Communication system using ARQ

• US 7,561,893 B2
• Filed: 02/28/2003
• Issued: 07/14/2009
• Est. Priority Date: 04/10/2002
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Moulsley, Timothy J., Baker, Matthew P. J.
• Primary Examiner(s): Nguyen; Duc
• Assistant Examiner(s): PEREZ, ANGELICA
• Application Number:
  US10/510,260
• Publication Number:
  US 20050143114A1
• Time in Patent Office: 2,328 Days
• Field of Search: 455/522, 455/69, 370/318, 714/748
• US Class Current: 455/522
• 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 1/1858 Transmission or retransmission of more than one copy of acknowledgement message
• 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 52/325 Power control of control or pilot channels
• CPC Class Codes: H04W 52/36 with a discrete range or set of values, e.g. step size, ramping or offsets
• 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 communication system comprises a downlink data channel for the transmission of data packets from a primary station to a secondary station and two uplink control channels, a first channel for transmission of status signals to indicate the status of received data packets and a second channel for transmission of pilot information. In operation, on detection (402) of a data packet the secondary station increases (404) the transmission power of the second channel, thereby enabling the primary station to obtain a better estimate of uplink channel properties and hence increase the accuracy with which it can decode the status signal. The secondary station transmits (406) the status signal, typically either an acknowledgement (ACK) or negative acknowledgement (NACK), and decreases (408) the transmission power of the second control channel signal. The increase and decrease in power are not necessarily identical, for example as a result of the effects of power control.

Claims

1. A communication system having a downlink data channel for transmission of data packets from a primary station to a secondary station, a first uplink control channel for transmission of information relating to reception of data packets from the secondary station to the primary station, and a second uplink control channel for transmission of pilot information, the secondary station having receiving means for receiving a data packet and acknowledgement means for transmitting a status signal on the first uplink control channel to the primary station to indicate a status of a received data packet, wherein the secondary station comprises power control means for temporarily increasing a transmission power of at least a part of the second uplink control channel including the pilot information for a predetermined period during which the status signal is transmitted, and wherein the communication system further comprises an uplink data channel, a gain factor being defined as a ratio between the transmission power of the second uplink control channel and a transmission power of the uplink data channel, and means for adjusting the gain factor for a duration of a transmission power increase of the part of the second uplink control channel, thereby maintaining the transmission power of the uplink data channel at a similar level to that before the transmission power increase.

2. A primary station for use in a communication system having a downlink data channel for transmission of data packets from the primary station to a secondary station, a first uplink control channel for transmission of information relating to reception of data packets from the secondary station to the primary station, and a second uplink control channel for transmission of pilot information, wherein means are provided for receiving a status signal on the first uplink control channel indicating a status of a data packet transmitted to the secondary station, closed loop power control means are provided for controlling a power of the second uplink control channel, and means are provided for adjusting the operation of the power control means for a predetermined period around a time when transmission of the status signal by the secondary station is expected to take into account a temporary increase of a transmission power of at least the part of the second uplink control channel including pilot information, and wherein the communication system further comprises an uplink data channel, a gain factor being defined as a ratio between the transmission power of the second uplink control channel and a transmission power of the uplink data channel, and means for adjusting the gain factor for a duration of a transmission power increase of the part of the second uplink control channel, thereby maintaining the transmission power of the uplink data channel at a similar level to that before the transmission power increase.

3. The primary station as claimed in claim 2, further comprising means for signalling to the secondary station a magnitude of the transmission power increase which should be applied.

4. The primary station as claimed in claim 3, further comprising means for signalling a change in another parameter at the same time as a power offset is signalled.

5. The primary station as claimed in claim 4, wherein the other parameter is a number of repetitions of the status signal.

6. A secondary station for use in a communication system having a downlink data channel for transmission of data packets from a primary station to a secondary station, a first uplink control channel for transmission of information relating to reception of data packets from the secondary station to the primary station, and a second uplink control channel for transmission of pilot information, wherein receiving means are provided for receiving a data packet from the primary station and acknowledgement means are provided for transmitting a status signal on the first uplink control channel to the primary station to indicate the status of a received data packet, wherein power control means are provided for temporarily increasing a transmission power of at least a part of the second control channel including the pilot information for a predetermined period during which the status signal is transmitted, and wherein the communication system further comprises an uplink data channel, a gain factor being defined as a ratio between the transmission power of the second uplink control channel and a transmission power of the uplink data channel, and means for adjusting the gain factor for a duration of a transmission power increase of the part of the second uplink control channel, thereby maintaining the transmission power of the uplink data channel at a similar level to that before the transmission power increase.

7. The secondary station as claimed in claim 6, wherein an amount by which the transmission power is increased at a start of the predetermined period is different from an amount by which the transmission power is decreased at an end of the predetermined period.

8. The secondary station as claimed in claim 6, further comprising means for increasing the transmission power by different amounts depending on whether the status signal is an acknowledgement or a negative acknowledgement.

9. The secondary station as claimed in claim 6, further comprising means for increasing the transmission power by a first amount at a start of the predetermined period and by a second amount when a type of the status signal to be transmitted has been determined, the second amount depending on whether the status signal is an acknowledgement or a negative acknowledgement.

10. The secondary station as claimed in claim 6, further comprising means for resetting a timer on detection of an indication that a data packet has been transmitted to the secondary station, wherein the predetermined period lasts until the timer expires.

11. The secondary station as claimed in claim 6, further comprising means for communicating substantially simultaneously with a plurality of primary stations, for receiving power control commands from each of the primary stations and for receiving a data packet from any one of the primary stations, and means for setting the power of uplink transmissions depending on power control commands received from the primary station which transmitted the packet for the duration of the predetermined period.

12. A method of operating a communication system having a downlink data channel for transmission of data packets from a primary station to a secondary station, a first uplink control channel for transmission of information relating to reception of data packets from the secondary station to the primary station, and a second uplink control channel for transmission of pilot information, the method comprising the secondary station receiving a data packet and transmitting a status signal on the first uplink control channel to the primary station to indicate a status of a received data packet, wherein the secondary station temporarily increases a transmission power of at least the part of the second uplink control channel including the pilot information for a predetermined period during which the status signal is transmitted, and wherein the communication system further comprises an uplink data channel, a gain factor being defined as a ratio between the transmission power of the second uplink control channel and a transmission power of the uplink data channel, and means for adjusting the gain factor for a duration of a transmission power increase of the part of the second uplink control channel, thereby maintaining the transmission power of the uplink data channel at a similar level to that before the transmission power increase.