US008005481B2
`
`(12) United States Patent
`Bergstrom et al.
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 8,005,481 B2
`Aug. 23, 2011
`
`(54) UPLINK SCHEDULING IN A MOBILE
`TELECOMMUNICATION NETWORK
`
`(56)
`
`References Cited
`
`(75)
`
`Inventors: Joakim Bergstrom, Stockholm (SE);
`Johan Torsner, Masaby (F1)
`.
`(73) Assigneez Telefonaktiebolaget LM Ericsson
`(publ), Stockholm (SE)
`
`U.S. PATENT DOCUMENTS
`-
`?;°1—‘;‘;iI§;ff 31'
`33333;
`2:33:32‘? 31
`................ .. 370/329
`7,145,889 B1 * 12/2006 Zhang et al.
`.... .. 370/347
`7,463,616 B1 * 12/2008 Earnshaw et al.
`
`................ .. 370/395.4
`7,551,625 B2 *
`6/2009 Ahn et al.
`2004/0258026 A1
`12/2004 Lau
`
`( * ) Notice:
`
`Subject to any disclaimer, the term of this
`patent IS extended 01' adjusted under 35
`U'S'C' 15403) by 0 days‘
`
`3/2005 Love et 31'
`2005/0047360 A1
`FOREIGN PATENT DOCUMENTS
`1 096 696
`5/2001
`
`EP
`
`(21) Appl. NO.Z
`
`11/921,039
`
`(22) PCT Filed;
`
`May 26; 2005
`
`(86) PCT No;
`
`PCT/SE2005/000786
`
`OTHER PUBLICATIONS
`
`International Search Report for PCT/SE2005/000786 mailed Jan. 25,
`2006.
`
`Written Opinion, Jan. 25, 2006 in corresponding PCT Application
`No. PCT/SE2005/00786.
`
`§ 371 (c>(1>,
`(2), (4) Date:
`
`Dec. 29, 2008
`
`,
`,
`* clted by examlner
`
`(87) PCT P1111 N01 W02006/126920
`Date. No“ 30’
`
`Primary Examiner — Pierre-Louis Desir
`AlZ0}"l’l€y, Agent, 0}’ Firm * NIXOII & Vanderhye
`
`(65)
`
`Prior Publication Data
`
`(57)
`
`ABSTRACT
`
`US 2009/0143071 A1
`
`Jun. 4; 2009
`
`(51)
`
`Int. Cl.
`(2009.01)
`H04 W 4/00
`(52) US, Cl,
`....... ., 455/450; 370/329; 370/330; 370/347
`(58) Field of Classification Search ................ .. 370/347,
`370/330, 329; 455/450
`See application file for complete search history.
`
`A node B comprises a downlink data scheduler and an uplink
`data scheduler. Information associated with a downlink data
`
`transfer is transferred from the downlink data scheduler to
`said uplink data scheduler. The uplink data scheduler sched-
`ules an uplink data transfer as a result of the transmission of
`the downhnk data transfer.
`
`19 Claims, 1 Drawing Sheet
`
`ERICSSON EXHIBIT 1009
`
`

`
`U.S. Patent
`
`Aug. 23, 2011
`
`US 8,005,481 B2
`
`Downlink Scheduler
`
`Uplink Scheduler
`
`204
`
`Fig. 2
`
`

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`US 8,005,481 B2
`
`1
`UPLINK SCHEDULING IN A MOBILE
`TELECOMMUNICATION NETWORK
`
`This application is the U.S. national phase of International
`Application No. PCT/SE2005/000786 filed 26 May 2005
`which designated the U.S., the entire contents of each of
`which are hereby incorporated by reference.
`
`TECHNICAL FIELD
`
`The technology described herein relates to a method and
`arrangements in a mobile telecommunication network. In
`particular, the technology described herein relates to a Node
`B that facilitates an improved performance for implemented
`applications in said network.
