U.S. patent application number 16/195075 was filed with the patent office on 2019-07-25 for communicating on a shared channel in a wireless network.
This patent application is currently assigned to Intellectual Ventures Holding 81 LLC. The applicant listed for this patent is Intellectual Ventures Holding 81 LLC. Invention is credited to Martin Warwick Beale.
Application Number | 20190230640 16/195075 |
Document ID | / |
Family ID | 40363942 |
Filed Date | 2019-07-25 |
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United States Patent
Application |
20190230640 |
Kind Code |
A1 |
Beale; Martin Warwick |
July 25, 2019 |
COMMUNICATING ON A SHARED CHANNEL IN A WIRELESS NETWORK
Abstract
A user equipment (UE) may receive a broadcast channel that
includes a bits indicating possible resources for a downlink shared
channel being utilized for a signaling channel. The UE may monitor,
based on the indicated possible resources, the signaling channel
for signaling information for the UE.
Inventors: |
Beale; Martin Warwick;
(Bristol, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Intellectual Ventures Holding 81 LLC |
Las Vegas |
NV |
US |
|
|
Assignee: |
Intellectual Ventures Holding 81
LLC
Las Vegas
NV
|
Family ID: |
40363942 |
Appl. No.: |
16/195075 |
Filed: |
November 19, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
15611309 |
Jun 1, 2017 |
10136416 |
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16195075 |
|
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13212867 |
Aug 18, 2011 |
9674818 |
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15611309 |
|
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11863205 |
Sep 27, 2007 |
8027291 |
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13212867 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 72/0406 20130101;
H04W 48/10 20130101 |
International
Class: |
H04W 72/04 20060101
H04W072/04 |
Claims
1.-17. (canceled)
18. A user equipment (UE) comprising: a receiver configured to
receive broadcast information including a plurality of bits,
wherein the plurality of bits indicates physical shared channel
resources in a slot utilized for a plurality of signaling channels;
and a processor, communicatively coupled to the receiver,
configured to monitor the plurality of signaling channels in the
slot, to determine whether signaling information for the UE is
present based on an identification of the UE, and to process the
signaling information in response to the determination that
signaling information for the UE is present.
19. The UE of claim 18, wherein the broadcast information is
received on a broadcast channel.
20. The UE of claim 19, wherein the plurality of bits are a part of
a data portion of the broadcast channel.
21. The UE claim 18, wherein the UE powers down radio circuitry
outside of the physical shared channel resources.
22. The UE of claim 18, wherein the identification of the UE is
assigned by a network device to decode the signaling
information.
23. The UE of claim 18, wherein a number of the plurality of bits
is constrained.
24. The UE of claim 18, wherein on a condition that the UE is
assigned physical shared channel resources that overlap with the
indicated physical shared channel resources, the processor is
configured to not receive the assigned physical shared channel
resources that overlap.
25. A method performed by a user equipment (UE), the method
comprising: receiving, by the UE, broadcast information including a
plurality of bits, wherein the plurality of bits indicates physical
shared channel resources in a slot utilized for a plurality of
signaling channels; monitoring, by the UE, the plurality of
signaling channels in the slot; determining, by the UE, whether
signaling information for the UE is present based on an
identification of the UE; and processing, by the UE, the signaling
information in response to the determination that signaling
information for the UE is present.
26. The method of claim 25, wherein the broadcast information is
received on a broadcast channel.
27. The method of claim 26, wherein the plurality of bits are a
part of a data portion of the broadcast channel.
28. The method of claim 25, wherein the UE powers down radio
circuitry outside of the physical shared channel resources.
29. The method claim 25, wherein the identification of the UE is
assigned by a network device to decode the signaling
information.
30. The method claim 25, wherein a number of the plurality of bits
is constrained.
31. The method of claim 25, wherein on a condition that the UE is
assigned physical shared channel resources that overlap with the
indicated physical shared channel resources, not receiving the
assigned physical shared channel resources that overlap.
32. A network device comprising: a transmitter operatively coupled
to a processor, the transmitter and the processor are configured to
transmit broadcast information including a plurality of bits,
wherein the plurality of bits indicates physical shared channel
resources in a slot utilized for a plurality of signaling channels;
and the transmitter and the processor are configured to transmit to
a user equipment (UE) a signaling channel in the slot including
signaling information for the UE, wherein the signaling channel
transmission to the UE is derived from an identification of the
UE.
33. The network device of claim 32, wherein the broadcast
information is transmitted on a broadcast channel.
34. The network device of claim 33, wherein the plurality of bits
are a part of a data portion of the broadcast channel.
35. The network device of claim 32, wherein the transmitter and the
processor transmit the identification of the UE to the UE.
36. The network device of claim 32, wherein the processor is
configured to assign the UE physical shared channel resources that
overlap with the indicated physical shared channel resources.
37. A user equipment (UE) comprising: a receiver configured to
receive information including a plurality of bits, wherein each of
the plurality of bits indicates a respective time interval that
physical shared channel resources are utilized for signaling
channels; and a processor, communicatively coupled to the receiver,
configured to monitor the signaling channels in indicated time
intervals, to determine whether signaling information for the UE is
present based on an identification of the UE and to process the
signaling information in response to the determination that
signaling information for the UE is present.
38. A method performed by a user equipment (UE), the method
comprising: receiving, by the UE, information including a plurality
of bits, wherein each of the plurality of bits indicates a
respective time interval that physical shared channel resources are
utilized for signaling channels; and monitoring, by the UE, the
signaling channels in indicated time intervals, to determine
whether signaling information for the UE is present based on an
identification of the UE and to process the signaling information
in response to the determination that signaling information for the
UE is present.
Description
CROSS REFERENCE TO RELATED APPLICATION(S)
[0001] This application is a continuation of U.S. patent
application Ser. No. 15/611,309, filed Jun. 1, 2017, which is a
continuation of U.S. patent application Ser. No. 13/212,867, filed
Aug. 18, 2011, which issued as U.S. Pat. No. 9,674,818 on Jun. 6,
2017, which is a continuation of U.S. patent application Ser. No.
11/863,205, filed Sep. 27, 2007, which issued as U.S. Pat. No.
8,027,291 on Sep. 27, 2011, which are incorporated by reference as
if fully set forth.
FIELD OF THE INVENTION
[0002] The field of the invention relates, in general, to a method
and apparatus for transmitting transport channels over a physical
channel of a cellular communication system. In particular, but not
exclusively, the field of the invention relates to allocating
channel resources within a physical channel of a cellular
communication system.
BACKGROUND OF THE INVENTION
[0003] Known cellular communication systems, such as a Universal
Mobile Telecommunications System (UMTS) Radio Access Network
(UTRAN), standardised by the 3rd Generation Partnership Project
(3GPP), typically consist of a set of radio network controllers
(RNCs), Node B, also known as Node-Bs, and mobile stations (MSs),
also known as User Equipment (UEs). FIG. 1 illustrates an example
of a known network topology for part of such a cellular
communication system 100.
[0004] The RNCs 105 provide a connection with, for example, a Media
Gateway (not shown), which acts as a translation unit between, in
this case, the UMTS network and, for example, a Public Switched
Telephone Network (PSTN). The RNC 105 also performs some of the
higher layer processing for the UMTS network, performing functions,
such as, setting up and managing radio bearers, radio resource
management, supporting mobility, controlling initial access of UEs
to the communication system, radio link control (RLC), etc.
[0005] The Node Bs 110 typically perform lower layer processing for
the network, performing such functions as Medium Access Control
(MAC), formatting blocks of data for transmission and physically
transmitting transport blocks to UEs.
