Adaptive frame durations for time-hopped impulse radio systems

• US 20060245471A1
• Filed: 08/08/2005
• Published: 11/02/2006
• Est. Priority Date: 01/04/2005
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Molisch, Andreas F.
• Granted Patent: US 7,403,746 B2
• Time in Patent Office: Days
• US Class Current: 375/138
• CPC Class Codes: G01S 11/02 using radio waves G01S19/00 takes precedence
• CPC Class Codes: H04B 1/71632 Signal aspects H04B1/7172 and H04B1/7176 take precedence
• CPC Class Codes: H04B 1/719 Interference-related aspects
• CPC Class Codes: H04B 2001/6908 using time hopping
• CPC Class Codes: H04L 1/0007 by modifying the frame length
• CPC Class Codes: H04L 1/0019 in which mode-switching is based on a statistical approach
• CPC Class Codes: H04L 25/0202 Channel estimation

Abstract

A method determines a duration of a frame in an impulse radio system for radio ranging. Channel state information of a channel between two transceivers is estimated periodically. A signal to noise and interference ratio is also estimated periodically. The frame duration of the frame is then determined according to the channel state information and the signal to noise and interference ratio.

Claims

1. A method for determining a duration of a frame in an impulse radio system, comprising:

determining a frame duration of a radio signal according to channel state information;

transmitting frames according to the frame duration from a transmitter to a receiver as pulses; and

estimating a time of arrival of the pulses in the receiver to determine a distance between the transmitter and the receiver.

2. The method of claim 1, in which the transmitter periodically estimates the channel state information.

3. The method of claim 2, in which the frame duration is longer for non-coherent receivers than for coherent receivers.

4. The method of claim 1, in which the radio signal uses a sequence of pulses, and further comprising:

increasing the frame duration by increasing a spacing of the pulses farther apart in time.

5. The method of claim 1, in which the radio signal is a spread spectrum radio signal.

6. The method of claim 4, the pulses have a polarity of +1, −

1, and 0.

7. The method of claim 4, the pulses have a polarity of +1, and −

1.

8. The method of claim 1, where the radio signal is a time-hopped signal, i.e., the position of the pulse within a frame is determined by a pseudorandom sequence.

9. The method of claim 1, in which the frame duration is set identically by a master device for all slave devices in the radio system.

10. The method of claim 1, in which the frame duration is set individually by a master device for each slave device in the radio system.

11. The method of claim 1, in which two devices negotiate the frame duration between themselves.

12. The method of claim 1, in which the receiver periodically estimates the channel state information of a channel.

12-1. A method for determining a duration of a frame in an impulse radio system, comprising:

determining a frame duration of a radio signal according to channel state information and a structure of a receiver;

transmitting frames according to the frame duration from a transmitter to the receiver as pulses; and

estimating a time of arrival of the pulses in the receiver to determine a distance between the transmitter and the receiver.

13. A method for determining a duration of a frame in an impulse radio system, comprising:

determining a frame duration of a radio signal according to a structure of a receiver;

transmitting frames according to the frame duration from a transmitter to the receiver as pulses; and

estimating a time of arrival of the pulses in the receiver to determine a distance between the transmitter and the receiver.