Apparatus and method for controlling transmitted power in a radio network

• US 5,465,399 A
• Filed: 09/16/1994
• Issued: 11/07/1995
• Est. Priority Date: 08/19/1992
• Status: Expired due to Term

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Oberholtzer, John C., Nitardy, John H.
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): VO, NGUYEN THANH
• Application Number:
  US08/307,473
• Time in Patent Office: 417 Days
• Field of Search: 455/54.2, 455/69, 455/9, 455/10, 455/49.1, 455/52.1, 455/51.1, 455/34.1, 455/186.1, 455/127, 455/67.1, 455/115, 455/82, 455/68, 455/50.1, 455/63, 455/70, 455/88 , 455/226.2, 455/226.3, 455/58.1, 455/54.1
• US Class Current: 455/69
• CPC Class Codes: H04W 52/228 using past power values or information
• CPC Class Codes: H04W 52/283 Power depending on the position of the mobile
• CPC Class Codes: H04W 52/288 taking into account the usage mode, e.g. hands-free, data transmission, telephone

Abstract

An adaptive power control used on a radio network and a method for adaptively controlling the transmit power level of member stations on the network. An exemplary network (12) includes a plurality of member stations (10a through 10f) between which radio signal propagation conditions are subject to change. Each member station includes a transceiver (21) having a transmitter (26) and a receiver (28) section. The transmit power level of the transmitter is controlled by a variable gain circuit (48) in response to a variable gain signal produced by a control (34). A member station uses a transmit power level determined by reference to a database in which signal-to-noise ratio (SNR) data defining the quality of each communication link and the transmit power levels last used for communication between each pair of member stations of the network are stored. If a response to a transmission in an initial frame is not received in the next frame, a controlling member station (server) incrementally increases its transmit power level by P_D in successive frames, until either a response is received or the member station has failed to respond to a transmission at a maximum transmit power level, P_max. If the response indicates that the signal is received with an SNR in excess of a predetermined margin, the server reduces its transmit power level to ensure that the minimum transmit power is used.

Claims

1. An adaptive power level radio network, comprising:

a plurality of member stations, one of said plurality of member stations becoming a controller station by initiating a communication with the other member stations on the network, said plurality of member stations each including;

(a) a transmitter having a selectively variable transmit power level, the transmitter of the controller station transmitting a radio signal at a predefined power level;

(b) a receiver; and

(c) control means, connected to the receiver and to the transmitter, for;

(i) controlling the transmit power level of the transmitter;

(ii) designating one of said plurality of member stations as a selected station by determining which of said plurality of member stations had the poorest reception based on prior communications between said one of said plurality of member stations and the other member stations of the network; and

(iii) adjusting the transmit power level of the controller station, in response to respondent signal received by the controller station from the transmitter of said selected station, said respondent signal indicating whether said selected, member station has received a transmission from the controller station that was transmitted at the predefined transmit power level, the control means of the controller station responding to a failure to receive the respondent signal from said selected station, by incrementally increasing the transmit power level of the transmitter in the controller station, to establish communications with stud selected station.

2. The adaptive power level radio network of claim 1, wherein said plurality of member stations each further comprises means for determining a reception quality for the reception of the radio signals by the receiver, said control means reporting the reception quality of the radio signal initially received from the controller station in the respondent signal.

3. The adaptive power level radio network of claim 2, wherein the control means reduce the transmit power level of the transmitter in the controller station, if the reception quality indicated by the respondent signal exceeds a predefined value.

4. The adaptive power level radio network of claim 2, wherein the control means comprise a processing unit;

and associated memory means for storing instructions that determine how the processing unit controls the transmit power level of the transmitter in the controller station, in response to the respondent signal.

5. The adaptive power level radio network of claim 4, wherein the memory means also store data that include the reception quality and transmit power levels used by said plurality of member stations in the network, said data being compiled from the respondent signals from at least three other member stations of said plurality of member stations, the control means using the data to designate said selected station and adjust the predefined transmit power level for the transmitter of said controller station.

6. The adaptive power level radio network of claim 2, wherein said plurality of member stations identify themselves in the respondent signal with an identification code, the control means of said plurality of member stations encoding the identification code, the reception quality, and a transmit power level in the respondent signal.

7. The adaptive power level radio network of claim 1, wherein if the control means of one of the plurality of member stations transmits a break-in signal to interrupt communication between other of the plurality of member stations in the network, the control means of the controller station terminate any transmission then in progress, and said member station transmitting the break-in signal becomes the controller station.