[0006] As can be seen in FIG. 1, Node Bs 110 are connected to an
RNC 105 via an interface (Iub) 115. This interface between a Node B
110 and an RNC 105 may be a leased line, for example provided by a
fixed line telecommunications provider, a microwave link, an
Ethernet cable or some other form of communication link. The Node
Bs are connected wirelessly to the UEs 120.
[0007] In order to conserve battery life, when a UE 120 is not
involved in active connections, it is known for the UE 120 to go
into an idle state, whereby the UE powers down its radio frequency
circuitry (RF). When a UE 120 is in the idle state, it is important
to allow the Node B to initiate a connection to the UE 120, for
example when there is an in-coming call for the UE 120.
[0008] In order to achieve this, it is known for a UE 120 to
periodically power up its radio circuitry in order to monitor
specific channels in order to determine whether it is required to
establish a connection with the network. UMTS provides two services
with which a Node B is able to indicate to a specific UE 120 that
it is required to establish a connection with the network. One is
termed a Paging CHannel (PCH) and the other is termed a Forward
Access CHannel (FACH). Details of these and other services are
provided in 3GPP TS 25 221 (Universal Mobile Telecommunications
System (UMTS); Physical channels and mapping of transport channels
onto physical channels (TDD)) and other documents referenced
therein.
[0009] The PCH is a downlink transport channel that is used to
carry control information to a UE when the network does not know
the specific location of the UE, i.e. the specific Node B to which
the UE is attached.
[0010] In the known art, the PCH comprises two blocks: the Paging
Indicator CHannel (PICH) and the PCH itself. The PICH comprises
multiple indicator bits. Each UE is associated with one of the
indicator bits within the PICH. Accordingly, when the UE is paged
by the network using the PCH, the network sets the relevant
indicator bit in the PICH. When in the idle state, the UE
periodically decodes the PICH to see if the indicator bit with
which it is associated has been set. If the relevant indicator has
been set, the UE then reads the PCH.
[0011] Each UE has a unique identifier (UE-ID). When the network
pages a UE, as previously mentioned, the network sets the relevant
indicator within the PICH for that UE, and transmits the UE-ID for
the UE being paged, and the relevant message within the PCH. In
this manner, since more than one UE may be associated with an
indicator bit in the PICH, the UE-ID enables a UE to determine
whether the message is intended for that UE or not. If the PCH
contains the UE-ID for the UE, the UE then reads the message, and
performs the required actions. Thus, in the known art, the
indicator bits are used in a paging channel to inform the UE
whether it needs to turn its radio on for reading the PCH (i.e. as
a battery saving mode).
[0012] The UMTS standard dictates that the PCH (and PICH) are
always transmitted at a reference power level.
[0013] In a wireless communications system, the communication
medium is divided into units of resource. A unit of resource can be
a single code (e.g. UMTS FDD), a plurality of codes, a set of codes
and timeslots (e.g. UMTS TDD), a set of timeslots (e.g. a TDD
system) or a set of tones, tones and symbols or tones, symbols and
timeslots (e.g. an OFDM system).
[0014] The FACH is a downlink transport channel that is used to
carry control information to a UE when the system knows the
location cell of the UE, e.g. the specific Node B to which the UE
is attached. The FACH allows short messages to be sent from the
Node B to the UE. These short messages are typically control type
messages that are used, for example, to allocate physical resources
to the UE, set up dedicated physical channels, etc.
[0015] The FACH is transmitted on a set of physical resources that
are pre-defined and broadcast by the Node B on a Broadcast CHannel
(BCH). The FACH is controlled by the RNC, which defines the codes
and timeslots that are reserved for FACH transmissions. The RNC
also reserves an amount of power headroom for the transmission of
the FACH. When the FACH is transmitted, the RNC defines the power
with which the FACH must be transmitted by the Node B. Power
headroom is the amount of power that the RNC reserves for
allocation of FACH resources. The power that is not reserved for
`power headroom` is allocated to the Node B to do with as it sees
fit (for example scheduling HS-DSCH resource into). Thus, when the
RNC allocates power headroom, it informs the Node B that the Node B
cannot allocate that power headroom, as the power headroom is
reserved by the RNC for the RNC to allocate resource into.
[0016] Unlike the PCH (and PICH), the FACH is not required to
always be transmitted, and typically is only used when a message is
required to be sent to a UE.
[0017] FIG. 2 illustrates a high level signal flow example 200 of
an implementation for FACH transmissions. An RNC sends a `NODE B
SETUP` message to a Node B, instructing the Node B to reserve a
certain set of codes and timeslots for FACH transmissions. This
message may also reserve power headroom for use by the RNC. In
UMTS, the `NODE B SETUP` message for configuring the FACH transport
channel is the `COMMON TRANSPORT CHANNEL SETUP` message, sent to
the Node B over the Iub interface 115.
[0018] The Node B 110 then periodically transmits a `SYSTEM
INFORMATION` message 210 on the Broadcast CHannel (BCH). This
SYSTEM INFORMATION message 210 informs UEs of the physical
resources used for FACH transmissions, such as the codes and
timeslots in a Code Division Multiple Access (CDMA) system or the
sub-carriers and timeslots in an Orthogonal Frequency-Division
Multiplexing (OFDM) system. The SYSTEM INFORMATION message 210
typically also contains other broadcast information relevant to
that cell, such as the network identity etc.
[0019] A UE 120 is able to receive the SYSTEM INFORMATION message
210, and configure its FACH decoding function based on the
information contained within the SYSTEM INFORMATION message
210.
[0020] When the RNC 105 needs to send a message to a UE 120 using
the FACH, the RNC sends a `SEND FACH` message 215 to the Node B. In
UMTS, the `SEND FACH` message is carried using FACH frame protocol
(FACH FP) messages over the Iub interface 115. The SEND FACH
message 215 defines the specific code and timeslot to be used for
the FACH transmission 220 from the Node B 110 to the UE 120, as
well as the power level to be applied to the FACH transmission, the
message contents and the identity of the UE (the UE-ID) that are to
be included in the FACH transmission. The Node B 110 subsequently
transmits the FACH message 220 to the UE 120, as defined by the RNC
105 in the SEND FACH message 215.
[0021] The UE 120 decodes the FACH 220 every frame, according to
the definition of the FACH provided within the SYSTEM INFORMATION
message 210. If the UE-ID in the FACH message 220 matches the
identity that has been assigned to the UE 120, the UE 120 acts on
the message contents in the FACH 220.
[0022] FIG. 3 illustrates an example of a known assignment of
physical resources 300 for a single Time Division Duplex (TDD)
system, and shows that one timeslot per frame is assigned for FACH
usage. As previously mentioned, the physical resources 300 for the
FACH are pre-assigned by the RNC 105, in the NODE B SETUP message
205, and cannot be reused by other channels. Even when the FACH is
lightly used, for example when most UEs are in a connected state,
receiving data traffic on a traffic channel, indicated as a High
Speed Downlink Shared Channel (HS-DSCH) 305 in FIG. 3, the FACH
timeslot 310 is still required to be reserved.
[0023] As will be appreciated by a skilled artisan, the fact that
the FACH timeslot 310 is required to be reserved, particularly
during light use of the FACH, is an inefficient use of physical
resources. Consequently, the inventor of the present invention has
recognised and appreciated that it is desirable for the timeslot
310 assigned to the FACH to be able to be used for other purposes
when it is not required for the transmission of FACH messages. For
the example illustrated in FIG. 3, the traffic channel resources,
namely the HS-DSCH resources 305, comprise seven timeslots. If the
timeslot 310 reserved for FACH transmissions could be utilised for
a traffic channel during periods when no FACH transmissions were
required to be sent, the traffic channel resources could be
increased from seven timeslots to eight timeslots. This would
increase the traffic channel resources by fourteen percent (14%)
during those periods.
