U.S. patent number RE46,704 [Application Number 13/865,398] was granted by the patent office on 2018-02-06 for method for establishing packet-switched connection, and cellular network utilizing the method, and cellular terminal.
This patent grant is currently assigned to Nokia Technologies Oy. The grantee listed for this patent is Nokia Corporation. Invention is credited to Pekka Kuure, Hannu Toyryla, Jari Vallstrom, Markku Vimpari, Timo Vittaniemi.
United States Patent |
RE46,704 |
Kuure , et al. |
February 6, 2018 |
Method for establishing packet-switched connection, and cellular
network utilizing the method, and cellular terminal
Abstract
The invention relates to method applicable in a packet-switched
cellular network for voice connections, by which method a new
dedicated channel can be established quickly using the existing
dedicated channel of the voice connection. The establishment of the
new dedicated channel utilizes the previous dedicated channel the
existence of which is extended by sending to at least the receiving
terminals post-speech packets according to the invention. The
post-speech packets produce a 2-second delay, approximately, which
is sufficient to establish a new dedicated channel between
terminals participating in a session.
Inventors: |
Kuure; Pekka (Espoo,
FI), Vimpari; Markku (Oulu, FI), Vallstrom;
Jari (Oulu, FI), Vittaniemi; Timo (Oulu,
FI), Toyryla; Hannu (Helsinki, FI) |
Applicant: |
Name |
City |
State |
Country |
Type |
Nokia Corporation |
Espoo |
N/A |
FI |
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Assignee: |
Nokia Technologies Oy (Espoo,
FI)
|
Family
ID: |
1000002832375 |
Appl.
No.: |
13/865,398 |
Filed: |
April 18, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
10727726 |
Dec 4, 2003 |
8203974 |
Jun 19, 2012 |
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Foreign Application Priority Data
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Dec 13, 2002 [FI] |
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20022195 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W
76/25 (20180201); H04W 76/25 (20180201); H04M
3/56 (20130101); H04W 4/10 (20130101); H04L
12/1827 (20130101); H04W 76/45 (20180201); H04W
72/005 (20130101); H04W 72/005 (20130101); H04W
4/10 (20130101); H04L 65/4038 (20130101); H04W
76/45 (20180201) |
Current International
Class: |
H04L
12/16 (20060101); H04H 20/71 (20080101); H04M
3/56 (20060101); H04W 4/10 (20090101); H04W
72/00 (20090101); H04W 76/00 (20090101); H04L
29/06 (20060101); H04L 12/18 (20060101) |
Field of
Search: |
;370/260,312 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0 830 040 |
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Mar 1998 |
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EP |
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0 830 040 |
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Mar 1998 |
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EP |
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1 006 695 |
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Jun 2000 |
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EP |
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1 139 613 |
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Oct 2001 |
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EP |
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1 257 096 |
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Nov 2002 |
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EP |
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WO-0079808 |
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Dec 2000 |
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WO |
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WO-02/09463 |
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Jan 2002 |
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WO |
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WO 02085051 |
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Oct 2002 |
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WO |
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Primary Examiner: Heneghan; Matthew
Attorney, Agent or Firm: Harrington & Smith
Claims
The invention claimed is:
1. A method, comprising: communicating in a cellular communications
network through a dedicated channel comprising both an uplink and a
plurality of downlinks; controlling a flow of data packets by at
least one of a server function in a core network and a server in
the core network, wherein the core network does not include a base
station; and keeping up the dedicated channel after a last speech
sample packet is sent downlink from the core network by sending
post-speech packets for a time of such duration that a new uplink
can be established utilizing at least one downlink from the core
network, wherein the at least one of the server function and the
server in the core network transmits the post-speech packets to the
plurality of downlinks responsive to a packet indicating an end of
speech samples from the uplink, wherein at least one post-speech
packet includes information intended for a user of at least one
receiving terminal, and wherein post-speech packets are also sent
to a terminal that used the uplink.
