Wireless Audio Transmission System and Method

• US 20080212582A1
• Filed: 04/05/2004
• Published: 09/04/2008
• Est. Priority Date: 04/05/2004
• Status: Active Grant

• Current Assignee: Wireless Audio IP BV (Microchip Technology Incorporated)
• Original Assignee: Wireless Audio IP BV (Microchip Technology Incorporated)
• Inventors: Zwart, Willem, Schutten, Robert Niels, Lansbergen, Robertus Cornelis Wilhelmus, Coenen, Maarten, van Leeuwen, Johannes Cornelis Hendrikus, Moelker, Dignus-Jan
• Granted Patent: US 8,989,171 B2
• Time in Patent Office: Days
• US Class Current: 370/390
• CPC Class Codes: H04L 1/1692 Physical properties of the supervisory signal, e.g. acknowledgement by energy bursts
• CPC Class Codes: H04L 2001/0093 Point-to-multipoint
• CPC Class Codes: H04W 28/04 Error control
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames

Abstract

A system and method transmit a data stream from a source to a destination over a communication channel. A transmitter includes devices for processing inputs to assemble data packets for the data stream, and a multiplexer for assembling a data frame to be transmitted over the communication channel, in which each data frame has at least one fixed slot. The multiplexer sets at least one freely allocatable time slot in each data frame. Retransmission control devices connected to the multiplexer retransmit a specific data packet which is not properly received by the destination, using one of the freely allocatable slots.

Claims

1-30. -30. (canceled)

31. A method for transmitting at least one data stream from a source to at least one destination over a communication channel, the at least one data stream comprising a sequence of a plurality of data packets, the data stream being transmitted over the communication channel using a signal comprising data frames according to a protocol, in which each data frame has at least one fixed slot, in which each data frame further comprises at least one freely allocatable slot, in which a specific data packet, which is not properly received by the at least one destination, is retransmitted from the source using one of the at least one freely allocatable slot, wherein a data packet is transmitted uncompressed in the first transmission, and compressed in at least one of the retransmissions.

32. The method according to claim 31, in which the specific data packet for a specific data stream is retransmitted in the fixed slot of that specific data stream in a next data frame.

33. The method according to claim 31, in which the data frame comprises a down-link part and an up-link part, each having at least one fixed slot and at least one freely allocatable slot.

34. The method according to claim 31, in which a data packet has a predefined duration, the predefined duration being small compared to non-transmitting gaps of possible interfering sources.

35. The method according to claim 34, further comprising the detection of the non-transmitting gaps by carrier sense/detect techniques, and the synchronization of the data stream transmission to the detected non-transmitting gaps.

36. The method according to claim 31, further comprising receiving acknowledgement of a received data packet from the at least one destination, and retransmitting a not properly received data packet within the same data frame.

37. The method according to claim 31, in which each data frame comprises N fixed slots with a single negative acknowledge sub-slot following each of the N fixed slots, and each of the freely allocatable slots comprises N negative acknowledge sub-slots following the freely allocatable slot for indicating in which of the N fixed slots a packet was not received.

38. The method according to claim 36, in which the acknowledgment comprises a pseudo-noise code.

39. The method according to claim 31, in which at least one freely allocatable slot is allocated to transmit a control data message.

40. The method according to claim 39, in which a back-off mechanism is used for transmitting the control data message for multiple access.

41. The method according to claim 31, in which antenna and/or frequency diversity is applied.

42. The method according to claim 31, further comprising:

converting received data packets in an audio signal,

replacing a missing data packet by an earlier received data packet, and

smoothing the transition between the earlier received data packet and the replaced data packet.

43. The method according to claim 42, in which the smoothing is applied using a raised cosine filter function.

44. The method according to claim 31, further comprising scrambling a retransmitted data packet before retransmission using a pseudo-randomly varying scrambling technique, descrambling the retransmitted data packet upon reception.

45. The method according to claim 44, further comprising integrating multiple retransmitted data packets.

46. The method according to claim 31, in which the source increases its transmission power upon determination that a data packet is not properly received by the destination.

47. The method according to claim 46, in which the source compares the received signal strength to a threshold value, and decreases its transmission power by a predefined step if the threshold value is exceeded, and increases its transmission power by a predefined step otherwise.

48. The method according to claim 47, in which the threshold value is adaptively controlled by an outer control loop.

49. The method according to claim 31, in which a data packet comprises:

a preamble, and/or

a header, and/or

at least one packet of control message data, and/or

at least one packet of application data from at least one input.

50. A transmitter arrangement (20) for use in a system for transmitting at least one data stream from a source (10) to at least one destination (12) over a communication channel, the transmitter arrangement (20) comprising input processing means (21 . . . 23;

26, 27) for assembling data packets for each of the at least one data stream, and a multiplexer (29) arranged to receive data packets for each of the at least one data stream and to assemble a data frame to be transmitted over the communication channel, in which each data frame has at least one fixed slot, in which the multiplexer (29) is further arranged to provide at least one freely allocatable slot in each data frame, and in that the transmitter arrangement (20) further comprises retransmission control means (25;

28) connected to the multiplexer (29) and arranged to retransmit a specific data packet, which is not properly received by the at least one destination, using one of the at least one freely allocatable slot, wherein the transmitter arrangement (20) further comprises a compressor (24) connected to the retransmission control means (25;

28) to allow to transmit a data packet uncompressed in the first transmission, and compressed in at least one of the retransmissions.

51. The transmitter arrangement (20) according to claim 50, in which the multiplexer (29) and/or retransmission control means (25;

28) are further arranged to execute a method in which the specific data packet for a specific data stream is retransmitted in the fixed slot of that specific data stream in a next data frame.

52. The transmitter arrangement (20) according to claim 50, further comprising a scrambler (31) for scrambling a retransmitted data packet before retransmission using a pseudo-randomly varying scrambling technique.

53. The transmitter arrangement (20) according to claim 50, further comprising a modulator (32).

54. A receiver arrangement (40) for receiving at least one data stream transmitted by the transmitter arrangement (20) according to claim 50.

55. The receiver arrangement (40) according to claim 54, further comprising audio processing electronics (49).

56. The receiver arrangement (40) according to claim 54, further comprising a descrambler (43) for descrambling a retransmitted data packet upon reception.

57. The receiver arrangement (40) according to claim 56, further comprising a pre-detection accumulator for integrating multiple retransmitted data packets.