U.S. patent application number 13/588875 was filed with the patent office on 2012-12-06 for error correction scheme in a hearing system wireless network.
This patent application is currently assigned to GN ReSound A/S. Invention is credited to Brian Dam PEDERSEN.
Application Number | 20120311409 13/588875 |
Document ID | / |
Family ID | 40527882 |
Filed Date | 2012-12-06 |
United States Patent
Application |
20120311409 |
Kind Code |
A1 |
PEDERSEN; Brian Dam |
December 6, 2012 |
ERROR CORRECTION SCHEME IN A HEARING SYSTEM WIRELESS NETWORK
Abstract
A method of wireless data communication between a hearing
instrument and another device, includes receiving N data packages
A.sub.1, A.sub.2, . . . , A.sub.N, wherein the N data packages are
obtained by dividing a data package D, receiving data package C,
wherein the data package C is formed as a function of A.sub.1,
A.sub.2, . . . , A.sub.N in accordance with a relationship
C=(A.sub.1, A.sub.2, . . . , A.sub.N), performing error detection,
and recovering A.sub.E, one of the data packages A.sub.1, A.sub.2,
. . . , A.sub.N that contains an error, in accordance with a
relationship A.sub.E=(A.sub.1, A.sub.2, . . . , C, . . . ,
A.sub.N), in which A.sub.1, A.sub.2, . . . , C, . . . , A.sub.N
indicates that the data package C is used in place of A.sub.E in a
list of arguments for the function .
Inventors: |
PEDERSEN; Brian Dam;
(Ringsted, DK) |
Assignee: |
GN ReSound A/S
Ballerup
DK
|
Family ID: |
40527882 |
Appl. No.: |
13/588875 |
Filed: |
August 17, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12353192 |
Jan 13, 2009 |
8265099 |
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13588875 |
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Current U.S.
Class: |
714/776 ;
714/E11.032 |
Current CPC
Class: |
H04R 25/558 20130101;
H04R 25/554 20130101; H04L 1/004 20130101; H04R 2225/55 20130101;
H04R 25/70 20130101; H04L 1/008 20130101; H04R 25/552 20130101 |
Class at
Publication: |
714/776 ;
714/E11.032 |
International
Class: |
H03M 13/05 20060101
H03M013/05; G06F 11/10 20060101 G06F011/10; H04B 7/26 20060101
H04B007/26 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 22, 2008 |
DK |
PA 2008 01830 |
Claims
1-22. (canceled)
23. A method of data communication between a hearing instrument and
another device, comprising: forming a data correction package C as
a function of at least some of a plurality of data packages
A.sub.1, A.sub.2, . . . , A.sub.N; and transmitting the data
correction package C; wherein the act of transmitting the data
correction package C is performed by the other device regardless of
whether the hearing instrument detects an error; and wherein the
data correction package C is for recovering A.sub.E, one of the
data packages A.sub.1, A.sub.2, . . . , A.sub.N that contains the
error.
24. The method of claim 23, wherein the data correction package C
is formed in accordance with a relationship C=(A.sub.1, A.sub.2, .
. . , A.sub.N); and wherein the data package C is formed to recover
A.sub.E in accordance with a relationship A.sub.E=(A.sub.1,
A.sub.2, . . . , C, . . . , A.sub.N), in which A.sub.1, A.sub.2, .
. . , C, . . . , A.sub.N indicates that the data correction package
C is used in place of A.sub.E in a list of arguments for the
function .
25. The method of claim 24, wherein the function and the function
are identical.
26. The method of claim 25, wherein the function is an exclusive-or
function so that C=A.sub.1 .sym. A.sub.2 .sym. . . . .sym. A.sub.N
and A.sub.E=A.sub.1 .sym. A.sub.2 .sym. . . . .sym. C .sym. . . .
.sym. A.sub.N.
27. The method of claim 26, wherein N is equal to 2 so that
C=A.sub.1 .sym. A.sub.2 and A.sub.1=C .sym. A.sub.2 and
A.sub.2=A.sub.1 .sym. C.
28. The method of claim 23, further comprising transmitting the
data packages A.sub.1, A.sub.2, . . . , A.sub.N from the other
device to the hearing instrument.
29. The method of claim 28, wherein at least some of the packages
A.sub.i, C are wirelessly transmitted in respective different
frequency channels.
30. The method of claim 23, wherein the error is due to noise in a
communication channel.
31. The method of claim 23, wherein the data correction package C
is received by the hearing instrument in response to a detection of
the error by the hearing instrument.
