Interfrequency measurement

• US 6,507,570 B1
• Filed: 05/14/1999
• Issued: 01/14/2003
• Est. Priority Date: 05/15/1998
• Status: Expired due to Fees

• Current Assignee: Nokia Mobile Phones UK Limited (Nokia Corporation)
• Original Assignee: Nokia Mobile Phones UK Limited (Nokia Corporation)
• Inventors: Holma, Harri, Toskala, Antti
• Primary Examiner(s): Bost, Dwayne
• Assistant Examiner(s): Trinh, Sonny
• Application Number:
  US09/312,179
• Time in Patent Office: 1,341 Days
• Field of Search: 370/330, 370/332, 370/333, 370/335, 370/342, 370/328, 370/329, 370/318, 455/436, 455/437, 455/438, 455/444, 455/447, 455/24, 455/525, 455/134, 455/135, 714/704
• US Class Current: 370/333
• CPC Class Codes: H04L 1/0056 Systems characterized by the type of code used H04L1/08 takes precedence
• CPC Class Codes: H04W 36/00837 Determination of triggering parameters for hand-off
• CPC Class Codes: H04W 36/0085 Hand-off measurements
• CPC Class Codes: H04W 72/54 based on quality criteria

Abstract

A radio telephone for communicating in a spreadspectrum communication system having a plurality of radio channels of different frequencies; the radio telephone comprising communication means for establishing over one of said radio channels a communication link over which is communicated data and associated error correction data; a receiver operable to alternatively receive for a period a radio channel other than the established channel and processing means for measuring the radio signal characteristics of the other channel; the processing means being operable to use error correction data received over the established communication link to calculate the contents of the established communication link data of the radio channel signal during the period.

Claims

1. A radio telephone for communicating in a spreadspectrum communication system having a plurality of radio channels of different frequencies, the radio telephone comprising:

communication means for establishing over one of said radio channels a communication link over which is communicated data and associated error correction data;

a receiver operable to alternatively receive for a period a radio channel other than the established channel, wherein the communication means is adapted to requesting increased power from the spreadspectrum communication system at a predetermined interval before the receiver receives the other radio channel; and

processing means for measuring the radio signal characteristics of the other channel;

the processing means being operable to use error correction data received over the established communication link to calculate the contents of the established communication link data of the radio channel signal during the period.

2. A radio telephone according to claim 1 wherein the processing means measures the received signal strength.

3. A radio telephone according to claim 1 wherein the communication means is responsive to a control signal from the processing means for requesting the communication system to increase power a predetermined interval before the receiver receives the other radio channel.

4. A radio telephone according to claim 1 wherein if the signal characteristics of the other radio channel complies with at least one predetermined criterion a communication link over the other radio channel is established.

5. A method of using a radio telephone for measuring a radio channel in a spreadspectrum communication system having a plurality of radio channels of different frequencies;

the method comprising;

establishing a communication link over one of said radio channels over which is communicated data and associated error correction data;

alternatively receiving for a period a radio channel other than the established channel;

requesting an increase in power of the established channel at a predetermined interval before receiving the other radio channel; and

measuring the radio characteristics of the other channel using error correction data received over the established communication link to calculate the contents of the established communication link data of the radio channel signal during the period.

6. A method according to claim 5 wherein the received signal strength is measured.

7. A method according to claim 5 wherein if the signal characteristics of the other radio channel complies with at least one predetermined criterion a communication link over the other radio channel is established.

8. A radio telephone for communicating in a spreadspectrum communication system, the radio telephone comprising:

a receiver for receiving a first signal including data and error correction information; and

a processor for requesting an increase in power of the first signal from the communication system before the receiver receives a second signal, the processor being operable for using the error correction information to recover data from the first signal for a time during which the receiver receives the second signal.

9. The radio telephone of claim 8, further comprising a signal measuring device for measuring the signal characteristics of the first and second signals.

10. The radio telephone of claim 9, wherein a handoff to the second signal is performed if the signal characteristics of the second signal comply with a predetermined criteria.

11. The radio telephone of claim 8, wherein a duration of the time during which the receiver receives the second signal is determined from a channel coding rate of the first signal.

12. The radio telephone of claim 8, wherein a duration of the time during which the receiver receives the second signal is determined from a signal loss of the first signal for the duration.