2. The method according to claim 1 wherein the keeping up of the
dedicated channel comprises: the at least one of the server
function and the server determining when the last speech sample
packet is sent; the at least one of the server function and the
server sending at least one post-speech packet downlink to
receiving terminals; and determining whether a terminal taking part
in a session needs a new uplink; and establishing said new
uplink.
3. The method according to claim 2 wherein each of the receiving
terminals additionally signals the user of the terminal after
receiving the last speech sample packet.
4. The method according to claim 2 wherein said post-speech packets
are sent downlink 5 to 10 times at intervals of 500 ms at most.
5. The method according to claim 4 wherein after a last post-speech
packet the downlink used is released after a delay specific to a
cellular network.
6. The method according to claim 1 wherein the dedicated channel
used is kept up in such a manner that at least one post-speech
packet is appended to a last speech packet received by the at least
one of the server function and the server.
7. An apparatus, comprising: a control unit; and a memory including
software, where the memory and the software are configured, with
the control unit, to cause the apparatus at least to: receive a
last speech sample packet from an uplink in a cellular
communications network; and prolong an existence of downlinks by
sending post-speech packets to a plurality of downlinks for a time
of such duration that at least one new uplink can be established
from a receiving terminal, wherein the post-speech packets are sent
to the plurality of downlinks responsive to a packet indicating an
end of speech sample from the uplink, and wherein at least one of
the post-speech packets includes information intended for a user of
at least one terminal connected to the apparatus, and wherein
post-speech packets are also sent to a terminal that used the
uplink, wherein the apparatus comprises at least one of a server
function and a server in a core network associated with the
cellular communications network, wherein the core network does not
include a base station.
8. The apparatus according to claim 7, where the memory and the
software are configured, with the control unit, to cause the
apparatus to prolong the existence of a downlink by sending the
post-speech packets to the at least one terminal connected to the
apparatus.
9. The apparatus according to claim 8, where the memory and the
software are configured, with the control unit, to cause the
apparatus to send 5 to 10 post-speech packets at intervals of 500
ms at most.
10. An apparatus, comprising: a control unit; and a memory
including software, where the memory and the software are
configured, with the control unit, to cause the apparatus to at
least one of recognize or transmit post-speech packets, with at
least one of a server function in a core network and a server in
the core network, on a packet data channel responsive to a packet
indicating an end of speech samples, wherein the core network does
not include a base station, wherein at least one post-speech packet
of the post-speech packets includes information intended for a user
of at least one receiving terminal, and wherein the at least one
receiving terminal to which post speech packets are transmitted
comprises a terminal on an uplink.
11. The apparatus according to claim 10, where the memory and the
software are configured, with the control unit, to cause the
apparatus to perform signaling after receiving a last speech sample
packet.
12. The apparatus according to claim 10, where the recognized
post-speech packets are appended to speech sample packets.
13. A cellular communications network comprising: at least one
network element; and a memory including software, where the memory
and the software are configured, with the at least one network
element, to at least maintain a dedicated channel between a
plurality of terminals of the cellular communications network by
sending with the at least one network element, responsive to a last
speech packet from a sending terminal, post speech packets to a
plurality of receiving terminals for a time of such duration that a
new dedicated channel can be established utilizing said earlier
dedicated channel, wherein the at least one network element is of a
core network associated with the cellular communications network,
wherein the core network does not include a base station, wherein
at least one post-speech packet of the post-speech packets includes
information intended for a user of at least one terminal connected
to the dedicated channel, and wherein post-speech packets are also
sent to a terminal that used the uplink.
14. The cellular communications network according to claim 13,
where said dedicated channel in the cellular communications network
is maintained by sending the post-speech packets, after a last
speech packet transmitted, to the at least one terminal connected
to the dedicated channel.
15. The cellular communications network according to claim 14,
where the at least one network element is a server function in the
core network.