32. A method of data communication between a hearing instrument and
another device, comprising: receiving N data packages A.sub.1,
A.sub.2, . . . , A.sub.N; performing error detection; receiving
data correction package C, wherein the data correction package C is
formed as a function of at least some of the N data packages
A.sub.1, A.sub.2, . . . , A.sub.N; and recovering A.sub.E, one of
the data packages A.sub.1, A.sub.2, . . . , A.sub.N that contains
an error based on the data correction package C; wherein the act of
receiving the data correction package C is performed in response to
a detection of the error; wherein both the act of receiving the
data correction package C and the act of performing the error
detection are performed by the hearing instrument; and wherein the
data correction package C is received from the other device.
33. The method of claim 32, wherein the data correction package C
is formed in accordance with a relationship C=(A.sub.1, A.sub.2, .
. . , A.sub.N); and wherein A.sub.E is recovered in accordance with
a relationship A.sub.E=(A.sub.1, A.sub.2, . . . , C, . . . ,
A.sub.N), in which A.sub.1, A.sub.2, . . . , C, . . . , A.sub.N
indicates that the data package C is used in place of A.sub.E in a
list of arguments for the function .
34. The method of claim 33, wherein the function and the function
are identical.
35. The method of claim 34, wherein the function is an exclusive-or
function so that C=A.sub.1 .sym. A.sub.2 .sym. . . . .sym. A.sub.N
and A.sub.E=A.sub.1 .sym. A.sub.2 .sym. . . . .sym.C .sym. . . .
.sym. A.sub.N.
36. The method of claim 35, wherein N is equal to 2 so that
C=A.sub.1 .sym. A.sub.2 and A.sub.1=C .sym. A.sub.2 and
A.sub.2=A.sub.1 .sym. C.
37. The method of claim 32, wherein at least some of the packages
A.sub.i, C are received wirelessly in respective different
frequency channels.
38. The method of claim 32, wherein the error is due to noise in a
communication channel.
39. The method of claim 32, wherein the error detection is
performed on each of the N data packages.
40. The method of claim 32, wherein the act of receiving the data
correction package C in response to the detection of the error
provides power saving for the hearing instrument that receives the
data correction package C.
41. The method of claim 32, wherein the other device is carried by
a user of the hearing instrument, and the hearing instrument and
the other device are configured to communicate with each other
through a Bluetooth network.
42. A device, comprising: a processing unit configured to form a
data correction package as a function of a plurality of data
packages; and a communication device configured to transmit the
data correction package for reception by a hearing instrument
regardless of whether the hearing instrument detects an error;
wherein the data correction package is for recovering one of the
data packages that contains the error.
43. The device of claim 42, wherein the communication device
comprises a Bluetooth device.
44. The device of claim 42, wherein the error is due to noise in a
communication channel.
45. The device of claim 42, wherein the communication device is
also configured to transmit the plurality of data packages for
reception by the hearing instrument.
46. The device of claim 45, wherein at least some of the plurality
of packages and the data correction package are wirelessly
transmitted in different respective frequency channels.
47. The device of claim 42, wherein the processing unit and the
communication device are parts of another hearing instrument that
is in communication with the hearing instrument.
48. A hearing system comprising the device of claim 47, and the
hearing instrument.
49. The hearing system of claim 48, wherein the hearing instrument
is configured to receive the data correction package in response to
a detection of the error by the hearing instrument.
50. The hearing system of claim 48, wherein the hearing instrument
comprises a first hearing aid, and the other hearing instrument
comprises a second hearing aid.
51. The hearing system of claim 48, wherein the hearing instrument
comprises a controller configured to control a receiver in the
hearing instrument to receive the data correction package to
provide power saving for the hearing instrument.
52. A hearing instrument, comprising: a receiver for receiving a
plurality of data packages; and a controller that controls the
receiver to receive a data correction package transmitted by a
device, wherein the controller is configured to control the
receiver to receive the data correction package in response to a
detection of an error by the hearing instrument, the controller
being a part of the hearing instrument; wherein the data correction
package is based at least on some of the data packages, and is for
recovering one of the data packages that contains the error.
53. A hearing system comprising the hearing instrument of claim 52,
and the device, wherein the device comprises an additional hearing
instrument.
54. The hearing system of claim 53, wherein the device is
configured to transmit the data correction package regardless of
whether the hearing instrument detects the error.
55. The hearing system of claim 53, wherein the hearing instrument
comprises a first hearing aid, and the additional hearing
instrument comprises a second hearing aid.
56. The hearing instrument of claim 52, wherein the receiver is
configured to receive the data correction package through a
Bluetooth network.
57. The hearing instrument of claim 52, wherein the receiver is
configured to receive the plurality of data packages and the data
correction package in respective different frequency channels.
58. The hearing instrument of claim 52, wherein the error is due to
noise in a communication channel.
