Radio communication system

• US 20030099211A1
• Filed: 09/23/2002
• Published: 05/29/2003
• Est. Priority Date: 10/19/2001
• Status: Active Grant

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Baker, Matthew P.J., Moulsley, Timothy J., Hunt, Bernard
• Granted Patent: US 7,379,434 B2
• Time in Patent Office: Days
• US Class Current: 370/328
• CPC Class Codes: H04L 1/1692 Physical properties of the supervisory signal, e.g. acknowledgement by energy bursts
• CPC Class Codes: H04L 1/1809 Selective-repeat protocols
• CPC Class Codes: H04L 2001/125 Arrangements for preventing errors in the return channel
• CPC Class Codes: H04W 52/286 during data packet transmission, e.g. high speed packet access [HSPA]
• CPC Class Codes: H04W 52/44 in connection with interruption of transmission
• CPC Class Codes: H04W 52/48 during retransmission after error or non-acknowledgment
• CPC Class Codes: H04W 52/50 at the moment of starting communication in a multiple access environment

Abstract

A radio communication system comprises a communication channel for the transmission of data packets from a primary station (100) to a secondary station (110). In response to receipt of a data packet, the secondary station transmits an acknowledgement signal to the primary station indicating the status of the received data packet. The signal is selected from a set of at least two available signal types (for example positive and negative acknowledgements, ACK and NACK), and the power at which it is transmitted depends on the type of the signal.

In one embodiment NACKs are transmitted at a higher power than ACKs, thereby reducing the chance of the primary station misinterpreting a NACK as an ACK. In another embodiment a REVERT signal is used to request retransmission of a previous packet. The REVERT signal may be identical to the NACK signal but transmitted at a higher power.

Claims

1. A radio communication system having a communication channel for the transmission of data packets from a primary station to a secondary station, the secondary station having receiving means for receiving a data packet and acknowledgement means for transmitting a signal to the primary station to indicate the status of a received data packet, which signal is selected from a set of at least two available signal types, wherein the acknowledgement means is arranged to select the power level at which the signal is transmitted depending on its type.

2. A system as claimed in claim 1, characterised in that the available signal types include signals indicating positive and negative acknowledgements.

3. A system as claimed in claim 2, characterised in that the available signal types further include a revert signal indicating a request for retransmission of a packet received before the packet just received.

4. A system as claimed in claim 3, characterised in that the revert signal is identical to the negative acknowledgement signal but is transmitted at a higher power.

5. A primary station for use in a radio communication system having a communication channel for the transmission of data packets from the primary station to a secondary station, wherein means are provided for transmitting a data packet to the secondary station and for receiving a signal from the secondary station to indicate the status of a received data packet, which signal is selected from a set of at least two available signal types, and wherein means are provided for determining the type of the received signal depending on its received power level.

6. A primary station for use in a radio communication system having a communication channel for the transmission of data packets from the primary station to a secondary station, wherein means are provided for transmitting a data packet to the secondary station and for receiving a signal from the secondary station to indicate the status of a received data packet, which signal is selected from a set of at least two available signal types, and wherein means are provided for signalling to the secondary station an indication of how the power level at which the secondary station transmits the signal depends on the type of the signal.

7. A primary station as claimed in claim 6, characterised in that means are provided for determining the type of the received signal depending on its received power level.

8. A primary station as claimed in claim 6, characterised in that the indication comprises an instruction to the secondary station to transmit at least two types of signals at different powers.

9. A primary station as claimed in claim 6, characterised in that the indication informs the secondary station of the transmission power that it should use for at least one of the available signal types.

10. A primary station as claimed in claim 6, characterised in that the indication informs the secondary station of a required power difference between two different types of signals.

11. A secondary station for use in a radio communication system having a communication channel for the transmission of data packets from a primary station to the secondary station, wherein receiving means are provided for receiving a data packet from the primary station and acknowledgement means are provided for transmitting a signal to the primary station to indicate the status of a received data packet, which signal is selected from a set of at least two available signal types, wherein the acknowledgement means is arranged to select the power level at which the signal is transmitted depending on its type.

12. A secondary station as claimed in claim 11, characterised in that the signal types include signals indicating positive and negative acknowledgements and in that the acknowledgement means transmits negative acknowledgements at a higher power than positive acknowledgements.

13. A secondary station as claimed in claim 12, characterised in that means are provided for determining the power difference between acknowledgements with reference to a time-averaged ratio of different signal types transmitted.

14. A secondary station as claimed in claim 13, characterised in that the acknowledgement means only transmits negative acknowledgements at a higher power than positive acknowledgements if a time-averaged ratio of positive acknowledgements to negative acknowledgements is greater than a predetermined value.

15. A secondary station as claimed in claim 11, characterised in that the available signal types include signals conveying information relating to prevailing radio conditions other that the status of the received data packet.

16. A method of operating a radio communication system having a communication channel for the transmission of data packets from a primary station to a secondary station, the method comprising the secondary station receiving a data packet and transmitting an acknowledgement signal to the primary station to indicate the status of a received data packet, which signal is selected from a set of at least two available signal types, the method comprising selecting the power level at which the signal is transmitted depending on its type.