16. The cellular communications network according to claim 15,
where the server function is incorporated in a router server of the
core network.
17. The cellular communications network according to claim 13,
where the at least one network element comprises a terminal ending
its transmission.
18. The cellular communications network according to claim 13
wherein the dedicated channel is maintained by sending 5 to 10
post-speech packets at intervals of 500 ms at most.
19. The cellular communications network according to claim 18
wherein after a last post-speech packet said earlier dedicated
channel is arranged to be released after a delay specific to the
network.
20. A non-transitory data storage memory encoded with software
readable by a data processing device for performing actions for
continuing the existence of a dedicated channel in a
packet-switched cellular communications network, the actions
comprising: determining, with at least one of a server function and
a server in a core network associated with the packet-switched
cellular communications network, when a last speech sample packet
is sent uplink and sending at least one post-speech packet to a
plurality of receiving terminals responsive to the last speech
sample packet, wherein the core network does not include a base
station, wherein the at least one post-speech packet includes
information intended for a user of at least one receiving terminal
of the plurality of receiving terminals, wherein post-speech
packets are also sent to a terminal that used the uplink, and
determining whether a receiving terminal taking part in a session
needs a new uplink, and establishing said uplink.
21. A non-transitory computer readable memory encoded with a
computer program executable by a processor to perform actions
comprising: communicating in a cellular communications network
through a dedicated channel comprising both an uplink and a
plurality of downlinks; controlling a flow of data packets by at
least one of a server function and a server in a core network
associated with the cellular communications network, wherein the
core network does not include a base station; keeping up the
dedicated channel responsive to a last speech sample packet sent
downlink from the core network by sending post-speech packets for a
time of such duration that a new uplink can be established
utilizing at least one downlink from the core network; and
transmitting the post-speech packets to the plurality of downlinks
after receiving a packet indicating an end of speech sample from
the uplink, wherein at least one post-speech packet of the
post-speech packets includes information intended for a user of a
receiving terminal connected to the dedicated channel, and wherein
post-speech packets are also sent to a terminal that used the
uplink.
22. The computer readable memory encoded with a computer program
according to claim 21, wherein the keeping up of the dedicated
channel comprises: determining when the last speech sample packet
is sent; sending the at least one post-speech packet downlink to
receiving terminals; determining whether the receiving terminal
taking part in a session needs a new uplink; and establishing said
new uplink.
23. The computer readable memory encoded with a computer program
according to claim 22, wherein each of the receiving terminals
additionally signals a user of the terminal after receiving the
last speech sample packet.
24. The computer readable memory encoded with a computer program
according to claim 22 wherein said post-speech packets are sent
downlink 5 to 10 times at intervals of 500 ms at most.
25. The computer readable memory encoded with a computer program
according to claim 24 wherein after a last post-speech packet the
downlink used is released after a delay specific to the cellular
communications network.
26. The computer readable memory encoded with a computer program
according to claim 21 wherein the dedicated channel used is kept up
in such a manner that at least one post-speech packet is appended
to a last speech packet received by the at least one of the server
function and the server.
.Iadd.27. An apparatus, comprising: a control unit; and a memory
including software, where the memory and the software are
configured, with the control unit, to cause the apparatus to:
receive post-speech packets from at least one of a server function
in a core network and a server in the core network, wherein the
core network does not include a base station; send at least one
packet indicating an end of speech samples towards the at least one
of the server function and the server in the core network, wherein
at least one post-speech packet of the post-speech packets includes
information intended for a user of at least one receiving terminal,
wherein the sending of the at least one packet is indicative of a
time that a new dedicated channel can be established by at least
one user equipment..Iaddend.
.Iadd.28. The apparatus according to claim 27, wherein the at least
one packet comprises an indication to the at least one receiving
terminal of the end of speech samples..Iaddend.