59. The hearing instrument of claim 52, wherein the controller is
configured to control the receiver to receive the data correction
package to provide power saving for the hearing instrument.
Description
RELATED APPLICATION DATA
[0001] This application claims priority to and the benefit of
Danish Patent Application No. PA 2008 01830, filed Dec. 22, 2008,
the entire disclosure of which is expressly incorporated by
reference.
FIELD
[0002] The present application relates to a hearing instrument
wireless network for wireless interconnection of hearing
instruments with each other, and wireless interconnection of
hearing instruments with other devices, such as remote controllers,
fitting instruments, mobile phones, media players, headsets, door
bells, alarm systems, broadcast systems, such as tele coil
replacement, etc, etc.
BACKGROUND
[0003] WO 2004/110099 discloses a hearing aid wireless network with
a communication protocol that is simple thereby requiring a small
amount of code and power consumption during operation. Further, the
acquisition time is low, and the latency is low.
[0004] Numerous schemes of correcting data transmission errors in
noisy communication channels are known in the art. Typically, a
number of bits is added to data bits in a data package according to
a certain encoding scheme making it possible to detect a certain
number of bit errors caused by noise in the communication channel
and also correct a certain, typically smaller, number of bit errors
in a de-coder. Some schemes include re-transmission of data
packages. Error correction schemes increase the time needed for
transmission and reception of a certain number of data bits, and
wireless communication circuitry requires significant amounts of
power during reception and transmission of data.
[0005] Typically, in a hearing instrument, such as a hearing aid,
only a limited amount of power is available from the power supply.
For example, in a hearing aid, power is typically supplied from a
conventional ZnO.sub.2 battery.
SUMMARY
[0006] Thus, in a hearing system, it is desirable to minimize the
time transmitters and receivers are actively performing
transmission and reception, respectively. For example, it is
desirable to minimize re-transmission of data packets.
[0007] Accordingly, a hearing system is provided, comprising a
hearing instrument having a receiver for wireless data
communication between the hearing instrument and another device in
a wireless network. The hearing instrument may further have a
communication controller that is configured for controlling the
wireless data communication.
[0008] In accordance with the present error correction scheme, a
data package D containing B bits to be transmitted, is divided into
a number N of data packages A.sub.1, A.sub.2, . . . , A.sub.N,
Preferably, but not necessarily, data packages A.sub.1, A.sub.2, .
. . , A.sub.N contain identical number of bits
B N . ##EQU00001##
In order to be able to detect and correct possible bit errors in
one data package A.sub.I a further data package C is formed as a
function of A.sub.1, A.sub.2, . . . , A.sub.N:
C=(A.sub.1, A.sub.2, . . . , A.sub.N).
[0009] Then, the data packages A.sub.1, A.sub.2, . . . , A.sub.N,
and C are transmitted wirelessly from a transmitting device in the
wireless network.
[0010] In the hearing instrument or another device connected to the
wireless network and for which the transmitted data packages are
intended, the data receiver is activated, e.g. turned on, to
perform data reception of data packages A.sub.1, A.sub.2, . . . ,
A.sub.N, and C. The data receiver also performs error detection
and, in case of detection of error(s) in one of the data packages
A.sub.1, A.sub.2, . . . , A.sub.N, namely A.sub.E, data recovery is
performed based on the remaining data packages A.sub.1, A.sub.2, .
. . , A.sub.N, and C in accordance with:
A.sub.E=(A.sub.1, A.sub.2, . . . , C, . . . , A.sub.N),
wherein A.sub.1, A.sub.2, . . . , C, . . . , A.sub.N indicates that
data package C replaces the defective data package A.sub.E in the
list of arguments of function . A.sub.E may be any one of the data
packages A.sub.1, A.sub.2, . . . , A.sub.N.
[0011] Thus, the function is used to calculate redundant data
information inserted into the transmitted data stream in accordance
with specific algebraic relations so that the received data stream,
in the event that errors have been introduced during data
transmission, can be corrected using the corresponding reversed
specific algebraic relations constituting the function .
[0012] It should be noted that division of original data package D
with B bits into a number of data packages A.sub.1, A.sub.2, . . .
, A.sub.N, e.g. of the same size
B N , ##EQU00002##
leads to the advantage that only one extra package C with a small
number of bits, e.g.
B N , ##EQU00003##
needs to be transmitted and received. Thus, the time the receiver
needs to be activated in order to be able to perform data recovery
is only increased by
B N . ##EQU00004##
[0013] Preferably, the communication controller is configured to
control the receiver in such a way that reception of data package C
takes place solely in case of detection of error(s) in data
packages A.sub.1, A.sub.2, . . . , A.sub.N. Hereby further power
consumption by the receiver is saved when no error(s) is detected,
since reception of data package C is not performed in case of error
free data transmission of A.sub.1, A.sub.2, . . . , A.sub.N.
