Handover processing in multiple access point deployment system

• US 8,036,178 B2
• Filed: 02/15/2011
• Issued: 10/11/2011
• Est. Priority Date: 03/18/2008
• Status: Expired due to Fees

• Current Assignee: Ingenu Inc.
• Original Assignee: Matthew Hughes, Robert W. Boesel, Theodore J. Myers
• Inventors: Hughes, Matthew, Myers, Theodore J., Boesel, Robert W.
• Primary Examiner(s): Pezzlo; John
• Application Number:
  US13/027,654
• Publication Number:
  US 20110128938A1
• Time in Patent Office: 238 Days
• Field of Search: 370/331, 370/442, 370/419
• US Class Current: 370/331
• CPC Class Codes: H03J 7/02 Automatic frequency control H03J7/18 takes precedence
• CPC Class Codes: H04B 1/7103 the interference being multiple access interference
• CPC Class Codes: H04J 13/00 Code division multiplex systems for frequency hopping H04B1/713
• CPC Class Codes: H04J 13/0029 Gold
• CPC Class Codes: H04J 3/0685 Clock or time synchronisation in a node; Intranode synchronisation
• CPC Class Codes: H04L 1/0038 Blind format detection for detection of modulation format H04L27/0012
• CPC Class Codes: H04L 1/0046 Code rate detection or code type detection H04L1/0038 takes precedence; detection of the data rate H04L25/0262; for packet format H04L1/0091
• CPC Class Codes: H04L 1/0057 Block codes H04L1/0061, H04L1/0064 take precedence
• CPC Class Codes: H04L 1/0061 Error detection codes
• CPC Class Codes: H04L 1/1819 with retransmission of additional or different redundancy
• CPC Class Codes: H04L 1/1867 Arrangements specially adapted for the transmitter end
• CPC Class Codes: H04L 2027/0065 Frequency error detectors H04L2027/0067 takes precedence
• CPC Class Codes: H04L 27/233 using non-coherent demodulation
• CPC Class Codes: H04L 7/0004 Initialisation of the receiver H04L7/0075 and H04L7/10 take precedence

Abstract

This disclosure relates to method, device and system for performing handover processing. A roaming list is configured at a receiver which includes multiple entries. Each entry of the roaming list includes receive parameters. A measurement operation is performed on an entry of the roaming list. A transmitter is set based on the measurement operation. Finally, an uplink signal is transmitted to an access point at a time based on a slot start time and a random timing offset. The uplink signal is transmitted while a second signal is transmitted from another node.

Claims

1. A method of handover processing comprising:

configuring at a receiver a roaming list comprising a plurality of entries, wherein each entry comprises one or more receive parameters of the receiver;

performing a measurement operation at the receiver on a current entry of the roaming list;

selecting an entry of the roaming list based on the measurement operation;

setting a transmitter based on the selected entry of the roaming list; and

transmitting an uplink signal to an access point at a time based on a slot start time and a random timing offset, and wherein the uplink signal is transmitted while at least a portion of a second signal is transmitted from a second node such that both the uplink signal and the second signal are received.

2. The method of claim 1, wherein an entry of the roaming list comprises a center frequency and a gold code.

3. The method of claim 1, wherein the roaming list is received by the receiver during a prior transmission.

4. The method of claim 3, wherein the roaming list is received by the receiver at a particular prearranged time.

5. The method of claim 3, wherein the roaming list is received by the receiver at a particular prearranged frequency and at a particular prearranged gold code.

6. The method of claim 1, wherein the measurement operation comprises setting the receiver based on the current entry, measuring an RSSI metric at the receiver, and recording the RSSI metric;

and wherein the entry of the roaming list is selected based on a greatest RSSI metric.

7. The method of claim 6, wherein the RSSI metric is based in part on a downlink RSSI measurement minus an access point interference signal.

8. The method of claim 1, wherein the measurement operation comprises recording a frequency estimate and a timing estimate into the roaming list based on a successful demodulation of a broadcast channel and wherein the receiver is set based on a recorded frequency estimate and a recorded timing estimate.

9. The method of claim 1, wherein the roaming list is ordered into a priority list based on previous iterations of the measurement operation.

10. The method of claim 9, further comprising:

moving the selected entry to a last entry of the priority list;

repeating the measurement operation for each entry in the priority list;

selecting a second entry of the priority list based in part on a second measurement operation; and

setting the transmitter based on the selected second entry of the roaming list.

11. The method of claim 1, wherein repeating the measurement operation for each entry of the roaming list is interrupted when the measurement operation produces a result greater than a threshold value.

12. A node comprising:

a processor;

a receiver operatively coupled to the processor and configured to configure a roaming list comprising a plurality of entries, wherein each entry comprises one or more receive parameters of the receiver;

perform a measurement operation on a current entry of the roaming list;

select an entry of the roaming list based in part on the measurement operation;

set a transmitter based on the selected entry of the roaming list; and

transmit an uplink signal to an access point at a time based on a slot start time and a random timing offset, and wherein the uplink signal is transmitted while at least a portion of a second signal is transmitted from a second node such that both the uplink signal and the second signal are received.

13. The node of claim 12, wherein the roaming list is received by the receiver during a prior transmission.

14. The node of claim 12, wherein the roaming list is received by the receiver at a particular prearranged frequency and at a particular prearranged gold code.

15. The node of claim 12, wherein the measurement operation comprises setting the receiver based on the current entry, measuring an RSSI metric at the receiver, and recording the RSSI metric;

and wherein the entry of the roaming list is selected based on a greatest RSSI metric.

16. The node of claim 12, wherein the receiver is further configured to:

order the roaming list into a priority list based on previous iterations of the measurement operation;

move the selected entry to a last entry of the priority list;

repeat the measurement operation for each entry in the priority list;

select a second entry of the priority list based in part on a second measurement operation; and

set the transmitter based on the selected second entry of the roaming list.

17. A system comprising:

a first access point comprising

a first downlink transmitter configured to transmit with a first transmit parameter;

a second access point comprising

a second downlink transmitter configured to transmit with a second transmit parameter; and

a node comprising

a processor,

a receiver operatively coupled to the processor and configured to

configure a roaming list comprising a plurality of entries, wherein a first entry comprises the first transmit parameter and a second entry comprises the second transmit parameter,

perform a measurement operation on a current entry of the roaming list,

select an entry of the roaming list based in part on a greatest RSSI metric,

set a transmitter based on the selected entry of the roaming list, and

transmit an uplink signal to an access point at a time based on a slot start time and a random timing offset, and wherein the uplink signal is transmitted while at least a portion of a second signal is transmitted from a second node such that both the uplink signal and the second signal are received.

18. The system of claim 17, wherein the roaming list is received by the receiver during a prior transmission.

19. The system of claim 17, wherein the roaming list is received by the receiver at a particular prearranged frequency and at a particular prearranged gold code.

20. The system of claim 17, wherein the receiver is further configured to:

order the roaming list into a priority list based on previous iterations of the measurement operation;

move the selected entry to a last entry of the priority list;

repeat the measurement operation for each entry in the priority list;

select a second entry of the priority list based in part on a second measurement operation; and

set the receiver based on the selected second entry of the roaming list.