`
`BACKGROUND
`
`The technology described herein relates to methods and
`arrangements in a Node B in a UMTS terrestrial radio access
`network (UTRAN). The UTRAN is illustrated in FIG. 1 and
`comprises at least one Radio Network System 100 connected
`to the Core Network (CN) 200. The CN is connectable to
`other networks such as the Internet, other mobile networks
`e.g. GSM systems and fixed telephony networks. The RNS
`100 comprises at least one Radio Network Controller 110.
`Furthermore, the respective RNC 110 controls a plurality of
`Node-Bs 120,130 that are connected to the RNC by means of
`the Iub interface 140. Each Node B covers one or more cells
`
`and is arranged to serve the User Equipment CUE) 300 within
`said cell. Finally, the UE 300, also referred to as mobile
`terminal,
`is connected to one or more Node Bs over the
`Wideband Code Division Multiple Access (WCDMA) based
`radio interface 150.
`In 3GPP Release 6, the WCDMA standard is extended with
`the Enhanced Uplink concept—the Enhanced Dedicated
`Transport Charmel, E-DCH. A further description can be
`found in 3GPP TS 25.309 “FDD Enhanced Uplink; Overall
`description”. This concept introduces considerably higher
`peak data-rates in the WCDMA uplink. Features introduced
`with E-DCH include fast scheduling and fast hybrid ARQ
`with soft combining, both of these features are located in the
`Node B.
`
`HARQ is a more advanced form of an ARQ retransmission
`scheme. In conventional ARQ schemes the receiver checks if
`a packet is received correctly. Ifit is not received correctly, the
`erroneous packet
`is discarded and a retransmission is
`requested. With HARQ the erroneous packet is not discarded.
`Instead the packet is kept and combined with a result of the
`retransmission. That implies that even if both the first trans-
`mission and the retransmission are erroneous, they may be
`combined to a correct packet. This means that fewer retrans-
`missions are required.
`Fast scheduling means that the Node B can indicate to each
`UE the rate the UE is allowed to transmit with. This can be
`
`done every TTI, i.e. fast. Thus, the network is able to control
`the interference in the system very well.
`In HS-DSCH (High Speed Downlink Shared Channel),
`that is described in 3GPP TS 25.308 “UTRA High Speed
`DownLink Packet Access (HSDPA); Overall description;
`Stage 2, the scheduling is also located in the Node B. In
`HS-DSCH the scheduling is rather straight forward since the
`Node B scheduler has full knowledge ofthe data that needs to
`be transmitted in downlink. Based on the amount of data
`
`available for different UEs, the priority of the data and the
`radio channel quality which is indicated by the UE through
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`the
`the Charmel Quality Indicator (CQI) measurements,
`scheduler determines which data that should be transmitted to
`each UE.
`On E-DCH the situation is different. The Node B scheduler
`has no direct information about the data that is to be trans-
`
`mitted from the UEs. Thus the UEs are required to indicate the
`amount of data available, the priority of the data, the trans-
`mitter power available etc. to the Node B through scheduling
`requests. When the Node B has received the scheduling
`request from the UE and has decided to schedule the UE
`based on the received scheduling requests, it transmits an
`absolute grant (AG), also denoted scheduling grant indicator
`herein, to the UE, indicating the amount of data or actually
`with which power the UE is allowed to transmit.
`Before an uplink data burst can be transmitted, the UE must
`first transmit a scheduling request to the Node B, to inform the
`Node B that data is available for transmission. After a recep-
`tion of the AG from the Node B the data burst can be trans-
`
`mitted. Thus, this procedure causes a delay in the beginning
`of a data transfer and potentially for each burst that is trans-
`mitted uplink, depending on how long the absolute grant is
`valid.