[0024] A known solution for the reuse of the FACH timeslot is for
the traffic channel resources, which for the example illustrated in
FIG. 3 is in the form of the HS-DSCH 305, to be used for the
transmission of FACH messages. In this case, the information that
would have been transmitted on the FACH transport channel is
instead transmitted on the HS-DSCH transport channel. In this
solution the Node B 110, as opposed to the RNC 105, controls the
FACH, and the FACH timeslot of FIG. 3 becomes an HS-DSCH timeslot.
In this manner, in the example of FIG. 3, the HS-DSCH 305 always
comprises eight timeslots, as opposed to seven.
[0025] The HS-DSCH 305 is a shared channel that is controlled by
the Node B 110. The content of the HS-DSCH 305 is allocated via
Shared Control CHannels for the HS-DSCH (HS-SCCH) 315, which is a
downlink physical channel that carries higher layer control
information for the HS-DSCH.
[0026] The HS-SCCH 315 contains a UE-ID relating to the UE 120 for
which content within the HS-DSCH 305 is intended. The UE-ID ensures
that only that UE 120 for which the content of the HS-DSCH 305 is
intended decodes the HS-SCCH 315 successfully. The HS-SCCH 315 also
instructs the UE of those codes and timeslots that are allocated to
it for the HS-DSCH 305 transmission allocated to it, and the coding
and modulation of the HS-DSCH 305, e.g. code rate and modulation
order, such as quadrature phase shift keying (QPSK), 16-QAM
(Quadrature Amplitude Modulation), etc. Having decoded the HS-SCCH
315, the UE 120 is able to decode relevant timeslot(s) of the
HS-DSCH 305 using the information contained within the HS-SCCH 315,
and retrieve the relevant content.
[0027] When the HS-DSCH 305 is used to transmit the FACH, the codes
and timeslots that are used for the HS-SCCH 315, as well as a
FACH-ID are broadcast by the Node B, for example within the SYSTEM
INFORMATION message 210 illustrated in FIG. 2. UEs that are
required to monitor the FACH subsequently attempt to decode the
HS-SCCH 315 using the FACH-ID. If a UE 120 is successful in
decoding the HS-SCCH 315 using the FACH-ID, a FACH message is
present within the HS-DSCH 315.
[0028] Having decoded the HS-SCCH 315 using the FACH-ID, the UE 120
then decodes the relevant part of the HS-DSCH 305 as allocated by
the HS-SCCH 315, and using the information provided within the
HS-SCCH 315.
[0029] The UE-ID of the relevant UE 120 is included with the
HS-DSCH 305. If this matches the UE-ID of the UE 120 decoding the
HS-DSCH 305, the UE 120 acts on the FACH message contents in the
HS-DSCH 305.
[0030] When a FACH message is to be sent to a UE 120, the RNC 105
requests the Node B 110 to send a FACH to a UE 120 with a certain
message. The Node B 110 then schedules the transmission of the FACH
message in the HS-DSCH 305, along with any traffic data that is to
be sent in the HS-DSCH 305. The Node B 110 chooses the codes and
timeslots that are to be used for the HS-DSCH 305 carrying the FACH
message, as well as the coding and modulation to be applied to the
HS-DSCH 305. The Node B then transmits an HS-SCCH 315 that
allocates the codes and timeslots on the HS-DSCH 305 for the FACH
message, along with the coding and modulation used, and encodes the
HS-SCCH 315 using the FACH-ID.
[0031] When there are no requests from the RNC 105 for the Node B
110 to transmit a FACH message, the Node B is able to use all of
the HS-DSCH 305 resource for traffic data. In this manner, physical
resources are used more efficiently, and in particular physical
resources are not permanently assigned for transmitting FACH
messages, in particular when no, or few, FACH messages are required
to be transmitted.
[0032] However, a problem with this known technique for reusing the
FACH timeslot is that it requires the use of the HS-SCCH 315 and
the HS-DSCH 305 channels for transmitting FACH messages, as opposed
to just a FACH channel, and as such carries a penalty in terms of
power consumption.
[0033] FACH messages may be transmitted to a UE 120 when the UE is
in an idle state (or alternatively in a connected state).
Accordingly, the Node B 110 is unaware of the state of the
transmission path between itself and the UE 120. As a result,
normal power control is ineffective since the Node B 110 has no
information with which to make an informed decision on the
appropriate power level to use. Consequently, the power
requirements must initially depend on the number of bits to be
transmitted, and the coding rate, without explicit knowledge of the
path loss between the UE and Node B.
[0034] A number of bits transmitted on the HS-SCCH 315 is
comparable to a number of bits that are transmitted on a
traditional FACH, in the order of 60 bits (57 bits for a 3.84 Mcps
TDD HS-SCCH). The exact number of bits to be transmitted on the
FACH depends on the particular implementation. The power
requirements for HS-SCCH 315 and FACH at the start of a connection
are therefore substantially the same, due to the similar number of
bits to be carried on each channel, for example approximately 33%
of the Node B transmit power.
[0035] A problem with this known technique for reusing the FACH
timeslot is that both the HS-SSCH 315 and the HS-DSCH 305 must be
used in order to transmit a FACH message, each requiring
approximately 33% of the Node B transmit power, albeit in different
timeslots. This is in contrast to the traditional method of
transmitting FACH messages, where using the dedicated FACH timeslot
only required the one timeslot. Thus, the known technique for
reusing the FACH timeslot requires an additional timeslot at 33% of
the Node B transmit power.
[0036] A skilled artisan will appreciate that, although the reuse
of the FACH timeslot by mapping the FACH onto HS-DSCH resources
provides a considerable improvement in the use of the physical
resources, this increase in the power requirements is
undesirable.
SUMMARY OF THE INVENTION
[0037] Accordingly, the invention seeks to mitigate, alleviate or
eliminate one or more of the abovementioned disadvantages, singly
or in any combination.
[0038] According to a first aspect of the invention, there is
provided a cellular communication network node comprising a
transmitter operably coupled to signal processing logic and
arranged to transmit at least one direct signalling channel
indicator bit generated by the signal processing logic. The signal
processing logic is arranged, upon receipt of a message to be
transmitted, to set at least one direct signalling channel
indicator bit to indicate that a direct signalling channel is
active in at least one unit of resource. The signal processing
logic is further arranged to reallocate the at least one unit of
resource for use by at least one other channel when no message is
required to be transmitted.
[0039] Thus, embodiments of the invention may allow improved use of
the communication resource in the communication system, for example
by allowing physical resource to be dynamically switched between
different channel types.
[0040] According to an optional feature of the invention, the
signal processing logic may be arranged to generate direct
signalling channel resource information comprising a description of
the physical resources and transport formats applied to the direct
signalling channel(s). Thus, embodiments of the invention may allow
the physical resources of the direct signalling channel to be
transmitted relatively infrequently to all UEs. Thus, in this
manner, a reduction in the signalling load is provided, as compared
to the classic case where the physical resources for the direct
signalling channel are sent whenever the direct signalling channel
is allocated.