8. The adaptive power level radio network of claim 1, wherein the control means designates another one of said plurality of member stations as a selected station when the transmit power level of the transmitter in the controller station has reached a maximum and said respondent signal has not been revived.

9. The adaptive power level radio network of claim 1, wherein the control means designates said selected station as inactive from the network when the transmit power level of the transmitter in the controller station has reached a maximum and said respondent signal has not been received.

10. The adaptive power level radio network of claim 1, wherein signals transmitted from one of said plurality of member stations of the network to another comprise frames of a predefined duration, and wherein the control means determine the contents of each frame, said frames each comprising a control portion that conveys control signals and a communication portion that conveys communication signals.

11. An adaptive power level radio network, comprising:

a plurality of member stations, one of said plurality of member stations becoming a controller station by initiating a communication with another member station on the network, said plurality of member stations each including;

(a) a transmitter having a selectively variable transmit power level, the transmitter of the controller station transmitting a radio signal at a predefined power level;

(b) a receiver;

(c) control means, connected to the receiver and to the transmitter, for controlling the tramsmit power level of the transmitter and adjusting the transmit power level of the controller station in response to a respondent signal received by the controller station from the transmitter of said another member station with which the controller station is communicating, said respondent signal indicating whether said another member station has received a transmission from the controller station that was transmitted at the predefined transmit power level, the control means of the controller station responding to a failure to receive the respondent signal from said another member station, by incrementally increasing the transmit power level of the transmitter in the controller station, to establish communications with said another member station, the control means including;

(i) a processing unit; and

(ii) associated memory means for storing;

(1) instructions that determine how the processing unit controls the transmit power level of the transmitter in the controller station, in response to the respondent signal;

(2) data and that include reception quality and the transmit power levels used by said plurality of transmitters of other member stations in the network, said data being compiled from the respondent signals from each of the other member stations, the control means using the data to determine the predefined transmit power level for the transmitter of said controller station as a function of the poorest reception quality for all of the member stations stored in the data, for insuring communication between said controller station and the member station that reported the poorest reception quality in its respondent signal; and

(d) means for determining the reception quality for the reception of the radio signals by the receiver, said control means reporting the reception quality of the radio signal initially received from the controller station in the respondent signal;

wherein the control means operates in a plurality of modes in controlling the transmitter with which it is connected, including;

(i) a passive monitor mode, entered when the network is being initialized, before a station becomes one of the plurality of member stations of the network and before the data are stored in the memory means;

(ii) an active mode, wherein the station is one of the plurality of member stations of the network, its control means have identified other member stations of the network, and at least some of the data have been stored in the memory means; and

(iii) a controlling mode, wherein the station is serving as said controller station and is in communication with at least one of the plurality of member stations of the network, and data for all other of the plurality of member stations are stored in the memory means of the controller station.

12. The adaptive power level radio network of claim 11, wherein the means for determining the quality of reception comprise a signal-to-noise power ratio monitor.

13. An adaptive power level radio network, comprising:

a plurality of member stations, each of which include;

transceiver means, including a transmitter portion and a receiver portion, for selectively transmitting and receiving radio signals, respectively, the transceiver means having a selectively variable transmit power level;

data storage means, for storing data indicating a relative quality of a communication link between said member station and at least one other member station of the network; and

control means, connected to the transceiver means and the data storage means, for controlling the transceiver means, causing the transmit power level of the transceiver means to increase by a predefined increment if a respondent signal is not received from a designated member station in the network in response to a transmission of a radio signal from said transceiver means, wherein based upon the relative quality of each communication link, as indicated by the data within the data storage means, the control means;

(a) determine a minimum transmit power level at which the transceiver means transmits to achieve a communication link with the designated member station; and

(b) determine the designated member station as the station having the poorest quality communication link relative to said member station.

14. The adaptive power level radio network of claim 13, wherein said plurality of member stations each further includes means for determining a signal-to-noise ratio of the radio signals received from others of said plurality of member stations;

and wherein the data stored in the data storage means include the signal-to-noise ratio reported by at least some of the other member stations, the control means selecting as the designated member station one of the plurality of member stations intended to receive a communication, where said one of the plurality of member stations that has a lowest signal-to-noise ratio of all of the plurality of member stations for which data are stored in the data storage means.

15. The adaptive power level radio network of claim 13, wherein the control means cause the transceiver means of a member station initiating a communication to poll other member stations of the network by including a specific request for a response indicating the relative quality of the received radio signal.