`
`The delay caused by scheduling can partly be avoided by
`either using non-scheduled transmissions or issuing perma-
`nent absolute grants to all UEs. The non scheduled transmis-
`sions imply that the network configures a certain rate statis-
`tically that the UE is allowed to use instantaneously without
`sending a scheduling request. The drawback ofthis solution is
`that the configured rate must be rather high in order to support
`all possible trafiic scenarios and may therefore require a large
`hardware allocation in the network and cause high interfer-
`ence. In the other solution, to permanently issue an absolute
`grant, it is possible to quickly change the value ofthe grant or
`remove the grant if the load of the network increases. How-
`ever, this other solution has the drawback that the network
`does not know which users that really need the permanent
`grant and the risk is therefore that the performance of the
`uplink data transmission is impacted. Accordingly, it would
`be desired to avoid said delay and at the same time avoid the
`drawbacks mentioned above.
`
`Many applications mainly involve dow11link data transfer,
`e.g. file download, video streaming, and web surfing. The
`downlink scheduling only imposes a small delay unless the
`system load is very high. However, since most applications
`involve sending feedback messages in the uplink, such as
`Transfer Control Protocol (TCP) acknowledgements (ACK)
`and Radio Link Control (RLC) ACKs, the delay in uplink
`scheduling will affect the performance significantly of the
`downlink data trafiic.
`
`SUMMARY
`
`Thus, the problem is to improve application performance.
`The Node B makes it possible to improve application per-
`formance. The Node B comprises a downlink data scheduler
`and an uplink data scheduler, and means for transferring
`information associated with a downlink data transfer from
`
`said downlink data scheduler to said uplink data scheduler.
`Moreover, the uplink data scheduler comprises means for
`scheduling an uplink data transfer as a result of the transmis-
`sion of said downlink data transfer.
`
`The method, makes it possible to improve application per-
`formance. The method comprises the steps of: transferring
`information associated with a downlink data transfer from
`
`said downlink data scheduler to said uplink data scheduler,
`and scheduling an uplink data transfer as a result of the
`transmission of said downlink data transfer.
`
`

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`US 8,005,481 B2
`
`3
`the uplink transfer is a
`According to an embodiment,
`response of the downlink data transfer.
`According to a further embodiment, the means for sched-
`uling an uplink data transfer comprises means for transmit-
`ting a scheduling grant indicator indicating when and/or how
`the UE is allowed to transmit uplink data. I.e. the scheduling
`grant indicator may comprise infonnation about allowed
`transmit power for the UE and that the UE is allowed to
`transmit until further notice.
`
`An advantage with the technology described herein is that
`it allows uplink response messages such as TCP ACKs, RLC
`ACKs and RRC response messages to be transmitted without
`scheduling delay, i.e. the scheduling request phase can be
`omitted. This will improve the performance for a large range
`of applications.
`
`DETAILED TECHNICAL DESCRIPTION OF THE
`INVENTION
`
`As stated above it would be desirable to be able to start an
`
`uplink transmission without performing a preceding sched-
`uling request, in particular when the uplink transmission is a
`response of a previously transmitted downlink transmission.
`That is achieved by the Node B shown comprising a down-
`link data scheduler 202, an uplink data scheduler and means
`for transferring information associated with a downlink data
`from said downlink data scheduler to said uplink data sched-
`uler. The uplink data scheduler comprises means for sched-
`uling an uplink data transfer, as a result ofthe transmission of
`said downlink data transfer
`The scheduler for the downlink trafiic is located in the same
`
`Node B as the scheduler for the uplink traffic. That is the case
`when the HS-DSCH serving Node B is the same as the
`E-DCH serving Node B. For HS-DSCH and E-DCH, the
`serving Node B is that Node B that is adapted to schedule the
`UE. For HS-DSCH, the serving Node B also transmits data to
`the UE.
`When the HS-DSCH scheduler schedules a data burst in
`
`the downlink to a UE, it informs the E-DCH uplink scheduler
`that the downlink data has been scheduled, or will be sched-
`uled within a certain time period. When the E-DCH scheduler
`receives this indication, it allocates a scheduling grant, also
`denoted absolute grant, for the UE for uplink resources. It is
`then possible for the UE to send response messages such as
`TCP ACKs, RLC ACKs, RRC response messages on the
`scheduled uplink resources. The uplink response messages
`can be transmitted without a prior scheduling request phase,
`which results in a decreased delay.