[0041] According to an optional feature of the invention, the
signal processing logic may be arranged, upon receipt of a message
to be transmitted, to set the at least one direct signalling
channel indicator bit in a first frame, and to transmit the message
in a second frame. For example, the second frame may be a next
consecutive frame to the first frame. Thus, embodiments of the
invention may allow the UE to have a longer time to process the
indicator bit, thereby allowing the UE complexity to be reduced
and/or to allow the UE to turn its receiver off in the time during
which the direct signalling channel is transmitted.
[0042] According to an optional feature of the invention, the
signal processing logic may allocate a plurality of direct
signalling channels to at least one unit of resource. Thus,
embodiments of the invention may allow the system to operate with a
reduced number of direct signalling channel indicator bits. The
bits that are freed up on the indicator channel may then be used
for other indication purposes (e.g. paging or E-DCH ACK/NACK
signalling).
[0043] According to an optional feature of the invention, the
signal processing logic may generate a single direct signalling
channel indicator bit for transmission, or a plurality of direct
signalling channel indicator bits, one for each direct signalling
channel, or a number of indicator bits for transmission, where each
indicator bit corresponds to a plurality of direct signalling
channels. Thus, embodiments of the invention may allow for finer
granularity control of the allocated direct signalling channel, for
example the network may allocate some of the resource as direct
signalling channel instead of either allocating all or none of the
resource. This allows for more targeted allocation of resource to
direct signalling channels and traffic channels (e.g. HS-DSCH).
[0044] According to an optional feature of the invention, the
signal processing logic may be arranged to allocate a plurality of
direct signalling channels to a plurality of units of resource.
Thus, embodiments of the invention may allow a single indicator bit
to control more than one direct signalling channel, thus either
allowing more direct signalling channels (when the number of
indicator bits that can be sent are constrained) or reduced usage
of the indicator bits.
[0045] According to an optional feature of the invention, the
signal processing logic, upon receipt of at least one message to be
transmitted, may be arranged to re-allocate at least one unit of
resource not required for transmitting the one or more message, for
use by at least one channel other than the direct signalling
channel. Thus, embodiments of the invention may allow better usage
of the resource, for example some of the resource may be assigned
to the direct signalling channel and some of the resource may be
reassigned to the other channel when it is not needed for the
direct signalling channel. Furthermore, the usage of the resource
may be more tailored to the traffic profile, if the direct
signalling channel is not greatly required, but there is a lot of
traffic on the traffic channel.
[0046] According to an optional feature of the invention, the at
least one direct signalling channel may be a Forward Access
Channel(s) (FACH) within a Universal Mobile Telecommunications
System (UMTS) network. For example, the at least one direct
signalling channel unit of resource may be re-allocated for use by
a High Speed Downlink Shared CHannel (HS-DSCH). Thus, embodiments
of the invention may allow direct applicability to an application.
In this case, for example, under-utilised FACH resource may be
transferred to HS-DSCH resource, thus increasing the potential
throughput of HS-DSCH.
[0047] According to an optional feature of the invention, the
signal processing logic may generate the at least one direct
signalling channel indicator bit within a Broadcast CHannel (BCH)
for broadcast. For example, the signal processing logic may locate
the at least one direct signalling channel indicator bit within a
Transport Format Combination Indicator (TFCI) type field within the
BCH. Furthermore, according to an optional feature of the
invention, the signal processing logic may generate the direct
signalling channel indicator bit(s) as part of a data portion of
the BCH for broadcast. Thus, embodiments of the invention may allow
transmission directly on the broadcast channel, thereby removing a
need for a separate indicator channel. Alternatively, when an
indicator channel naturally exists (e.g. PICH or E-HICH), the
paging or E-DCH acknowledgement capacity of those indicator
channels is not reduced, as direct signalling channel indicator
bits do not replace indicator bits that might be required for the
other functions, such as PICH or E-HICH.
[0048] According to an optional feature of the invention, the
signal processing logic may generate the at least one direct
signalling channel indicator bit within a dedicated direct
signalling channel indicator channel or within a dedicated paging
indicator channel or within a E-DCH Hybrid ARQ Indicator CHannel
(E-HICH) of a Universal Mobile Telecommunications System (UMTS)
network. Thus, embodiments of the invention may allow a reduction
in usage of the broadcast channel. In this manner, an indicator
channel may also be more lightly coded (than a broadcast channel),
thereby allowing for lower power/lower complexity decoding of the
indicator channel (compared to a case where the indicator bits are
sent on the broadcast channel).
[0049] In accordance with a second aspect of the invention there is
provided a method for transmitting transport channels over a
physical channel of a cellular communication system. The method
comprises determining whether at least one message is to be
transmitted. If it is determined that at least one message is
required to be transmitted, scheduling the at least one message for
transmission in at least one unit of resource allocated to at least
one direct signalling channel, and setting at least one direct
signalling channel indicator bit for transmission. If it is
determined that no message is to be transmitted, re-allocating at
least one unit of resource allocated for use by the at least one
direct signalling channel for use by at least one channel other
than the direct signalling channel. Thus, embodiments of the
invention may provide a more flexible usage of resources, for
example direct signalling channel resource that is under-utilised
may be re-assigned to other (e.g. traffic) channels.
[0050] In accordance with a third aspect of the invention there is
provided a computer program product comprising program code for
signalling in a wireless communication system from a network
element to a wireless communication unit. The computer program
product comprising program code for setting, upon receipt of a
message to be transmitted, at least one direct signalling channel
indicator bit. The program code further comprises code for
transmitting a message in at least one unit of resource allocated
for use as a direct signalling channel, and re-allocating the at
least one unit of resource allocated to the direct signalling
channel for use by at least one other channel when no message is
required to be transmitted. Thus, embodiments of the invention may
allow the system to run on general purpose hardware, thus reducing
cost.
[0051] In accordance with a fourth aspect of the invention there is
provided a wireless communication unit arranged to receive a
signalling message allocating a first set of resources in a
wireless communication system from a cellular communication network
node. The wireless communication unit further comprises logic for
receiving a at least one direct signalling channel indicator bit on
a communication channel, the at least one direct signalling channel
indicator bit allocating a direct signalling channel. The wireless
communication unit further comprises logic for modifying the
wireless communication unit's first set of resources in response to
a status of the at least one direct signalling channel indicator
bit.
[0052] In the existing 3GPP system, for example, whenever any
resource is applied to FACH, resources in the FACH slot and HS-DSCH
resources cannot easily be allocated to the same UE, since the
amount of resource in the FACH slot and HS-DSCH slot differ and
existing signalling restrictions mean that the same amount of
physical resource has to be allocated in each timeslot. Thus,
embodiments of the invention address this limitation and may allow
the system to allocate more resource to a UE.
[0053] In this manner, in contrast to normal 3GPP operation where
the same number of codes has to be allocated to a wireless
communication unit in all of the timeslots that it is allocated due
to signalling restrictions, the wireless communication unit is
signalled whether FACH is active. Advantageously, the wireless
communication unit is able to use this indication to modify, for
example, the HS-DSCH resource allocation, as the wireless
communication unit knows that if the FACH indicator bit was set
then any HS-DSCH resources that are common to FACH resources in the
FACH timeslot must be allocated to FACH and not to HS-DSCH.
[0054] In accordance with a fifth aspect of the invention there is
provided a method for resource allocation in a wireless
communication system by a wireless communication unit. The method
employed by the wireless communication unit comprises receiving by
a wireless communication unit a signalling message allocating a
first set of resources in a wireless communication system via at
least one direct signalling channel indicator bit on a
communication channel, the at least one direct signalling channel
indicator bit allocating a direct signalling channel; and modifying
the wireless communication unit's first set of resources in
response to a status of the at least one direct signalling channel
indicator bit.