.Iadd.29. A method, comprising: receiving post-speech packets from
at least one of a server function in a core network and a server in
the core network, wherein the core network does not include a base
station; sending at least one packet indicating an end of speech
samples towards the at least one of the server function and the
server in the core network, wherein at least one post-speech packet
of the post-speech packets includes information intended for a user
of at least one receiving terminal, wherein the sending of the at
least one packet is indicative of a time that a new dedicated
channel can be established by at least one user
equipment..Iaddend.
.Iadd.30. The method according to claim 29, wherein the at least
one packet comprises an indication to the at least one receiving
terminal of the end of speech samples..Iaddend.
.Iadd.31. An apparatus, comprising: a control unit; and a memory
including software, where the memory and the software are
configured, with the control unit, to cause the apparatus to:
receive post-speech packets from at least one of a server function
in a core network and a server in the core network, wherein the
core network does not include a base station; send at least one
packet indicating an end of speech samples towards at least one
receiving terminal, wherein at least one post-speech packet of the
post-speech packets includes information intended for a user of the
at least one receiving terminal, wherein the at least one packet
comprises an indication to the at least one receiving terminal of a
time that a new dedicated channel can be established by at least
one user equipment, wherein the sending of the at least one packet
is indicative of a time that a new dedicated channel can be
established by at least one user equipment..Iaddend.
.Iadd.32. A method, comprising: receiving post-speech packets from
at least one of a server function in a core network and a server in
the core network, wherein the core network does not include a base
station; sending at least one packet indicating an end of speech
samples towards at least one receiving terminal, and wherein at
least one post-speech packet of the post-speech packets includes
information intended for a user of the at least one receiving
terminal, wherein the sending of the at least one packet is
indicative of a time that a new dedicated channel can be
established by at least one user equipment..Iaddend.
Description
TECHNICAL FIELD OF THE INVENTION
The invention relates to a method for creating a new
packet-switched dedicated channel carrying speech samples in a
cellular network, in which method communication occurs through a
dedicated channel comprising both an uplink and at least one
downlink and, in the core network interconnecting them, a server
function/server controlling the flow of data packets. The invention
also relates to a cellular network utilizing the method, a
server/server function which realizes the method in the cellular
network, a terminal utilizing the method in the cellular network,
and a software means to implement the method.
BACKGROUND ART OF THE INVENTION
Circuit-switched voice connections over various telephone networks
have been commonplace for over 100 years. With modern technology,
people communicating over a voice connection can speak and listen
to one another simultaneously because the communications connection
is open in both directions continuously. As one party stops
speaking, the other can continue at any point of time because the
circuit-switched connection remains active all the time. The
connection is terminated only when the parties so decide.
Communications connections, including voice connections, are
increasingly packet-switched connections, like Internet
connections, instead of being circuit-switched ones. One such
packet-switched service/network is the GPRS (General Packet Radio
Service) intended primarily for data communications. In a GPRS
network, a communications connection is established only when there
is data to transmit. An individual communications connection
operates only in one direction at a time, either downlink towards
the terminal, or uplink towards the backbone network. When no more
data need to be transmitted or when there are momentarily no more
packets to send, the link is disconnected. The packet-switched
network can delay the removal of the link for a little time,
typically for a: few hundred milliseconds. This is wise if packet
transmission of newly arrived packets is to be continued or if a
communications link in the other direction is to be established
immediately after transmission in the previous direction ceases.
The transmission of newly arrived packets or establishment of a new
communications link in the other direction is quicker if the
dedicated channel reserved for the previous communications link is
still available, as opposed to that a new communications link has
to be established from scratch through a common control channel in
the network. In data transfer applications, the establishment of a
new communications link in the other direction usually succeeds
without problems because a computer can make a quick decision about
a new communications link. If human reaction/action is required for
the establishment of a new communications link, the arrangement
usually will not work, because the time reserved for the
decision-making is not long enough and the previous dedicated
connection will be terminated.