[0014] An error in the received data stream may be detected using
e.g. parity bits, Hamming code, checksum, cyclic redundancy check,
etc.
[0015] Accordingly, a hearing system is provided comprising a
hearing instrument having a receiver for wireless data
communication between the hearing instrument and another device in
a wireless network, and a communication controller that is
configured for controlling the receiver for data reception of data
packages A.sub.1, A.sub.2, . . . , A.sub.N, and C. The receiver is
further configured for performing error detection, and in case of
detection of an error in one of the data packages A.sub.1, A.sub.2,
. . . , C, . . . , A.sub.N, namely A.sub.E, for recovering the data
package A.sub.E in accordance with: A.sub.E=(A.sub.1, A.sub.2, . .
. C, . . . , A.sub.N), wherein A.sub.1, A.sub.2, . . . , C, . . . ,
A.sub.N indicates that data package C replaces defective data
package A.sub.E in the list of arguments of function .
[0016] Thus, in a device connected in the wireless network, a
communication controller of the device may be configured for always
performing data reception of data package C in addition to data
reception of data packages A.sub.1, A.sub.2, . . . , A.sub.N
whether an error has been detected or not, for example in a device
with plenty of power available. Still, data recovery may be
performed solely in response to detection of an error in one,
namely A.sub.E, of the received data packages A.sub.1, A.sub.2, . .
. , A.sub.N.
[0017] However, in a device with limited amount of power available,
data reception of data package C may be performed solely in
response to detection of an error in one of the received data
packages A.sub.1, A.sub.2, . . . , A.sub.N.
[0018] According to the present error correction scheme, the
transmitting device always transmits the extra data package C for
possible subsequent error correction; however, typically the
transmitting device is a device with a large power supply, such as
a remote controller, a fitting instrument, a mobile phone, a media
players a headset, a door bell, an alarm system, a broadcast
system, etc. The transmitting device may also be a hearing
instrument.
[0019] Function and function may be identical functions.
[0020] In one embodiment, is an exclusive-or function so that
C=A.sub.1 .sym. A.sub.2 .sym. . . . .sym. A.sub.N
and
A.sub.E=A .sub.1.sym. A.sub.2 .sym. . . . .sym. C.sym. . . . .sym.
A.sub.N.
[0021] For example, N may be equal to 2 so that data package D
containing B bits to be transmitted is divided into 2 data packages
A.sub.1 and A.sub.2, each of which contains
B 2 ##EQU00005##
bits. In order to be able to detect and correct possible bit errors
in a data package, a further data package C is formed as a function
of A.sub.1 and A.sub.2:
C=A.sub.1 .sym. A.sub.2.
[0022] Then, the data packages A.sub.1 and A.sub.2, and C are
transmitted wirelessly from a transmitting device in the wireless
network.
[0023] In the hearing instrument or another device connected to the
wireless network and for which the transmitted data packages are
intended, the data receiver is activated, e.g. turned on, to
perform data reception of data packages A.sub.1 and A.sub.2 and C.
The data receiver also performs error detection and, in case of
detection of error(s) in A.sub.1 or A.sub.2, data recovery is
performed based on:
A.sub.1=C .sym. A.sub.2 or A.sub.2=C .sym. A.sub.1.
[0024] It should be noted that division of original data package D
with B bits into two data packages A.sub.1 and A.sub.2 of the same
size
B 2 ##EQU00006##
bits, leads to the advantage that only one extra package C with
B 2 ##EQU00007##
bits needs to be transmitted and received. Thus, the time the
receiver needs to be activated in order to be able to perform data
recovery is only increased by
B 2 . ##EQU00008##
[0025] Preferably, the communication controller is configured to
control the receiver in such a way that reception of data package C
takes place solely in case of detection of error(s) in data package
A.sub.1 or A.sub.2. Hereby further power consumption by the
receiver is saved when no error(s) is detected, since reception of
data package C is not performed in case of error free data
transmission of A.sub.1 and A.sub.2.
[0026] The limited power supply requirement of the provided error
correction scheme makes it suitable for incorporation in a hearing
instrument with limited power supply capabilities.
[0027] The hearing instrument may be a hearing aid, a tinnitus
relieving device, a tinnitus therapy device, a noise suppression
device, etc., or any combination of two or more of such
devices.