16. The adaptive power level radio network of claim 13, wherein the transceiver means transmits a plurality of frames during each transmission, a frame that is initially transmitted including at least a synchronization signal and a control block portion containing control signals that are used by the control means of any of the plurality of member stations receiving the transmission.

17. The adaptive power level radio network of claim 16, wherein the control block portion comprises a plurality of operational codes that define different operating conditions of the network to which the control means of the plurality of member stations receiving a transmission including said plurality of operational codes respond during:

(a) initiation of the network; and

(b) when one of the plurality of member stations is establishing communications with others of the plurality of member stations of the network.

18. The adaptive power level radio network of claim 17, wherein one of the plurality of member stations is a controller station which controls the network, the control means of the controller station respond to a break-in operational code received from one of the plurality of member stations, by yielding control of the network to said member station from which the break-in operational code is received.

19. A method for adaptively controlling a transmit power level of a radio signal transmitted by a transmitter in a member station of a network including a plurality of member stations, comprising the steps of:

(a) accumulating and storing data, said data defining quality of prior communication between said member station and other member stations in the network;

(b) identifying a specific member station included in the network as having the poorest quality communication link, based on said stored data;

(c) transmitting a polling radio signal at a predefined transmit power level, the polling radio signal serving to request a respondent signal from said specific member station;

(d) continuing to transmit a message at the predefined transmit power level, if said specific member station responds with the respondent signal, for indicating that the polling radio signal has been received and that an acceptable communication link has been established at a minimum transmit power level;

(e) increasing the transmit power level by a predefined increment, if the specific member station does not respond with the respondent signal; and

(f) repeating step (e) for successive subsequent radio transmissions before again transmitting the message, until said specific member station responds with the respondent signal or until a predefined maximum transmit power level is achieved, whichever occurs first, for attempting to establish an effective communications link at the minimum transmit power level before transmitting the message.

20. The method of claim 19, further comprising the steps of:

determining a reception quality for radio transmissions received from other member stations of the network; and

including the reception quality with which the radio signal polling the other member station is received in the respondent signal transmitted by the other station.

21. The method of claim 20, further comprising the step of decreasing the transmit power level, if the reception quality included in the respondent signal exceeds a predefined margin.

22. The method of claim 21, further comprising the step of incrementally reducing the transmit power level in subsequent radio transmissions until the reception quality reported by any other member station is less than or equal to the predefined margin.

23. The method of claim 19, wherein the polling radio signal comprises at least a synchronization portion and a control block portion, the synchronization portion being used to synchronize radio transmissions of other member stations, and the control block portion including a request for the respondent signal that is directed to said specific member station in the network.

24. The method of claim 23, wherein the polling radio signal and a subsequent radio signal transmitted by one of the plurality of member stations each comprise a plurality of frames.

25. The method of claim 23, wherein the control block comprise operational codes that define an operational status of the network and determine an operating mode for specific member stations from a plurality of operating modes of the network.

26. The method of claim 25, further comprising the steps of accumulating and storing data at each member station, said data defining a quality of the communication link between said member station and other member stations in the network.

27. A method for adaptively controlling a transmit power level of a radio signal transmitted by a transmitter in a member station of a network, comprising the steps of:

(a) transmitting a polling radio signal at a predefined transmit power level, the polling radio signal serving to request a respondent signal from at least one other member station included in the network, to establish a communication link, the polling radio signal including at least a synchronization portion and a control block portion, the synchronization portion being used to synchronize radio transmissions of other member stations, and the control block portion including a request for the respondent signal that is directed to a specific member station in the network and operational codes that define the status of the network and determine an operating mode for specific member stations;

(b) continuing to transmit a message at the predefined transmit power level, if the other member station responds with the respondent signal, for indicating that the polling radio signal has been received and that an acceptable communication link has been established at a minimum transmit power level;

(c) increasing the transmit power level by a predefined increment, if the other member station does not respond with the respondent signal;

(d) repeating step (c) for successive subsequent radio transmissions before transmitting the message, until the other member station responds with the respondent signal or until a predefined maximum transmit power level is achieved, whichever occurs first, for attempting to establish an effective communications link at the minimum transmit power level before transmitting the message; and

(e) accumulating and storing data at each member station, said data defining a quality of the communication link between said member station and other member stations in the network;

wherein each member station operates in one of a plurality of modes, including;

(i) a passive mode entered before the network is initialized and before becoming a member station of the network;

(ii) an active monitor mode, wherein the member station is part of the network, has identified all other member stations in the network, is ready to respond to the polling radio signal from another member station, and has stored the data defining the quality of the communication link between itself and at least some of the other member stations in the network; and

(iii) a controller mode, wherein the member station is part of the network, has identified all other member stations in the network, and is initiating or attempting to initiate communication with at least one other member station in the network, said member station initiating or attempting to initiate communication with said at least one other member station then comprising a controlling station.