One possible way of handling a voice connection between two or more
persons over a packet-switched network is PoC (Push to talk over
Cellular) the procedures of which are under development and
standardization at present. The participants in a PoC session can
receive non-voice data. Speech is interactive: speakers take turns
randomly in a conversation, we can talk of discrete talk spurts. As
one person stops talking and another one starts in his turn, there
is a reaction time involved in this changeover, which may result in
a situation where the dedicated channel reserved for the previous
talk spurt is already released before the talk spurt of the other
speaker starts. The release of the previous dedicated channel takes
a few hundred milliseconds. After that, the dedicated channel
needed must be established through a slower procedure by first
employing the common control channel of the cellular network. This
takes several hundred milliseconds. A similar problem occurs in
conjunction with continuation of speech after a talk spurt. If the
speaker wants to continue speaking and the link to the network has
already been released, a new link must be established using the
common control channel. If the release of the link is delayed,
continuation of speech can occur more smoothly by just inserting
new packets in the transmit buffer.
FIG. 1a shows an example case in which a terminal is receiving
voice packets 1a, 2a and 3a. The voice packets end at packet 3a.
After that, in a few hundred milliseconds, 4a, the dedicated
channel is released. If the user of this terminal starts to speak
only after that, which is probable, considering human reaction
time, a new dedicated channel has to be set up for the terminal.
The delay in setting up this new dedicated channel in accordance
with the prior art is perceived by the users of terminals as an
undesirable delay.
SUMMARY OF THE INVENTION
An object of the invention is to provide a procedure through which,
in packet-switched cellular networks in which a dedicated channel
is maintained only for connections having traffic, the
establishment of a new voice communications connection can be
speeded up after the end of a received talk spurt and in the case
of a speaker continuing to speak. In the procedure according to the
invention, the removal of the dedicated channel is delayed after a
completed talk spurt so that the other party (the party that had
been listening) will have time to react to the end of the talk
spurt of the other speaker before the dedicated channel is
released. This way, the voice connection needed in t the other
transmission direction will be established through said dedicated
channel much faster than by using a common control channel in a
connection set-up procedure. The procedure according to the
invention also facilitates quicker continuation of speech in the
case where the transmitting party wants to go on speaking. Then, as
the link is still up, the new packets to be transmitted can be sent
out to the transmission path direct, without a separate
request.
The objects of the present invention are achieved by a method in
which post-speech packets according to the invention are
transmitted on a given dedicated channel of a packet-switched
network after the end of a talk spurt of a voice connection. These
post-speech packets advantageously increase the time available to
both the transmitting and listening party for reacting, so that
more likely they will have time to start their talk spurt before
the dedicated channel is released. This dedicated channel, which
was already in use, can thus be utilized to start the establishment
of a link for transmission in a new direction or to continue the
speech transmission from the previous speaker.
An advantage of the invention is that it can be used to speed up
the establishment, after a talk spurt, of a dedicated channel to be
set up in the other transmission direction for calls made in
packet-switched networks, as well as to speed up the continuation
of speech by the previous speaker.
Another advantage of the invention is that the post-speech packets
according to the invention can convey other information concerning
the current call or session to the participants.
The invention is characterized by that which is specified in the
independent claims.
Some preferred embodiments of the invention are specified in the
dependent claims.