[0028] The receiver and transmitter of the hearing instrument may
be comprised in a radio chip, such as the Nordic Semiconductor
radio chip "nRF24I01". A radio chip of this type draws significant
amounts of current both when it transmits and receives. A
conventional ZnO.sub.2 battery is only capable of supplying the
required amount of current for a limited time period, typically 1
millisecond. Continued supply of the required amount of current
leads to a lowered supply voltage below which digital signal
processing circuitry will stop operating properly. Further, the
ZnO.sub.2 battery will require time to recover after having
supplied current to the radio chip during communication. Typically,
the radio chip duty cycle, i.e. the percentage of radio turn-on
time with respect to the sum of the radio turn-on and radio
turn-off time, must be kept below 10%.
[0029] In one embodiment, the receiver and communication controller
operate according to a frequency diversification or spread spectrum
scheme, i.e. the frequency range utilized by the wireless network
is divided into a number of frequency channels, and data
communication switch channels according to a predetermined scheme
so that transmissions are distributed over the frequency range.
[0030] Preferably, a frequency hopping algorithm is provided that
allows devices in the network to calculate what frequency channel
the network will use at any given point in time without relying on
the history of the network. For example, based on the present
frequency channel number, a pseudo-random number generator
calculates the next frequency channel number. This facilitates
synchronization of a new device in the network, e.g. the new device
comprises the same pseudo-random number generator as the devices
already connected in the network. Thus, upon receipt of the current
frequency channel number during acquisition, the new device will
calculate the same next frequency channel number as the other
devices in the network.
[0031] In a network operating according to a spread spectrum
scheme, the communication has a low sensitivity to noise, since
noise is typically present in specific frequency channels, and
communication will only be performed in a specific frequency
channel for a short time period after which communication is
switched to another frequency channel.
[0032] Advantageously, each of the data packages A.sub.1, A.sub.2,
. . . , A.sub.N may be transmitted in an individual frequency
channel, i.e. subsequent to the transmission of one data package
A.sub.P, a frequency hop is performed before transmission of the
next data package A.sub.P+1 of the data packages A.sub.1, A.sub.2,
. . . , A.sub.N. As mentioned above, noise is typically present in
specific frequency channels so that a typical transmission error of
this transmission scheme generates data corruption of a single
package of the data packages A.sub.1, A.sub.2, . . . , A.sub.N
while no errors are generated in the remaining data packages.
[0033] It is a further advantage of the hearing system operating
according to a spread spectrum scheme that several networks may
co-exist in close proximity, for example two or more hearing
instrument users may be present in the same room without network
interference, since the probability of two networks simultaneously
using a specific frequency channel will be very low. Likewise, the
hearing instrument network may coexist with other wireless networks
utilizing the same frequency band, such as Bluetooth networks or
other wireless local area networks. Hearing instruments according
to some embodiments described herein may advantageously be
incorporated into a binaural hearing aid system, wherein two
hearing aids are interconnected through the wireless network for
digital exchange of data, such as audio signals, signal processing
parameters, control data, such as identification of signal
processing programs, etc, etc, and optionally interconnected with
other devices, such as a remote control, etc.
[0034] The receivers and transmitters of devices in the network may
operate in accordance with a time-division-multiple-access (TDMA)
frame structure, wherein time is divided into frames comprising a
set of numbered time slots. Different devices in the network
communicate in specific respective time slots. Thus, when connected
in the network, the frames of the devices are synchronised.
[0035] Every device in the network has its own identification
number, e.g. a 32-bit number. Globally unique identities are not
required since the probability of two users having hearing
instruments with identical identifications is negligible.
[0036] The hearing system may operate in the 2.4 GHz industrial
scientific medical (ISM) band. The ISM band may for example be
divided into 80 frequency channels of 1 MHz bandwidth. A frequency
hopping TDM (Time Division Multiplex) scheme is preferred. During
acquisition, the frequency hopping scheme may comprise a reduced
number of frequency channels, e.g. less than 16 channels,
preferably 4-8 channels, for faster acquisition. Channels of the
reduced set of frequency channels are denoted acquisition channels.
Preferably, the acquisition channels are distributed uniformly
throughout the frequency band utilised by the network.
[0037] The duration of a time slot may for example be 1250 .mu.s
(twice the length of a minimum Bluetooth.TM. slot). The slots may
be numbered from 0 to 255.
[0038] 256 slots, i.e. slot 0 to slot 255, constitute a frame.
Frames are also numbered.
[0039] Among factors influencing selection of the length of a slot,
is the required lower latency of the system and a desired low
overhead with respects to headers and PLL (Phase Locked Loop)
locking. Preferably, the slot length is a multiple of 625 .mu.s,
facilitating (i.e. not prevent) that the protocol can be
implemented on BLUETOOTH.TM. enabled devices.