`According to a preferred embodiment, the uplink transfer
`is a response of the downlink data transfer, i.e. the response
`may be a response message such as TCP ACKs, RLC ACKs
`and RRC response messages.
`For scheduling an uplink data transfer, a scheduling grant
`indicator is transmitted, also denoted absolute grant indicator,
`on a downlink charmel adapted to schedule the uplink data
`transfer. The scheduling grant indicator indicates when and/
`or how the UE is allowed to transmit uplink data. The sched-
`uling grant
`indicator may comprise information about
`allowed transmit power for the UE and that the UE is allowed
`to transmit until further notice. The scheduling grant indicator
`may also indicate that the UE is allowed to transmit during a
`specific time interval.
`The scheduling grant indicator may be transmitted simul-
`taneously as the transmission of said downlink data transfer.
`According to embodiments, the scheduling grant indicator
`for the uplink scheduling is sent on the existing scheduling
`channel adapted to schedule the uplink, the enhanced Abso-
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`lute Grant Channel (E-AGCH). However, the absolute grant
`indicator for the uplink may also be included in a downlink
`message transmitted together with the downlink data trans-
`mission, i.e. on the same charmel e.g. on the HS-DSCH.
`The E-DCH scheduler may allocate a fixed preconfigured
`uplink resource to a U3 that already is scheduled in the
`downlink. Ifthe UE needs to transmit uplink information, e.g.
`TCP ACK, RLC ACK, or a RRC response message,
`in
`response to the receivec downlink data, the absolute grant
`indicator allocates uplink resources for the uplink data within
`a rather short time period after the downlink data was received
`e.g. within 200 ms. After that time period has elapsed or after
`the first transmission in uplink, the scheduler can reduce the
`absolute grant to zero to free uplink resources for other UEs.
`According to a further embodiment, the ab solute grant
`allocated to the UE in uplink may depend on the amount of
`data, or the data rate used, in downlink. In a preferred embodi-
`ment the absolute grant allocated to the UE in uplink may
`depend on the amount of data, or the data rate used, in down-
`link in addition to the time aspect described above. As an
`example the amount of allocated uplink resources indicated
`by the absolute grant indicator may be proportional to the
`amount of downlink data, i.e. the amount ofuplink data that is
`allowed to be transmitted is proportional to the amount of
`transmitted downlink data. Preferably, a rule for TCP appli-
`cations is that roughly l-3% of the downlink data rate is
`needed for TCP ACKs in uplink if no header compression is
`used.
`
`It should be noted that for applications using TCP the first
`request for data is transmitted in uplink and that request will
`not benefit from this invention. However, once the TCP data
`transfer has started, the data is transmitted in bursts separated
`by some time (in the slow start phase). Each of these bursts
`will benefit from the invention and the total time to e.g.
`download a file will thus be decreased.
`
`In the drawings and specification, there have been dis-
`closed typical preferred embodiments and, although specific
`terms are employed, they are used in a generic and descriptive
`sense only and not for purposes of limitation, the scope ofthe
`invention being set forth in the following claims.
`The invention claimed is:
`1. A node B base station comprising:
`a downlink data scheduler;
`an uplink data scheduler;
`means for transferring information associated with a
`downlink data transfer of a data packet received from a
`data packet network intended for a user equipment (UE)
`from said downlink data scheduler to said uplink data
`scheduler,
`wherein the uplink data scheduler is configured to schedule
`an initial uplink transfer of uplink data to be transmitted
`by the user equipment (UE) for a first time over a radio
`interface using said information as a result of transmit-
`ting said downlink data over the radio interface,
`wherein the uplink data scheduler is further configured to
`schedule the initial uplink transfer of the uplink data by
`the user equipment (UE) for the first time over the radio
`interface independently and regardless of whether a
`request to transmit the data by the user equipment (UE)
`has been received by the node B base station.