The basic idea of the invention is as follows: When using a
packet-switched cellular network in which a dedicated channel is
maintained only for connections having traffic for voice
communication between two or more people, post-speech packets
according to the invention are appended after each talk spurt to
the data packets sent to the listening party. These post-speech
packets increase the up-time of the dedicated channel so that the
sender will have more time to react and continue his current turn
to speak and the recipient will have more time to react to the end
of the talk spurt from the previous speaker. Now, the second
speaker can start his talk spurt at a moment when the setting up of
the new link, in the opposite direction, still can be done through
the dedicated channel used by the previous link. The setting up of
the new link need not now be started by first contacting the common
control channel of the cellular network which always increases the
delay involved in the establishment of a connection. Post-speech
packets can be advantageously inserted in the data stream by an
element in the core network. Advantageously these post-speech
packets may include any additional information needed by users of
the voice connection.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described in detail below. The description
refers to the accompanying drawings in which
FIG. 1a shows an exemplary time chart describing the release of a
dedicated channel according to the prior art,
FIG. 1b shows, as an example, a packet-switched cellular
network,
FIG. 1c shows an exemplary time chart describing the release of a
dedicated channel according to the invention,
FIG. 2 shows an exemplary flow chart describing the utilization of
the method according to the invention, and
FIG. 3 shows, as an example, a cellular terminal capable of
employing the method according to the invention.
DETAILED DESCRIPTION
FIG. 1b shows, as an example, a cellular network 10 utilizing
packet-switched communication. The network described in FIG. 1b may
be a GPRS network, for instance. The network includes terminals 15,
16, 17 and 18 which communicate, when required, through a dedicated
radio channel 14a, 14b, 14c and 14d with a base station BS 13a, 13b
and 13c in the cellular network. In addition to base stations BS
the network further includes other elements 11. An exemplary
network element 11 shown in FIG. 1b advantageously comprises
exchanges, nodes and various registers. Moreover, the element 11
may comprise elements 12 realizing different server functions
either as standalone units or as parts of some other element in the
network.
In the example illustrated in FIG. 1b, advantageously at least two
terminals, e.g. terminals 15 and 18, are communicating with each
other. The communication connection used by them may be e.g. a PoC
session in a GPRS network. In this example, terminal 15 is the
transmitting terminal, and terminal 18 is the receiving terminal.
There may be, however, more terminals, such as terminals 16 and 17,
connected to the same session. In the example of FIG. 1b,
communication involves at least transmission of speech samples from
the transmitting terminal 15 to the receiving terminal 18. From the
transmitting terminal 15 an uplink 14a has been set up to the
serving base station 13a. From the base station 13a speech samples
are taken via a server element 12, which is one of the network
elements 11, to a base station 13c serving the receiving terminal
18, from which base station 13c there is a downlink 14d to the
receiving terminal 18.
The invention concerns a situation in which the speech samples from
the transmitting terminal 15 come to an end. Advantageously the
transmitting terminal 15 sends after the last speech sample some
additional packets which indicate that the speech sample ended. In
operation according to the prior art, all dedicated channels/links
14a and 14d are released according to a Temporary Block Flow (TBF)
procedure, as shown in FIG. 1a. Now, if terminal 18, for example,
needs to send speech samples after the release of the dedicated
channel, a new dedicated channel has to be established through the
common control channel which in this example includes a new uplink
from terminal 18 and a new downlink to terminal 15. These link
set-ups require several hundred milliseconds per link, which time
may be noticeable to the users as an inconvenient delay.
A method according to a first embodiment of the invention speeds up
and improves the establishment of a new dedicated channel in a
manner described in FIG. 1c. A server element 12 which may be part
of any component 11 in the core network, participates in the
transmission of data packets 1b, 2b, 3b by directing them from the
sender 15 to the recipient 18. Such an intermediate server element
12 may be a router server, for example. This server/server element
12 notices that after the speech packets 1b, 2b, 3b terminal 15
sent a supplementary packet 5 indicating an end of speech samples.
Then the router server 12 advantageously appends post-speech
packets 6 according to the invention to said supplementary packets
to extend the up-time of the dedicated channel used The post-speech
packets 6 advantageously contain some information which either
controls or helps the operation of terminals participating in the
session. Naturally, the post-speech packets 6 may be just simple
dummy packets. However, these post-speech packets 6 always have to
be distinguishable from the actual received speech samples at the
recipient's terminal.