[0040] Each slot (except slot 128) is used for transmission by one
specific device so that data collisions inside the network are
prevented. Any slave device may transmit data in slot 128 and hence
collisions may occur in this slot. The master device transmits
timing information in slot 0. The slot and frame counters of a
slave device are synchronized with the respective counters of the
master device of the network.
[0041] A device may use one or more slots for transmission of data.
Slots may be allocated during manufacture of a given device, or,
slots may be allocated dynamically during acquisition. Preferably,
the allocation table is stored in the master device.
[0042] In order to lower power consumption in the hearing
instrument, the hearing instrument receiver and transmitter are
activated, i.e. allowed to operate for reception and transmission,
respectively, e.g. turned on, only in their respective time slots.
Further, the bit rate can be made scalable in such a system: When
low bit transfer rates are required, the transceiver need only be
active a small fraction of the time. In this way power can be
saved.
[0043] In accordance with some embodiments, a method of wireless
data communication between a hearing instrument and another device,
includes dividing a data package D into N data packages A.sub.1,
A.sub.2, . . . , A.sub.N, forming a data package C as a function of
A.sub.1, A.sub.2, . . . , A.sub.N in accordance with a relationship
C=(A.sub.1, A.sub.2, . . . , A.sub.N), wirelessly transmitting the
data packages A.sub.1, A.sub.2, . . . , A.sub.N, and wirelessly
transmitting the data package C, wherein the data package C is for
recovering A.sub.E, one of the data packages A.sub.1, A.sub.2, . .
. , A.sub.N that contains an error, in accordance with a
relationship A.sub.E=(A.sub.1, A.sub.2, . . . , C, . . . ,
A.sub.N), in which A.sub.1, A.sub.2, . . . , C, . . . , A.sub.N
indicates that the data package C is used in place of A.sub.E in a
list of arguments for the function .
[0044] In accordance with other embodiments, a system for wireless
data communication between a hearing instrument and another device
includes means for dividing a data package D into N data packages
A.sub.1, A.sub.2, . . . , A.sub.N, means for forming a data package
C as a function of A.sub.1, A.sub.2, . . . , A.sub.N in accordance
with a relationship C=(A.sub.1, A.sub.2, . . . , A.sub.N), and
means for wirelessly transmitting the data packages A.sub.1,
A.sub.2, . . . , A.sub.N, and for wirelessly transmitting the data
package C, wherein the data package C is for recovering A.sub.E,
one of the data packages A.sub.1, A.sub.2, . . . , A.sub.N that
contains an error, in accordance with a relationship
A.sub.E=(A.sub.1, A.sub.2, . . . , C, . . . , A.sub.N), in which
A.sub.1, A.sub.2, . . . , C, . . . , A.sub.N indicates that the
data package C is used in place of A.sub.E in a list of arguments
for the function .
[0045] In accordance with other embodiments, a method of wireless
data communication between a hearing instrument and another device,
includes receiving N data packages A.sub.1, A.sub.2, . . . ,
A.sub.N, wherein the N data packages are obtained by dividing a
data package D, receiving data package C, wherein the data package
C is formed as a function of A.sub.1, A.sub.2, . . . , A.sub.N in
accordance with a relationship C=(A.sub.1, A.sub.2, . . . ,
A.sub.N), performing error detection, and recovering A.sub.E, one
of the data packages A.sub.1, A.sub.2, . . . , A.sub.N that
contains an error, in accordance with a relationship
A.sub.E=(A.sub.1, A.sub.2, . . . , C, . . . , A.sub.N), in which
A.sub.1, A.sub.2, . . . , C, . . . , A.sub.N indicates that the
data package C is used in place of A.sub.E in a list of arguments
for the function .
[0046] In accordance with other embodiments, a system for wireless
data communication between a hearing instrument and another device
includes means for receiving N data packages A.sub.1, A.sub.2, . .
. , A.sub.N, and data package C, wherein the N data packages are
obtained by dividing a data package D, and wherein the data package
C is formed as a function of A.sub.1, A.sub.2, . . . , A.sub.N in
accordance with a relationship C=(A.sub.1, A.sub.2, . . . ,
A.sub.N), means for performing error detection, and means for
recovering A.sub.E, one of the data packages A.sub.1, A.sub.2, . .
. , A.sub.N that contains an error, in accordance with a
relationship A.sub.E=(A.sub.1, A.sub.2, . . . , C, . . . ,
A.sub.N), in which A.sub.1, A.sub.2, . . . , C, . . . , A.sub.N
indicates that the data package C is used in place of A.sub.E in a
list of arguments for the function .