28. The method of claim 27, further comprising the steps of identifying which of the plurality of member stations has the poorest quality communication link, based on the data stored, and initially transmitting the polling radio signal to said member station having the poorest quality communication link.

29. The method of claim 28, wherein the member station having the poorest quality communication link transmits a respondent signal that includes an indication of a transmit power level and the reception quality of the polling radio signal, which are stored as data by the plurality of member stations included in the network.

30. The method of claim 29, wherein the reception quality comprises a signal-to-noise ratio, and wherein the controlling station operating in the controller mode reduces its transmit power level to achieve a minimum acceptable signal-to-noise ratio for radio signals received by another member station.

31. An adaptive power level radio network, comprising:

a plurality of member stations, one of said plurality of member stations becoming a controller station by initiating a communication with another member station on the network, said plurality of member stations each including;

(a) a transmitter having a selectively variable transmit power level, the transmitter of the controller station transmitting a radio signal at a predefined power level;

(b) a receiver; and

(c) control means, connected to the receiver and to the transmitter, for controlling the transmit power level of the transmitter and adjusting the transmit power level of the controller station in response to a respondent signal received by the controller station from the transmitter of said another member station with which the controller station is communicating, said respondent signal indicating whether said another member station has received a transmission from the controller station that was transmitted at the predefined transmit power level, the control means of the controller station responding to a failure to receive the respondent signal from said another member station, by incrementally increasing the transmit power level of the transmitter in the controller station, to establish communications with said another member station, said control means including memory for storing data and operating in a plurality of modes in controlling the transmitter with which it is connected, including;

(i) a passive monitor mode, entered when the network is being initialized, before a station becomes one of the plurality of member stations of the network;

(ii) an active mode, wherein the station is one of the plurality of member stations of the network, its control means have identified other member stations of the network, and the station has stored at least some data indicative of a reception quality for transmissions between itself and the other member stations of the network in the memory of its control means; and

(iii) a controlling mode, wherein the member station is serving as said controller station and is in communication with at least one of the plurality of member stations of the network, and data indicative of the reception quality for transmissions between itself and the other member stations of the network are stored in the memory of the controller station.

32. The adaptive power level radio network of claim 31, wherein the control means comprise a signal-to-noise power ratio monitor for determining the quality of reception.

33. A method for adaptively controlling a transmit power level of a radio signal transmitted by a transmitter in a member station of a network, comprising the steps of:

(a) transmitting a polling radio signal at a predefined transmit power level, the polling radio signal serving to request a respondent signal from at least one other member station included in the network, to establish a communication link;

(b) continuing to transmit a message at the predefined transmit power level, if the other member station responds with the respondent signal, for indicating that an acceptable communication link has been established;

(c) increasing the transmit power level by a predefined increment, if the other member station does not respond with the respondent signal; and

(d) repeating step (c) for successive subsequent radio transmissions before again transmitting the message, until the other member station responds with the respondent signal or until a predefined maximum transmit power level is achieved, whichever occurs first, for attempting to establish an effective communications link at a minimum transmit power level before transmitting the message, each member station of the network operating in one of a plurality of modes, including;

(i) a passive mode entered before the network is initialized and before becoming a member station of the network;

(ii) an active monitor mode, wherein the member station is part of the network, has identified all other member stations in the network, is ready to respond to the polling radio signal from another member station, and has stored data defining quality of the communication link between itself and at least some of the other member stations in the network; and

(iii) a controller mode, wherein the member station is part of the network, has identified all other member stations in the network, and is initiating or attempting to initiate communication with at least one other member station in the network, said member station then comprising a controlling station.

34. The method of claim 33, further comprising the steps of identifying which of the plurality of member stations has the poorest quality communication link, based on the data stored, and initially transmitting the polling radio signal to said member station having the poorest quality communication link.

35. The method of claim 34, wherein the member station having the poorest quality communication link transmits a respondent signal that includes an indication of a transmit power level and the reception quality of the polling radio signal, which are stored as data by the plurality of member stations comprising the network.

36. The method of claim 35, wherein the reception quality comprises a signal-to-noise ratio, and wherein the controlling station operating in the controller mode reduces its transmit power level to achieve a minimum acceptable signal-to-noise ratio for radio signals received by another member station.