[0055] These and other aspects, features and advantages of the
invention will be apparent from, and elucidated with reference to,
the embodiments described hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0056] FIG. 1 shows an example of a known network topology for part
of a cellular
[0057] FIG. 2 shows a high level example of a known implementation
for FACH channel transmissions.
[0058] FIG. 3 shows an example of a known assignment of physical
resources.
[0059] Embodiments of the invention will now be described, by way
of example only, with reference to the accompanying drawing(s), in
which:
[0060] FIG. 4 shows part of a cellular communication system in
accordance with embodiments of the invention.
[0061] FIG. 5 and FIG. 6 show an example of resource allocation in
accordance with embodiments of the invention.
[0062] FIG. 7 shows an example of resource allocation in accordance
with embodiments of the invention.
[0063] FIG. 8 shows an example of resource allocation in accordance
with embodiments of the invention.
[0064] FIG. 9 shows an example of resource allocation in accordance
with embodiments of the invention.
[0065] FIG. 10 shows a flowchart of a method for transmitting
transport channels over a physical channel of a cellular
communication system in accordance with embodiments of the
invention.
[0066] FIG. 11 shows a flowchart of a method for transmitting
transport channels over a physical channel of a cellular
communication system in accordance with embodiments of the
invention.
[0067] FIG. 12 illustrates a typical computing system that may be
employed to implement processing functionality in accordance with
embodiments of the invention.
DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0068] The following embodiments of the invention will be described
in a context of a Forward Access Channel (FACH) provided as part of
a Universal Mobile Telecommunications System (UMTS) communication
network, as defined in 3GPP TS 22.146 and 3GPP TS 25.221 and other
documents referenced therein. However, it will be appreciated by a
skilled artisan that the inventive concept described herein may be
applied to any direct signalling channel, such as a paging channel,
an allocation channel such as HS-SCCH or applied to alternative
comparable services.
[0069] The following embodiments of the invention will be described
in a context of timeslots, for example with respect to a TDD
implementation, but the inventive concept is equally applicable to
any communication `unit of resource`, for example for non-TDD
implementations. Thus, hereinafter the term timeslot in a TDD
context encompasses any communication `unit of resource` outside of
a TDD domain.
[0070] In one embodiment of the invention, in contrast to the known
art where the indicator bits are used in a paging channel to inform
the UE whether it needs to turn its radio on for reading the PCH
(i.e. as a battery saving mode), the indicator bits are used to
inform the UE whether it should be reading the resources `reserved`
for FACH as a FACH channel, or whether it should be ignoring those
resources (for example when they are being used for another channel
such as HS-DSCH).
[0071] Referring now to FIG. 4, there is illustrated a part of a
cellular communication network 400 according to embodiments of the
invention. The cellular communication network 400 comprises a
communication network node, which for the illustrated embodiment is
in a form of a Node B (NODE B) 410, operably coupled to a radio
network controller (RNC) 420, for example by way of a leased line
provided by a fixed line telecommunications provider, a microwave
link, an Ethernet cable or some other form of communication link.
The RNC 420 may be further operably coupled to, for example, a
Media Gateway (not shown).
[0072] The Node B 410 comprises signal processing logic 440
arranged to transmit one or more indicator bits, for example on a
broadcast channel. The signal processing logic 440 is further
arranged, upon receipt of a FACH message to be transmitted, for
example from the RNC 420, to set at least one of the one or more
indicator bits and to transmit the FACH message in at least one of
one or more timeslots allocated for use by one or more FACH
channels. The signal processing logic 440 is still further arranged
to reallocate the one or more timeslots allocated to the one or
more FACH channels, for use by one or more channels other than the
one or more FACH channels, when no FACH messages are required to be
transmitted.
[0073] The RNC 420 may, for example by way of a `NODE B SETUP`
message (e.g. `COMMON TRANSPORT CHANNEL SETUP` in UMTS), instruct
the Node B 410 those timeslot(s) that is/are to be allocated to the
FACH channel(s), along with a set of channelisation codes that is
reserved for the FACH channel(s) (codes used to separate the
different channels that may be present on a certain frequency in a
Code Division Multiple Access (CDMA) system), power headroom
reserved for the RNC, etc. In a context of a 3GPP system, the
generic expressions of `NODE B SETUP" and `SEND FACH` message may
be referred to, for example, as `COMMON TRANSPORT CHANNEL SETUP`
and `FACH frame protocol`.
[0074] Accordingly, the Node B 410 may comprise a memory element
450, in which the Node B 410 stores the settings provided by the
RNC 420.
[0075] Alternatively, the Node B 410 may define which timeslot(s)
are to be allocated to the FACH channel, along with a set of
channelisation codes that are reserved for the FACH channel(s),
power assigned to Node B FACH transmissions etc. The Node B may
then inform the RNC of these definitions.
[0076] The signal processing logic 440 of the Node B 410 is
arranged to transmit, upon receipt of a FACH message transmitted
from the RNC 420, the one or more indicator bits within, for
example, the broadcast channel. In this manner, by monitoring the
channel carrying indicator bits, e.g. the broadcast channel, the UE
430 is able to determine whether there is a FACH message. If there
is no indicator bit set, the UE 430 is able to power down its radio
circuitry until the next time the channel carrying indicator bits
is scheduled to be transmitted. If there is a FACH message, the UE
430 is able to read the contents of the FACH channel, and determine
whether, or not, the message is intended for itself, as described
in greater detail below.
[0077] Referring now to FIG. 5, there is illustrated an example of
resource allocation in accordance with embodiments of the
invention, where a FACH message is required to be transmitted. In
particular, FIG. 5 illustrates a plurality of timeslots 510 within
a 3.84 Mcps TDD UMTS frame.
[0078] The plurality of timeslots 510 are allocated to transport
channels, which for the illustrated embodiments may comprise a
Broadcast CHannel (BCH) 525, a High Speed Downlink Shared Channel
(HS-DSCH) 505, a Shared Control Channel for the HS-DSCH (HS-SCCH)
515, and a Forward Access CHannel (FACH) 520. In embodiments of the
invention, one timeslot also carries (what will hereinafter be
referred to as) an INdicator Channel (INCH) 521, carrying indicator
bits. FIG. 5 is labeled in terms of transport channels, but the
skilled artisan will appreciate that transport channels are mapped
to physical channels before transmission and that for the transport
channels illustrated there is a one-to-one mapping between
transport channel and physical channel. A skilled artisan will also
appreciate that the timings between channels as shown in FIG. 5,
and subsequent figures, are illustrative and may vary in an actual
implementation of the invention.
[0079] Furthermore, the indicator bits may be sent on any channel
used to send indicator bits, which may exist on a same timeslot as
the BCH (but can also or alternatively exist on a timeslot other
than that occupied by the broadcast channel (BCH)). For example,
such indicator bits may take over some of the indicators that are
used on other indicator channels (for example some of the E-HICH
indicator bits would not be used for E-HICH purposes (e.g.
acknowledging uplink transmissions), but would be used for
transmission of FACH indicator bits instead).
[0080] Furthermore, the indicator bits may be either broadcast to
all UEs in a cell, or transmitted to a targeted group of one or
more UEs in a cell. For example, the targeted group of UEs may be a
group of UEs with a particular capability or may be a group of UEs
geographically located close to the Node B. An example method of
targeting a group of UEs would be to mask the indicator bits with a
scrambling code that is known to a group of UEs or to transmit the
indicator bits at a power level such that only that group of UEs is
able to receive the indicator bits reliably.