[0047] In accordance with other embodiments, a hearing system
includes a hearing instrument having a receiver for wireless data
communication with another device in a wireless network, and a
communication controller that is configured for controlling the
wireless data communication, wherein the other device is configured
for transmission of data packages A.sub.1, A.sub.2, . . . ,
A.sub.N, C, the data package C being a function of A.sub.1,
A.sub.2, . . . , A.sub.N in accordance with a relationship
C=(A.sub.1, A.sub.2, . . . , A.sub.N), and wherein the
communication controller is configured for controlling the receiver
for receiving the data packages A.sub.1, A.sub.2, . . . , A.sub.N,
and C, performing error detection, and recovering A.sub.E, one of
the data packages A.sub.1, A.sub.2, . . . , A.sub.N that contains
an error, in accordance with a relationship A.sub.E=(A.sub.1,
A.sub.2, . . . , C, . . . , A.sub.N), in which A.sub.1, A.sub.2, .
. . , C, . . . , A.sub.N indicates that the data package C is used
in place of A.sub.E in a list of arguments for the function
DESCRIPTION OF THE DRAWING FIGURES
[0048] The above and other features and advantages will become more
apparent to those of ordinary skill in the art by describing in
detail exemplary embodiments thereof with reference to the attached
drawings in which:
[0049] FIG. 1 schematically illustrates a hearing system wireless
network, and
[0050] FIG. 2 is a blocked schematic of a transceiver and
communication controller according to some embodiments.
DETAIL DESCRIPTION
[0051] Some of the embodiments will now be described more fully
hereinafter with reference to the accompanying drawings. The
claimed invention may, however, be embodied in different forms and
should not be construed as limited to the embodiments set forth
herein. Thus, the illustrated embodiments are not intended as an
exhaustive description of the invention or as a limitation on the
scope of the invention. In addition, an illustrated embodiment
needs not have all the aspects or advantages shown. An aspect or an
advantage described in conjunction with a particular embodiment is
not necessarily limited to that embodiment and can be practiced in
any other embodiments even if not so illustrated. Like reference
numerals refer to like elements throughout.
[0052] FIG. 1 schematically illustrates a hearing system comprising
a binaural hearing aid with a left ear hearing aid and a right ear
hearing aid, each of which has a transceiver and communication
controller for connection with a wireless network interconnecting
the two hearing aids, and interconnecting the hearing aids and a
plurality of other devices in the wireless network. In the example
illustrated in FIG. 1, a doorbell, a mobile phone, a cordless
phone, a TV-set, and a fitting instrument are also connected to the
wireless network.
[0053] The illustrated embodiment operates in the 2.4 GHz
industrial scientific medical (ISM) band. It comprises 80 frequency
channels of 1 MHz bandwidth. The receivers and communication
controllers of the shown devices operate according to a frequency
diversification or spread spectrum scheme, i.e. the frequency range
utilized by the network is divided into the 80 frequency channels,
and transmissions switch channels according to a predetermined
scheme so that transmissions are distributed over the ISM frequency
range. A frequency hopping algorithm is provided that allows
devices in the network to calculate what frequency channel the
network will use at any given point in time without relying on the
history of the network, e.g. based on the present frequency channel
number, a pseudo-random number generator calculates the next
frequency channel number. This facilitates synchronization of a new
device in the network, e.g. the new device comprises the same
pseudo-random number generator as the devices already connected in
the network. Thus, upon receipt of the current frequency channel
number during acquisition, the new device will calculate the same
next frequency channel number as the other devices in the network.
Preferably, one device in the network operates a master device of
the network. Other devices in the system synchronize to the timing
of the master device, and preferably, the master device is a
hearing instrument, since the hearing instrument user will always
carry the hearing instrument when he or she uses the network.
[0054] Communication in the illustrated network has low sensitivity
to noise, since noise is typically present in specific frequency
channels, and communication will only be performed in a specific
frequency channel for a short time period after which communication
is switched to another frequency channel.
[0055] A frequency hopping TDM scheme is utilized. During
acquisition, the frequency hopping scheme comprises a reduced
number of frequency channels, e.g. less than 16 channels,
preferably 8 channels, for faster acquisition. Members of the
reduced set of frequency channels are denoted acquisition channels.
Preferably, the acquisition channels are distributed uniformly
throughout the frequency band utilised by the network.
[0056] According to the time-division-multiple-access (TDMA) frame
structure, the devices in the network transmit and receive data
according to a coordinated time schedule wherein the time is
divided into numbered time slots and different devices in the
network communicate, e.g. receive data, in specific respective time
slots. In order to lower power consumption in the hearing aid, the
hearing aid receiver is turned on only in its time slot. Further,
the bit rate can be made scalable in such a system: When low bit
transfer rates are required, the receiver need only be active a
small fraction of the time. In this way further power can be saved.