The router server 12 in the core network transmits post-speech
packets according to the invention advantageously for a time so
long that the TBF link removal delay and the post-speech packets
according to the invention together make a delay of about 2 to 3
seconds before the (downlink) dedicated communication channel is
released, reference designator 4b. In practice this means that
post-speech packets according to the invention are transmitted for
1 to 2 seconds. If the TBF procedure terminates the dedicated
channel after about 600 ms from the last transmitted data packet,
then in the method according to the invention there has to be sent
5 to 10 post-speech packets according to the invention at intervals
of 500 to 600 ms. The dedicated channel will thus not be released
and it can be used in establishing the dedicated channel in the
other, uplink, direction.
The setting-up of a new dedicated channel can be started after the
time point represented by reference designator 7 in FIG. 1c because
it is then that the receiving terminal 18 is signaled about the end
of speech packets. Using the method according to the invention the
establishment of the dedicated channel in the other link direction
is completed at a time point marked by reference designator 8,
about 200 to 300 ms from the moment that the receiving party
responded to the end of reception.
The receiving terminal, in this example terminal 18, can
distinguish between the received supplementary packets 5 and
post-speech packets 6 on the one hand and the speech sample packets
1b, 2b, 3b on the other hand. Advantageously the terminal 18 gives
an audio signal to the user after packet 5 which indicates the end
of speech, at a point indicated by reference designator 7. However,
with the method according to the invention, the downlink 14d
remains functional for a time of such duration, reference
designator 4b, that the user of the terminal 18 has time to start
his talk spurt before the downlink 14d is removed. Therefore, the
setting-up time of the uplink to be established can be shortened by
utilizing this downlink, about 200 ms, reference designator 8 in
FIG. 1c.
In the method according to the invention, the router server 12 in
the core network sends post-speech packets 6 advantageously to all
terminals connected to the session, i.e. also to terminal 15 which
transmitted the speech samples 1b, 2b, 3b in this example. This is
to make sure that a link can be established from base station 13a
to terminal 15, which link can be employed in setting up a possible
new uplink from terminal 15 towards base station 13a. Preparing for
the establishment of a new uplink requires a longer delay than that
required for just ensuring the continuation of the existence of the
downlink. This is due to the fact that termination delay begins
earlier in the uplink than in the downlink and, moreover, the first
speech packets from the other terminal arrive only after a small
delay. All this time, the downlink towards the terminal that was
using the uplink must be kept up using the method according to the
invention so that the potential establishment of a new uplink can
be performed quickly.
In a method according to a second embodiment of the invention,
post-speech packets 6 according to the invention are not sent to
terminal 15 which transmitted the speech samples. In that case the
uplink 14a from terminal 15 is allowed to terminate according to
the prior art and, if necessary, a new downlink is established
towards that terminal 15 using a method according to the prior art.
There is no need to wait for the arrival of the first speech sample
packets from the new sending terminal 18 at terminal 15, but it
suffices that the new uplink from terminal 18 to base station 13c
can be established quickly in about 200 ms using the method
according to the invention. With this method it is possible, if
required, to reduce the overall delay in the method according to
the invention to keep the previous dedicated channel component, the
downlink, in use.
In a method according to a third embodiment of the invention,
post-speech packets 6 are added already at the sending terminal 15.
In that case few changes are needed in the operation of the network
and it can operate according to the prior art and convey the
transmitted packets from a terminal to another unchanged. The
receiving terminals 16, 17 and 18 operate in a manner described in
conjunction with the first embodiment, i.e. they can differentiate
between the post-speech packets 6 and the speech sample packets 1b,
2b, 3b.
FIG. 2 shows in an exemplary flow chart the main stages of the
method according to the invention. The exemplary flow chart in FIG.
2 mainly describes a method according to the first and second
embodiments of the invention. Initially, state 21, a downlink has
been established from the network 10 to a terminal. A server/server
element 12, such as router server, in the core network sends
forward in step 22 a data packet, such as packet 1b in FIG. 1c,
received from another terminal. In step 23 it is checked whether
this is the final data packet received from said another terminal.