[0081] As previously mentioned, the FACH is a downlink transport
channel that is used to carry control information to a UE. The FACH
allows short messages to be sent from the network to the UE. These
short messages are typically control type messages that are used,
for example, to allocate physical resources to the UE, set up
dedicated physical channels, etc. In particular, the FACH provides
a service for a network to communicate with UEs, without having to
set up dedicated physical resources.
[0082] As previously mentioned, with respect to FIG. 4, the RNC 420
may instruct the Node B 410 those timeslot resources that are to be
reserved for the FACH, for example by way of a `NODE B SETUP`
message, along with the channelisation codes and transport formats
to be applied to the FACH. Furthermore, when the network needs to
send a FACH message to a UE, for example UE 430 of FIG. 4, the RNC
420 sends a message, for example a `SEND FACH` message, to the Node
B 410 comprising the content of the message, and the identity of
the UE 430, such as a UE-ID for which the message is intended. The
RNC 420 may also define other criteria such as the specific
timeslot resources to be used (from those reserved), specific
channelisation codes to be used, etc. Alternatively, the choice of
timeslot resources, channelisation codes, etc. may be left to the
Node B 410, and as such the Node B 410 schedules the transmission
of FACH messages within the, or each, FACH channel 520.
[0083] The BCH is a downlink transport channel that is used to
broadcast system and cell specific information. In particular, the
NODE B 410 may use the BCH 525 to transmit resource information
relating to common channels (where a common channel is a channel
that a plurality of UEs are meant to decode, in contrast to a
dedicated physical channel, which is meant to be decoded by a
specific UE). The resource information may comprise descriptions of
channelisation codes for common physical channels, timeslot
resource allocations, and formats for transport channels such as
coding and modulation.
[0084] For the illustrated embodiments, the INCH 521 further
comprises one or more indicator bits, at least one of which
comprises a FACH indicator bit 522. In this manner, the resource
information on BCH further comprises description of the at least
one indicator bit within the INCH 521.
[0085] The FACH indicator bit is used to indicate whether a FACH
channel to which it relates is `active`. Thus, for the embodiments
illustrated in FIG. 5, the FACH indicator bit 522 is used to
indicate whether the FACH is `active`.
[0086] When the NODE B 410 is required to send a FACH message, for
example having received a SEND FACH message from the RNC 420, the
NODE B 410 sets the FACH indicator bit 522, as illustrated in FIG.
5. The NODE B 410 also transmits the FACH message within the FACH
timeslot, along with the identity of the UE, for example the UE-ID,
for which the message is intended.
[0087] In this manner, a UE 430 attached to the NODE B 410, is able
to determine whether there is a FACH message by monitoring the INCH
521, and in particular by reading the FACH indicator bit 522. Upon
reading a set FACH indicator bit, the UE 430 determines that the
NODE B 430 is transmitting a FACH message, and using the resource
information being transmitted in the BCH 525, is able to decode the
FACH message. If the identity of the UE 430 matches the identity
transmitted within the FACH message, the UE 430 acts on the message
content.
[0088] Referring now to FIG. 6 there is illustrated the resource
allocation of FIG. 5, where no FACH message is required to be
transmitted. As the NODE B 410 has no FACH message to transmit, the
FACH indicator bit 522 in the INCH 521 is not set. In this manner,
a UE 420 attached to the NODE B 410, for example UE 430, is able to
determine that the NODE B 110 is not transmitting a FACH message,
by reading the FACH indicator bit 522, and accordingly the UE does
not attempt to decode HS-DSCH resource as FACH. This may allow the
UE to conserve battery power and avoids the UE incorrectly decoding
HS-DSCH as FACH, thus improving reliability of the FACH
transmission.
[0089] As will be appreciated by a skilled artisan, since the NODE
B 410 is not transmitting a FACH message, the timeslot allocated to
the FACH 520 is free. Therefore, in accordance with embodiments of
the invention, the NODE B 410 is arranged to reallocate the FACH
timeslot 520 for use by a channel other than the FACH, when no FACH
message is required to be transmitted.
[0090] For the illustrated embodiments, the FACH timeslot 520 is
reallocated for use by the HS-DSCH 505. The HS-DSCH 505 is a shared
channel, the content and physical resources of which are allocated
via the HS-SCCH 515, which is a downlink physical channel that
carries control information for the HS-DSCH 505. A skilled artisan
will appreciate that, although the HS-SCCH 515 is illustrated
herein as occupying an entire timeslot, the HS-SCCH 515 may be
multiplexed with other channels.
[0091] As previously mentioned, when the NODE B 410 is not
transmitting a FACH message, it reallocates the FACH timeslot 520
for use by another channel, which for the illustrated embodiments
is the HS-DSCH 505.
[0092] In this manner, when a FACH message is not being
transmitted, the resources available to the HS-DSCH 505 can be
expanded from, for the illustrated embodiments, seven timeslots to
eight, an increase of approximately 14%. Thus, embodiments of the
invention provide a more efficient use of physical resources, as
compared with traditional techniques for providing services, such
as that of FACH in traditional cellular communication systems.
[0093] Furthermore, unlike for the known solution for reusing the
FACH timeslot described above, as the HS-DSCH 505 and HS-SCCH 515
are not used for transmitting FACH messages, these two channels do
not each require a significant proportion (e.g. approximately 33%)
of the Node B transmit power when a FACH message is to be
transmitted. Rather, only the FACH, when a FACH message is being
transmitted, requires 33% of the Node B transmit power.
[0094] Thus, an embodiment of the invention may provide an
advantage of a more efficient use of physical resources, whilst
substantially avoiding an increase in power requirements.
[0095] For the embodiments illustrated in FIG. 5 and FIG. 6, the
FACH indicator bit 522 is illustrated as indicating 523 a state of
the FACH within the same frame. A skilled artisan will appreciate
that, for some UE implementations, this may not be feasible due to
the processing requirements this would place on the UE.
[0096] Referring now to FIG. 7, there is illustrated an example of
resource allocation in accordance with embodiments of the
invention. In the same way as for the embodiments illustrated in
FIG. 5 and FIG. 6, timeslots 710 within a frame are allocated to a
BCH 725, HS-DSCH 705, HS-SCCH 715, FACH 720, INCH 721, etc.
[0097] For the embodiments illustrated in FIG. 7, the INCH 721
comprises a plurality of indicator bits, one of which, for the
illustrated embodiments, is in the form of a FACH indicator bit
722, which indicates the state of the FACH 720 in a subsequent
frame of the physical channel. For the illustrated embodiments, the
FACH indicator bit 722 in frame `n` indicates 723 the state of the
FACH 720 within the next consecutive frame, frame `n+1`. Thus, in
FIG. 7, the FACH indicator bit 722 in frame `n` is set, and thereby
indicates that the FACH 720 is active in frame `n+1`. In this
manner, the processing requirements placed on a UE 430 are reduced,
since the UE 430 is provided more time in which to prepare to
decode the FACH 720 if the FACH 720 is active. As illustrated, the
HS-SCCH 715 may also relate 716 to the HS-DSCH 705 in the next
consecutive frame.
[0098] Referring now to FIG. 8, there is illustrated an example of
resource allocation in accordance with embodiments of the
invention. For the embodiments illustrated in FIGS. 5 to 7, a
single FACH indicator bit is used to indicate a state of a single
FACH, and the FACH is allocated an entire timeslot within the
physical channel. A skilled artisan will appreciate that a NODE B
may be arranged to provide more than one FACH, and that the
plurality of FACHs may be allocated to one or more timeslots.