`2. The node B base station according to claim 1, wherein
`the uplink transfer of the data is in response to the downlink
`data transfer.
`
`3. The node B base station according to claim 1, further
`comprising means for transmitting a scheduling grant indica-
`tor indicating when and/or how the UE is allowed to transmit
`the uplink data over the radio interface to the node B.
`
`

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`US 8,005,481 B2
`
`5
`4. The node B base station according to claim 1, further
`comprising means for transmitting a scheduling grant indica-
`tor simultaneously with the transmission of said downlink
`data.
`
`5. The node B base station according to claim 1, further
`comprising means for transmitting a scheduling grant indica-
`tor included in a downlink message transmitted on a same
`channel as the downlink data transmission.
`
`6. The node B base station according to claim 1, further
`comprising means for transmitting a scheduling grant indica-
`tor on a downlink channel adapted to schedule the initial
`uplink transfer of the uplink data.
`7. The node B base station according to claim 6, wherein
`the downlink channel adapted to schedule the uplink data
`transfer is an enhanced Absolute Grant Channel.
`
`8. The node B base station according to claim 1, wherein
`the uplink data scheduler is further configured to schedule the
`initial uplink transfer of the uplink data within a predefined
`time period after the downlink data is received.
`9. The node B base station according to claim 1, further
`comprising means for allocating an amount of uplink
`resources in relation to an amount of transmitted downlink
`data.
`
`10. The node B base station according to claim 1, wherein
`the node B is implemented in a Universal Mobile Telephone
`System.
`11. A method in a Node B base station comprising a down-
`link data schcdulcr and an uplink data schcdulcr thc method
`comprising the steps of:
`transferring information associated with a downlink data
`transfer of a data packet received from a data packet
`network intended for a user equipment CUE) from said
`downlink data scheduler to said uplink data scheduler,
`and
`scheduling an initial uplink transfer of uplink data to be
`transmitted by the user equipment CUE) for a first time
`over a radio interface using said information as a result
`of transmitting said downlink data over the radio inter-
`face including scheduling the initial uplink transfer of
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`the uplink data by the user equipment CUE) for the first
`time over the radio interface independently and regard-
`less of whether a request to transmit the data by the user
`equipment CUE) has been received by the node B base
`station.
`
`12. The method according to claim 11, wherein the uplink
`transfer is in response to the downlink data transfer.
`13. The method according to claim 11, wherein the step of
`schedu ing the uplink transfer comprises the further step of
`transm'tting a scheduling grant indicator indicating when
`and/or 10W the UE is allowed to initially transmit the uplink
`data over the radio interface to the node B base station.
`
`14. The method according to claim 13, wherein the step of
`schedu ing the uplink transfer comprises the step oftransmit-
`ting a scheduling grant indicator simultaneously as the trans-
`mission of said downlink data.
`
`15. The method according to claim 14, wherein the step of
`schedu ing the uplink transfer comprises the step oftransmit-
`ting a scheduling grant indicator included in a downlink mes-
`sage transmitted on a same charmel as the downlink data
`transm'ssion.
`
`16. The method according to claim 11, wherein the step of
`schedu ing the uplink transfer comprises the step oftransmit-
`ting a scheduling grant indicator on a downlink channel
`adapted to schedule the initial uplink transfer of the uplink
`data.
`
`17. The method according to claim 16, wherein the down-
`link charmel adapted to schedule the initial uplink transfer of
`the uplink data is an enhanced Absolute Grant Channel.
`18. The method according to claim 11, wherein the step of
`scheduling the initial uplink transfer of the uplink data com-
`prises the step of scheduling the initial uplink transfer of the
`uplink data within a predefined time period after the downlink
`data is received.
`19. The method according to claim 11, wherein the step of
`scheduling the initial uplink transfer of the uplink data com-
`prises the step of allocating an amount of uplink resources in
`relation to an amount of transmitted downlink data.
`*
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