If not, the process returns to step 22 where the network server 12
sends forward the next data packet, packet 2b in the example of
FIG. 1c.
At some point of time the router server 12 sends forward a speech
sample packet which indicates that speech samples from the
aforementioned another terminal are now exhausted. In the example
of FIG. 1c this means the supplementary packet 5. Having received
this supplementary packet 5 the server 12 observes the situation
and starts advantageously two separate processes.
The first process is as follows. Post-speech packets 6 according to
the invention are appended by the router server 12 to the
transmitted speech sample packets so as to produce a delay of
desired length, step 24. This keeps at least the downlink towards
the receiving terminal in existence. It is also possible to have
post-speech packets according to the invention sent also to the
terminal from which the data packets proper originated. In that
case the uplink also remains in existence.
In both of these options the server sends advantageously 5 to 10
post-speech packets 6 according to the invention at about 500-ms
intervals. This produces a sufficient delay after the last speech
sample packet 3b proper, prior to the release of the links used,
which in FIG. 1c refers to the point of time 4b. When about 600
milliseconds have passed after the transmission of the last
post-speech packet according to the invention, the links used are
released in a procedure according to the prior art, step 25.
Simultaneously with the first process, a second process is
advantageously started as well. In that process it is determined,
in step 26, whether some terminal, which earlier had been receiving
only, needs an uplink. If not, nothing needs to be done, and the
process ends up at step 25 in which the links used are released.
If, however, it is found out in step 26 that a terminal needs an
uplink, that uplink can be set up utilizing the still-functional
downlink towards said terminal. This has been accomplished at a
point of time 8 in the example of FIG. 1c. This way, the new uplink
is established in about 200 ms from the moment at which it was
detected that it is needed. Thus the process conies to step 28 in
which a new uplink is functional between a given terminal and the
network.
In the method according to a third embodiment of the invention
steps 23 and 24 are performed already at the transmitting terminal.
Thus the network serves only as a relay element between two or more
terminals, and the server function described above need not be
utilized just for the invention.
FIG. 3 shows, as an example, the main component parts of a wireless
terminal 30 in an arrangement according to the invention. The
terminal 30 utilizes an antenna 31 in the transmission and
reception of packets. Reference designator 32 represents the means
constituting a receiver RX by which the wireless terminal 30
receives packets from a cellular network 10. The receiver RX
comprises means according to the prior art for all received
packets.
Reference designator 33 represents the means that constitute the
transmitter TX in the wireless terminal. The transmitter means 33
perform on the signal to be transmitted all the necessary signal
processing measures required when communicating with a cellular
network 10.
From the point of view of the invention, the crucial functional
unit in the terminal is the control unit 34 which controls the
operation of the terminal 30. It controls the operation of all the
main component parts belonging to the terminal 30. It controls both
reception and transmission. It is further used to control the user
interface UI 36 and the memory 35. In the arrangement according to
the invention, the control unit 34 determines whether it is data
packets containing speech samples or post-speech packets according
to the invention that are received at a given moment. Furthermore,
it is the control unit 34 that decodes the received post-speech
packets according to the invention if they convey information to
the user of the terminal. If, in accordance with the third
embodiment of the invention, post-speech packets are appended to
the speech sample data packets already at the terminal, this
procedure is controlled by the control unit 34.
The software application required by the control unit 34 in the
decoding and transmission of packets according to the invention
advantageously resides in the memory 35.
The user interface UI 36 is utilized in controlling the functions
of the terminal.
On the network 10 side, operation according to the invention is
maintained by a server/server function 12. The software application
required for the method according to the invention is
advantageously stored at a router server 12.
Some preferred embodiments according to the invention were
described above. The invention is not limited to the embodiments
just described. The inventional idea can be applied in numerous
ways within the scope defined by the attached claims.
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