[0099] For the embodiments illustrated in FIG. 8, four FACH
channels are allocated to a single timeslot, and the FACH indicator
bit 822 indicates 823 whether at least one of the FACH channels is
active. In this manner, if the NODE B is required to transmit one
or more FACH messages, the NODE B sets the FACH indicator bit 822,
and transmits the one or more FACH messages in one or more FACH
channels 820 within the allocated timeslot. In this manner, a UE is
able to determine whether a FACH message is to be transmitted by
reading the FACH indicator bit 822 in the INCH 821. If the FACH
indicator bit 822 is set, the UE then decodes the FACH timeslot and
reads each of the four FACH channels therein to determine whether
the one or more transmitted FACH messages are intended for
itself.
[0100] If the NODE B is not required to transmit a FACH message,
the NODE B sets the FACH indicator bit 822 to `inactive`, and
reallocates the FACH timeslot for use by another transport channel,
for example the HS-DSCH 805.
[0101] Referring now to FIG. 9, there is illustrated an example of
resource allocation in accordance with embodiments of the
invention. As in the embodiment illustrated in FIG. 8, four FACH
channels are allocated to a single timeslot. However, for the
embodiments illustrated in FIG. 9, the INCH 921 comprises a
plurality of FACH indicator bits 922. For the illustrated
embodiments, the INCH 921 comprises four FACH indicator bits 922,
each FACH indicator bit 922 relating to one of the FACH channels
920.
[0102] In this manner, when the NODE B receives one or more FACH
messages to be transmitted, the NODE B schedules transmission of
the one or more FACH messages in one or more of the FACH channels
920, and sets one or more of the FACH indicator bits 922, to
indicate those FACH channels 920 that are active.
[0103] Thus, FIG. 9 illustrates a case where the NODE B is required
to transmit two FACH messages. Accordingly, the NODE B has set two
of the FACH indicator bits 922, and transmits the FACH messages
within the two corresponding FACH channels 920. As will be
appreciated by a skilled artisan, for the embodiments illustrated
in FIG. 9, only two out of four of the FACH channels 920 within the
FACH timeslot are used. Accordingly, and in accordance with an
embodiment of the invention, the NODE B re-allocates the timeslot
resource for those FACH channels not required for transmitting FACH
messages, for use by another transport channel, such as the HS-DSCH
905. In this manner, even when the NODE B is required to transmit
FACH messages, free resource within the FACH allocated timeslot may
be reused for other channels.
[0104] In the embodiments shown in FIG. 9, where a timeslot is
partially used by FACH, a UE that is allocated HS-DSCH may
advantageously modify its resource allocation based on the status
of the FACH indicator bit. For example, if the UE is allocated all
eight timeslots and all sixteen codes on HS-DSCH 905, and the FACH
indicator bit is set, the UE may understand that in the FACH
timeslot 920 it is actually allocated a reduced number of HS-DSCH
codes. This is in contrast to the existing operation in 3GPP, where
the same number of codes has to be allocated to a UE in all of the
timeslots that it is allocated, due to signalling restrictions.
However, in accordance with embodiments of the invention, the UE is
signaled whether the FACH is active. Advantageously, the UE is able
to use this indication to modify the HS-DSCH resource allocation
(as the UE understands that if the FACH indicator bit was set, then
the UE cannot be allocated all of the resource in the FACH timeslot
as that resource is allocated elsewhere as FACH).
[0105] For the various embodiments illustrated and described
herein, a single timeslot has been allocated for FACH channels.
However, a skilled artisan will appreciate that more than one
timeslot may be allocated for FACH channels. Accordingly, and in
accordance with an embodiment of the invention, where more than one
timeslot is allocated for FACH channels, the one or more timeslots
may, individually or collectively, and as a whole or partly, be
re-allocated for use by other channels when not required for the
transmission of FACH messages.
[0106] Referring now to FIG. 10, there is illustrated a flow chart
1000 of a method for transmitting transport channels over a
physical channel of a cellular communication system in accordance
with embodiments of the invention.
[0107] The method starts at block 1010 and moves to block 1020,
where it is determined whether a FACH message is required to be
transmitted, for example whether a `SEND FACH` command has been
received from an RNC.
[0108] If it is determined that a FACH message is required to be
transmitted, the method moves on to block 1030, where the FACH
message(s) to be transmitted is/are scheduled for transmission in
one or more timeslots allocated to one or more FACH channels. The
method then moves on to block 1050.
[0109] Referring back to block 1020, if it is determined that no
FACH message is required to be transmitted, the method moves on to
block 1040, where the timeslot(s) allocated to the one or more FACH
channels are re-allocated for use by one or more channels other
than the one or more FACH channels. The method then moves on to
block 1050.
[0110] In block 1050, the FACH indicator bit is configured as
required for transmission in, for example a broadcast channel or
indicator channel, indicating whether the FACH is active, e.g. a
FACH message is to be transmitted, or not. That is to say, if a
FACH message is to be transmitted, the FACH indicator bit is set
(e.g. transmitted as a logic `1`), whereas if a FACH message is not
to be transmitted, the FACH indicator bit is not set (e.g.
transmitted as a logic `0` or alternatively the FACH indicator bit
is simply not sent at all (for example in a Discontinuous
Transmission (DTX) mode)). The method then moves on to block 1060,
where the transmission of the transport channels is initiated. The
method then returns to block 1020, as shown.
[0111] A skilled artisan will appreciate that only those blocks
pertinent to the invention have been illustrated and described in
order not to obscure the inventive concept.
[0112] Referring now to FIG. 11, there is illustrated a flowchart
1100 of a method for transmitting transport channels over a
physical channel of a cellular communication system, in accordance
with embodiments of the invention.
[0113] The method starts at block 1110 and moves to block 1120,
where it is determined whether a FACH message is required to be
transmitted. If it is determined that one or more FACH messages are
required to be transmitted, the method moves on to block 1130,
where the one or more FACH message(s) is/are scheduled for
transmission within the allocated timeslot(s).
[0114] The method then moves on to block 1140, where it is
determined whether resources allocated for FACH messages are free
for use by other channels. If it is determined that no FACH
resources are free in block 1140, the method moves on to block
1160. However, if it is determined that FACH resources are free,
the method moves on to block 1150.
[0115] Referring back to block 1120, if it is determined that no
FACH messages are required to be transmitted, the method moves on
to block 1150, where resources allocated for FACH messages that are
not required for the transmission of FACH messages are re-allocated
for use by other channels.
[0116] The method then moves to block 1160, where the, or each,
FACH indicator bit is configured as being required within a
broadcast channel or indicator channel, indicating whether the FACH
is active, e.g. a FACH message is to be transmitted, or not. The
method then moves on to block 1170, where the transmission of the
transport channels is initiated. The method then returns to block
1120.
[0117] A skilled artisan will appreciate that only those blocks
pertinent to the invention have been illustrated and described in
order not to obscure the inventive concept.
[0118] For the various embodiments hereinbefore described, the, or
each, indicator bit has been described as being provided within an
indicator channel. Alternatively the indicator bits may be sent on
the BCH or other channel. By way of example, the indicator bit(s)
may be sent within a Transport Format Combination Indicator (TFCI)
type field within the BCH, wherein the TFCI field is a field that
is separately encoded to data traffic to which it relates. As
another example, the indicator bits may be sent in the data portion
of the BCH or other channel.
[0119] In an embodiment of the invention, the indicator bit(s) may
be provided within a dedicated indicator channel. The indicator
bits may also be transmitted as repetition encoded bits, or
alternatively they may be more robustly encoded, such as jointly
convolutionally encoded.