A device may use one or more slots for transmission of data. Slots
may be allocated during manufacture of a given device, or, slots
may be allocated dynamically during acquisition. Preferably, the
allocation table is stored in the master device.
[0057] In the illustrated hearing system, a data package D
containing 32 bits to be transmitted is divided into 2 data
packages A.sub.1 and A.sub.2, each of which contains 16 bits. In
order to be able to detect and correct possible bit errors in a
data package, a further data package C is formed as a function of
A.sub.1 and A.sub.2:
C=A.sub.1 .sym. A.sub.2.
For example: [0058] D=11100110000110100101001110110001 and thus:
[0059] A.sub.1=1110011000011010 [0060] A.sub.2=0101001110110001
whereby [0061] C=1011010110101011. Data recovery is now possible,
since A.sub.1=C .sym. A.sub.2 and A.sub.2=C .sym. A.sub.1: [0062]
A.sub.2=0101001110110001 [0063] C=1011010110101011 [0064]
A.sub.1=1110011000011010 and [0065] A.sub.1=1110011000011010 [0066]
C=1011010110101011. [0067] A.sub.2=0101001110110001
[0068] In the hearing instrument or another device connected to the
wireless network and for which the transmitted data packages are
intended, the data receiver is activated, e.g. turned on, to
perform data reception of transmitted data packages A.sub.1 and
A.sub.2 and C: [0069]
111001100001101001010011101100011011010110101011.
[0070] The data receiver also performs error detection and in case
of detection of error(s) in A.sub.1 or A.sub.2, data recovery is
performed based on:
A.sub.1=C .sym. A.sub.2 or A.sub.2=C .sym. A.sub.1.
[0071] Thus, if A.sub.1 is corrupted, A.sub.1 is recovered by
performing the exclusive-or operation on C and A.sub.2.
Correspondingly, if A.sub.2 is corrupted, A.sub.2 is recovered by
performing the exclusive-or operation on C and A.sub.1.
[0072] It should be noted that division of original data package D
with 32 bits into two data packages A.sub.1 and A.sub.2 of 16 bits,
leads to the advantage that only one extra package C with 16 bits
needs to be transmitted and received. Thus, the time the receiver
needs to be activated in order to be able to perform data recovery
is only increased by 16 bits transmission time. Division of
original data package D into more than two data packages A further
reduces the extra time the receiver needs to be activated in order
to be able to perform data recovery.
[0073] Preferably, the communication controller is configured to
control the receiver in such a way that reception of data package C
takes place solely in case of detection of error(s) in data package
A.sub.1 or A.sub.2. Hereby further power consumption by the
receiver is saved, since the receiver is only active during
reception of data packages A.sub.1 and A.sub.2 unless an error is
detected during transmission of A.sub.1 and A.sub.2.
[0074] FIG. 2 is a blocked schematic of a transceiver and
communication controller according to some embodiments. FIG. 2 also
illustrates the major data flow into and out of the units. The RF
chip interface receives a data stream from the RF chip.
[0075] The correlator 2 extracts the slot and frame timing from the
sync word, so that the rest of the receive chain can be
synchronized. Based on this timing, the header extraction block 3
analyses the package header and extracts the slot number and
package length. Any errors in the header are reported. The data
de-whitening block 4 de-whitens the package data. The data is then
converted to 16 bits parallel by the serial-parallel conversion
block 5. The package data is stored in an internal data buffer 6 by
the data buffer interface 7. The data is then accessible to the DSP
via the DSP interface 8 through the peripheral bus. A CRC (Cyclic
Redundancy Check) check can also be performed on the package data
9. All internal configuration registers and results of header
checks, CRC errors etc are accessible though the DSP interface.
Slot and frame counters 10 are also provided as well as a number of
hardware timers 11.
[0076] The controller state machine 12 is responsible for overall
timing of the base-band engine.
[0077] At transmission, the RF chip interface 1 sends SPI commands
to the RF chip for configuration.
[0078] The DSP writes a package of data to the data buffer 6, 7 via
the DSP interface 8. The package data has a CRC calculated via the
data CRC generation block 9. The combined data payload and CRC are
then converted to serial 5 and whitened 4. The package header is
constructed by the header generation block 3 and then appended to
the data. The completed package is then streamed to the RF chip by
the RF chip interface 1.
[0079] Although particular embodiments have been shown and
described, it will be understood that they are not intended to
limit the present inventions, and it will be obvious to those
skilled in the art that various changes and modifications may be
made without departing from the spirit and scope of the present
inventions. The specification and drawings are, accordingly, to be
regarded in an illustrative rather than restrictive sense. The
claimed inventions are intended to cover alternatives,
modifications, and equivalents.
* * * * *