being distinct from disparate downlink resources utilized for transmitting an acknowledgment to a disparate mobile device from the disparate 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. A fixing device to fix an unfixed image on a recording material in a fixing nip, the fixing device comprising:
a rotatable fixing member to contact the unfixed image;
a pressing member to contact the fixing member and form the fixing nip between the pressing member and the fixing member;
a heater to heat the fixing member with electric power from a power source;
multiple sub-heaters disposed in the heater to heat respective heating areas, arrayed in a direction perpendicular to a direction in which a recording material is conveyed;
a temperature sensor to detect a temperature of the heater; and
a heating controller to control the heater by controlling the multiple sub-heaters individually to heat the respective heating areas, such that a temperature at a portion of the fixing member corresponding to a blank area of the recording medium is lower than a temperature of a portion of the fixing member corresponding to an imaged area of the recording medium,
the heating controller further changing a size of a preliminary heating area by changing a duration of a preliminary heating to preliminarily heat the respective heating areas before the imaged area enters the fixing nip according to the temperature detected by the temperature sensor.
2. The fixing device according to claim 1, wherein the heater is a heating element configured to contact the fixing member to increase a temperature of the fixing member, and
the heating controller sets the preliminary heating area to be smaller than a reference preliminary heating area when the temperature sensor detects a temperature of the heater higher than a predetermined temperature.
3. The fixing device according to claim 2, wherein the heating controller sets the preliminary heating area to be equal to or larger than a reference preliminary heating area when the temperature sensor detects a temperature of the heater not higher than the predetermined temperature.
4. The fixing device according to claim 1, wherein the heating controller sets the preliminary heating area to be smaller than a reference preliminary heating area when a voltage of the power source exceeds a predetermined voltage.
5. The fixing device according to claim 1, wherein the heating controller has multiple threshold temperatures for changing the size of the preliminary heating area according to the temperature detected by the temperature sensor.
6. An image forming apparatus comprising the fixing device according to claim 1.
7. A fixing device to fix an unfixed image on a recording material in a fixing nip, the fixing device comprising:
a rotatable fixing member to contact the unfixed image;
a pressing member to contact the fixing member and form the fixing nip between the pressing member and the fixing member;
a heater to heat the fixing member with electric power from a power source;
multiple sub-heaters disposed in the heater to heat respective heating areas, arrayed in a direction perpendicular to a direction in which a recording material is conveyed;
a temperature sensor to detect a temperature of the heater; and
a heating controller to control the heater by controlling the multiple sub-heaters individually to heat the respective heating areas, such that a temperature at a portion of the fixing member corresponding to a blank area of the recording medium is lower than a temperature of a portion of the fixing member corresponding to an imaged area of the recording medium,
the heating controller further changing a size of a preliminary heating area to preliminarily heat the respective heating areas before the imaged area enters the fixing nip according to the temperature detected by the temperature sensor,
wherein the heating controller sets the preliminary heating area to be smaller than a reference preliminary heating area when a voltage of the power source exceeds a predetermined voltage.
8. A fixing device to fix an unfixed image on a recording material in a fixing nip, the fixing device comprising:
a rotatable fixing member to contact the unfixed image;
a pressing member to contact the fixing member and form the fixing nip between the pressing member and the fixing member;
a heater to heat the fixing member with electric power from a power source;
multiple sub-heaters disposed in the heater to heat respective heating areas, arrayed in a direction perpendicular to a direction in which a recording material is conveyed;
a temperature sensor to detect a temperature of the heater; and
a heating controller to control the heater by controlling the multiple sub-heaters individually to heat the respective heating areas, such that a temperature at a portion of the fixing member corresponding to a blank area of the recording medium is lower than a temperature of a portion of the fixing member corresponding to an imaged area of the recording medium,
the heating controller further changing a size of a preliminary heating area to preliminarily heat the respective heating areas before the imaged area enters the fixing nip according to the temperature detected by the temperature sensor,
wherein the heating controller has multiple threshold temperatures for changing the size of the preliminary heating area according to the temperature detected by the temperature sensor.