[0120] Alternatively, indicator bits may be transmitted within an
indicator channel along with other indicator bits. For example
indicator bits from the PICH (Paging Indicator CHannel) or E-HICH
(E-DCH Hybrid ARQ Indicator CHannel) channels may be reassigned as
FACH indicator bits.
[0121] While the invention has been described in terms of
particular embodiments and illustrative figures, those of ordinary
skill in the art will recognize that the invention is not limited
to the embodiments or figures described. Although embodiments of
the present invention are described, in some instances, using UMTS
terminology, those skilled in the art will recognize that such
terms are also used in a generic sense herein, and that the present
invention is not limited to such systems.
[0122] Those skilled in the art will recognize that the operations
of the various embodiments may be implemented using hardware,
software, firmware, or combinations thereof, as appropriate. For
example, some processes can be carried out using processors or
other digital circuitry under the control of software, firmware, or
hard-wired logic. (The term `logic` herein refers to fixed
hardware, programmable logic and/or an appropriate combination
thereof, as would be recognized by one skilled in the art to carry
out the recited functions.) Software and firmware can be stored on
computer-readable media. Some other processes can be implemented
using analog circuitry, as is well known to one of ordinary skill
in the art. Additionally, memory or other storage, as well as
communication components, may be employed in embodiments of the
invention.
[0123] FIG. 12 illustrates a typical computing system 1200 that may
be employed to implement processing functionality in embodiments of
the invention. Computing systems of this type may be used in the
NodeB (in particular, the scheduler of the NodeB), core network
elements, such as the GGSN, and RNCs, for example. Those skilled in
the relevant art will also recognize how to implement the invention
using other computer systems or architectures. Computing system
1200 may represent, for example, a desktop, laptop or notebook
computer, hand-held computing device (PDA, cell phone, palmtop,
etc.), mainframe, server, client, or any other type of special or
general purpose computing device as may be desirable or appropriate
for a given application or environment. Computing system 1200 can
include one or more processors, such as a processor 1204. Processor
1204 can be implemented using a general or special purpose
processing engine such as, for example, a microprocessor,
microcontroller or other control logic. In this example, processor
1204 is connected to a bus 1202 or other communications medium.
[0124] Computing system 1200 can also include a main memory 1208,
such as random access memory (RAM) or other dynamic memory, for
storing information and instructions to be executed by processor
1204. Main memory 1208 also may be used for storing temporary
variables or other intermediate information during execution of
instructions to be executed by processor 1204. Computing system
1200 may likewise include a read only memory (ROM) or other static
storage device coupled to bus 1202 for storing static information
and instructions for processor 1204.
[0125] The computing system 1200 may also include information
storage system 1210, which may include, for example, a media drive
1212 and a removable storage interface 1220. The media drive 1212
may include a drive or other mechanism to support fixed or
removable storage media, such as a hard disk drive, a floppy disk
drive, a magnetic tape drive, an optical disk drive, a compact disc
(CD) or digital video disk (DVD) read or write drive (R or RW), or
other removable or fixed media drive. Storage media 1218 may
include, for example, a hard disk, floppy disk, magnetic tape,
optical disk, CD or DVD, or other fixed or removable medium that is
read by and written to by a media drive. As these examples
illustrate, the storage media 1218 may include a computer-readable
storage medium having stored therein particular computer software
or data.
[0126] In alternative embodiments, information storage system 1210
may include other similar components for allowing computer programs
or other instructions or data to be loaded into computing system
1200. Such components may include, for example, a removable storage
unit 1222 and an interface 1220, such as a program cartridge and
cartridge interface, a removable memory (for example, a flash
memory or other removable memory module) and memory slot, and other
removable storage units 1222 and interfaces 1220 that allow
software and data to be transferred from the removable storage unit
1222 to computing system 1200.
[0127] Computing system 1200 can also include a communications
interface 1224. Communications interface 1224 can be used to allow
software and data to be transferred between computing system 1200
and external devices. Examples of communications interface 1224 can
include a modem, a network interface (such as an Ethernet or other
NIC card), a communications port (such as for example, a universal
serial bus (USB) port), a PCMCIA slot and card, etc. Software and
data transferred via communications interface 1224 are in the form
of signals which can be electronic, electromagnetic, optical or
other signals capable of being received by communications interface
1224. These signals are provided to communications interface 1224
via a channel 1228. This channel 1228 may carry signals and may be
implemented using a wireless medium, wire or cable, fiber optics,
or other communications medium. Some examples of a channel include
a phone line, a cellular phone link, an RF link, a network
interface, a local or wide area network, and other communications
channels.
[0128] In this document, the terms `computer program product`
`computer-readable medium` and the like may be used generally to
refer to media such as, for example, memory 1208, storage device
1218, or storage unit 1222. These and other forms of
computer-readable media may store one or more instructions for use
by processor 1204, to cause the processor to perform specified
operations. Such instructions, generally referred to as `computer
program code` (which may be grouped in the form of computer
programs or other groupings), when executed, enable the computing
system 1200 to perform functions of embodiments of the present
invention. Note that the code may directly cause the processor to
perform specified operations, be compiled to do so, and/or be
combined with other software, hardware, and/or firmware elements
(e.g., libraries for performing standard functions) to do so.
[0129] In an embodiment where the elements are implemented using
software, the software may be stored in a computer-readable medium
and loaded into computing system 1200 using, for example, removable
storage drive 1212 or communications interface 1224. The control
logic (in this example, software instructions or computer program
code), when executed by the processor 1204, causes the processor
1204 to perform the functions of the invention as described
herein.
[0130] It will be appreciated that, for clarity purposes, the above
description has described embodiments of the invention with
reference to different functional units and processors. However, it
will be apparent that any suitable distribution of functionality
between different functional units, processors or domains may be
used without detracting from the invention. For example,
functionality illustrated to be performed by separate processors or
controllers may be performed by the same processor or controller.
Hence, references to specific functional units are only to be seen
as references to suitable means for providing the described
functionality, rather than indicative of a strict logical or
physical structure or organization.
[0131] Although the invention has been described in connection with
embodiments, it is not intended to be limited to the specific form
set forth herein. Rather, the scope of the present invention is
limited only by the claims Additionally, although a feature may
appear to be described in connection with particular embodiments,
one skilled in the art would recognize that various features of the
described embodiments may be combined in accordance with the
invention. In the claims, the term `comprising` does not exclude
the presence of other elements or steps.
[0132] Furthermore, although individually listed, a plurality of
means, elements or method steps may be implemented by, for example,
a single unit or processor. Additionally, although individual
features may be included in different claims, these may possibly be
advantageously combined, and the inclusion in different claims does
not imply that a combination of features is not feasible and/or
advantageous. Also, the inclusion of a feature in one category of
claims does not imply a limitation to this category, but rather the
feature may be equally applicable to other claim categories, as
appropriate.
[0133] Furthermore, the order of features in the claims does not
imply any specific order in which the features must be performed
and in particular the order of individual steps in a method claim
does not imply that the steps must be performed in this order.
Rather, the steps may be performed in any suitable order. In
addition, singular references do not exclude a plurality. Thus,
references to `a`, `an`, `first`, `second`, etc. do not preclude a
plurality.
[0134] It will be understood that the method and apparatus for
transmitting transport channels over a physical channel of a
cellular communication system described above provides, by way of
example only, at least the advantages of a more efficient use of
physical resources, whilst substantially avoiding an increase in
power requirements.
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