Apparatus and method for setting a data rate in a wireless communication system

• US 7,062,687 B1
• Filed: 07/12/2000
• Issued: 06/13/2006
• Est. Priority Date: 07/12/1999
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Schott, Wolfgang, Gfeller, Fritz
• Primary Examiner(s): TU, CHRISTINE TRINH LE
• Application Number:
  US09/614,231
• Time in Patent Office: 2,162 Days
• Field of Search: 714/704, 714/706, 714/707, 714/708, 714/712, 714/713, 714/819, 714/821, 714/822, 714/43, 714/56, 714/46, 714/748, 377/39, 377/49, 377/94, 370/333, 379/58, 379/63, 379/350, 455/67.1, 455/67.3
• US Class Current: 714/704
• CPC Class Codes: H04L 1/0002 by adapting the transmission rate
• CPC Class Codes: H04L 1/20 using signal quality detector

Abstract

An apparatus and method for setting a transfer rate of information units in a variable data-rate transmission scheme for a wireless communication system is disclosed. For that, a total counter for counting a total number of received information units, an error counter for counting an error number of received invalid information units, a division unit for dividing the error number by the total number, and a decision unit for setting a transmission-rate parameter are utilizable. The division result is providable as a link-quality measure at an output of the division unit. This link-quality measure is comparable with at least one predefined value depending on the result of which, the transmission-rate parameter is setable.

Claims

1. An apparatus for setting a transmission-rate parameter for transmission of information units in a wireless communication system, comprising:

a total counter for counting a total number of received information units in a single received sequence of L-slot Pulse Position Modulation (L-PPM) information units;

an error counter for counting an error number of invalid received information units in the sequence of L-PPM information units;

a division unit for dividing said error number by said total number, the division result being providable as a link-quality measure at an output of said division unit, characterized in that said division unit is adapted to automatically perform binary divisions by 2 using a shift operation after n information units are received, where n is some integral power of 2; and

a decision unit for setting said transmission-rate parameter by comparing said link-quality measure with at least one predefined value and defining said transmission-rate parameter to assume a corresponding data rate.

2. Apparatus according to claim 1, wherein the link-quality measure or the transmission-rate parameter is sequentially updatable.

3. Apparatus according to claim 1, wherein the error number is maintained between at least two subsequent updates of the link-quality measure.

4. Apparatus of claim 1 further comprising a control unit which controls the total counter, the error counter, the division unit, and the decision unit.

5. Apparatus according to claim 1, wherein the division unit comprises the error counter.

6. Apparatus according to claim 1, wherein the decision unit comprises at least one comparator and a derivation unit for deriving from at least one output of said comparator the transmission-rate parameter.

7. Apparatus according to claim 1, wherein at least four predefined values are preloadable thresholds which correspond to a data rate of 4, 2, 1, 0.5 or 0.25 Mb/s, respectively.

8. An adaptive variable data-rate system for transmitting data over an infrared link comprising an apparatus according to claim 1.

9. An apparatus for setting a transmission-rate parameter for transmission of information units in a wireless communication system, comprising:

a total counter for counting a total number of received information units in a single received sequence of L-slot Pulse Position Modulation (L-PPM) information units;

an error counter for counting an error number of received invalid information units in the sequence of L-PPM information units;

a division unit for dividing said error number by said total number, the division result being providable as a link-quality measure at an output of said division unit; and

a decision unit for setting said transmission-rate parameter by comparing said link-quality measure with at least one predefined value and defining said transmission-rate parameter to assume a corresponding data rate,

wherein the link-quality measure is derivable iteratively increasing said total number after 2ⁿ*f counted information units, with n=0, 1,2, . . . and f a defined factor.

10. Apparatus according to claim 9, wherein the division is executable at a multiple of factor f automatically by a shift operation corresponding to n.

11. An apparatus for setting a transmission-rate parameter for transmission of information units in a wireless communication system, comprising:

a total counter for counting a total number of received information units in a single received sequence of L-slot Pulse Position Modulation (L-PPM) information units;

an error counter for counting an error number of received invalid information units in the sequence of L-PPM information units;

a division unit for dividing said error number by said total number, the division result being providable as a link-quality measure at an output of said division unit; and

a decision unit for setting said transmission-rate parameter by comparing said link-quality measure with at least one predefined value and defining said transmission-rate parameter to assume a corresponding data rate, wherein the division unit comprises storage cells having a shift control, or comprises a multiplexer having a static logic.

12. A method for setting a transmission-rate parameter for transmission of information units in a wireless communication system, comprising the steps of:

counting a total number of received information units in a single received sequence of L-slot Pulse Position Modulation (L-PPM) information units;

counting an error number of received invalid information units in said sequence of L-PPM information units;

dividing said error number by said total number and providing the division result as a link-quality measure;

comparing said link-quality measure with at least one predefined value; and

automatically setting said transmission-rate parameter depending on the result of the comparison.

13. Method according to claim 12, wherein the link-quality measure or the transmission-rate parameter is sequentially updated.

14. Method according to claim 12, wherein the information units are encoded by Pulse Position Modulation.

15. Method according to claim 12, wherein with the setting of the transmission-rate parameter, a data rate of information units is adapted to the link-quality measure.

16. Method according to claim 15, wherein the data rate depends on a repetition of information units.

17. Method according to claim 12, wherein said counting a total number, counting an error number, dividing, comparing and setting steps are carried out by means of a computer program.

18. A method as recited in claim 12, wherein said decision unit automatically sets the said transmissiion rate parameter.

19. A method for setting a transmission-rate parameter for transmission of information units in a wireless communication system, comprising the steps of:

counting a total number of received information units in a single received sequence of L-slot Pulse Position Modulation (L-PPM) information units;

counting an error number of received invalid information units in said sequence of L-PPM information units;

p1 dividing said error number by said total number and providing the division result as a link-quality measure;

comparing said link-quality measure with at least one predefined value; and

setting said transmission-rate parameter depending on the result of the comparison, wherein the link-quality measure is derived after receiving a number of information units that is a multiple of 2ⁿ, with n=0, 1, 2, . . . .

20. Computer readable program code means for causing a computer to effect a determination of a link-quality measure in order to set a transmission-rate parameter for transmission of information units in a wireless communication system, comprising the steps of:

counting a total number of received information units in a single received sequence of L-slot Pulse Position Modulation (L-PPM) information units;

counting an error number of received invalid information units in said sequence of L-PPM information units;

dividing said error number by said total number and providing the division result as a link-quality measure;

comparing said link-quality measure with at least one predefined value; and

automatically setting said transmission-rate parameter depending on the result of the comparison.