WO2008010750A1

WO2008010750A1 - Enhanced up-link

Info

Publication number: WO2008010750A1
Application number: PCT/SE2006/050260
Authority: WO
Inventors: Mathias Cramby; Erik Dahlman
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2006-07-17
Filing date: 2006-07-17
Publication date: 2008-01-24

Abstract

These objects among others are, according to a one aspect of the present invention, attained by a method in a radio communications network comprising a radio base station (RBS) for radio communication over a radio interface with a User Equipment (UE) using at least a first communication channel for transmitting Packet Data Units (PDU) between the radio base station and the UE. The method comprises the steps of : - providing a first bit in the PDU for use by the UE for indicating if the UE needs additional resources, and - providing at least a second bit in the PDU for use by the user equipment for indicating a priority.

Description

Enhanced Up-link TECHNICAL FIELD toooi] The present invention relates in general to mobile communications and more specifically to up-link communication in a radio communications network.

BACKGROUND

[ooo2] In radio communications networks, such as GSM, WCDMA etc. Protocol Data Units (PDU) are used as elements for peer-to-peer communication, such as between a User Equipment (UE) and a Node B, or Radio Base Station (RBS) .

[0003] A Medium Access Control (MAC) PDU is a bit string, with a length not necessarily a multiple of 8 bits. Depending on the provided service, MAC Service Data Units (SDU) are bit strings with any non-null length, or bit strings with an integer number of octets in length. An SDU is included into a MAC PDU from first bit onward.

[ooo4] In the UE for the uplink, all MAC PDUs delivered to the physical layer within one Transmission Time Interval (TTI) are defined as Transport Block Set (TBS) . It consists of one or several Transport Blocks, each containing one MAC PDU. The Transport Blocks are transmitted in the order as delivered from Radio Link Control (RLC) . When multiplexing of RLC PDUs from different logical channels is performed on MAC, the order of all Transport Blocks originating from the same logical channel are the same as the order of the sequence delivered from RLC. The order of the different logical channels in a TBS is set by the MAC protocol

[ooo5] In WCDMA Enhanced Uplink, the UE has the possibility to use something called happy bit for sending control information to their serving Enhanced Dedicated transport

Channel (E-DCH) Node-B. The happy bit is a single bit field that is passed from MAC to the physical layer for inclusion on the Enhanced Dedicated Physical Control Channel (E- DPCCH). This field takes two values, "Not Happy" and "Happy" indicating respectively whether the UE could use more resources or not.

[0006] The bit is set to "unhappy" by UE to indicate to the network that it has more data to transmit compared to what the UE has been granted.

[ooo7] The Happy Bit is included on the E-DPCCH for every E- DCH transmission. Radio Resource Control (RRC) configures MAC with the duration Happy_Bit_Delay_Condition, over which to evaluate the current grant relative to the Total E-DCH Buffer Status (TEBS) after application of the E-TFC selection procedure.

[ooo8] In WCDMA, for every E-DCH transmission, the Happy Bit shall be set to "unhappy" if the three following criteria are met:

[ooo9] 1) UE is transmitting as much scheduled data as allowed by the current Serving_Grant in E-TFC selection; and

[ooio] 2) UE has enough power available to transmit at higher data rate; and

[ooii] 3) Based on the same power offset as the one selected in E-TFC selection to transmit data in the same TTI as the Happy Bit, TEBS would require more than Happy_Bit_Delay_Condition ms to be transmitted with the current Serving_Grant x the ratio of active processes to the total number of processes.

[ooi2] The first criteria is always true for a deactivated process and the ratio of the third criteria is always 1 for 10ms TTI. [ooi3] Otherwise, the Happy Bit shall be set to "happy". Thus, the Happy bit is solely used for informing the network about the UE might be able to utilize more resources if allocated by the network.

tool*] In WCDMA Enhanced Uplink control signaling are handled by non-scheduled transmissions, which means the UE can transmit control signaling without being scheduled by the network. In WCDMA specific, non-scheduled, control channels are allocated to handle control signalling between the UE and the Node-B. Since, in WCDMA, it is power that is the physical resource the UE is sharing, it is possible to allocate a small amount of the power for control signalling without wasting resources.

tools] However, in a radio communications network, based on other access techniques, such as Orthogonal Frequency Division Multiplexing (OFDM) , where the physical resources are divided in time and frequency, a problem occurs when a UE has control signaling with high priority to transmit to the network.

[ooi6] In such a system it would be a waste of radio resources to allocate a specific time slot and frequency to each UE for control signaling, which then could not be used for User Plane traffic.

[ooi7] The UE may have been granted resources for user plane radio bearer which in principle could be used for control signaling, but user plane radio bearer typically has lower priority than the control signaling and therefore the signaling may be delayed if it is scheduled according to the user plane radio bearer. SUMMARY

[0018] One object according to an embodiment of the invention is to provide a network, node, method and user equipment in a radio communications network at least alleviating the above problems .

[ooi9] These objects, among others are, according to a one aspect of the present invention, attained by a method in a radio communications network comprising a radio base station (RBS) for radio communication over a radio interface with a User Equipment (UE) using at least a first communication channel for transmitting Packet Data Units (PDU) between the radio base station and the UE. The method comprises the steps of: - providing a first bit in the PDU for use by the UE for indicating if the UE needs additional resources, and - providing at least a second bit in the PDU for use by the user equipment for indicating a priority.

[0020] These objects among others are, according to another aspect of the present invention, attained by a method in a RBS for communication with a UE in a radio communications network over a radio interface using at least a first communications channel for transmitting PDU :s between the UE and the RBS .

[oo2i] The method comprises the steps of: - receiving a PDU from the user equipment, - evaluating a first bit in the received PDU indicating the data transmission requirements for the UE, - assigning resources to the UE, if available, and in dependence of the evaluation of the first bit, evaluating at least a second bit in the received PDU, and - assigning additional, or specific resources in dependence of the evaluation of the second bit.

[0022] These objects among others are, according to another aspect of the present invention, attained by a method in a UE for communication with a RBS in a radio communications network over a radio interface using at least a first communications channel for transmitting PDU :s between the UE and the RBS.

[0023] The method comprises the steps of: - evaluating the current data transmission requirements in the UE, - setting a first bit in the PDU in dependence of the evaluation of the current data transmission requirements, and - setting at least a second bit in the PDU indicating a priority of a data transmission requirement.

[0024] According to one embodiment of the present invention the current data transmission requirement is the current data transmission load.

[0025] According to one embodiment of the present invention the second bit indicates that the UE has control signalling to transmit.

[0026] According to one embodiment of the present invention the second bit indicates that the UE has prioritized user data to transmit.

[0027] According to one embodiment of the present invention the specific resources are control signalling resources.

[0028] According to one embodiment of the present invention further bits are provided in the PDU for indicating various levels of priority and wherein the highest level of priority is dedicated for control signalling.

[0029] These objects among others are, according to another aspect of the present invention, attained by a radio base station comprising means for performing any of the methods above . [0030] These objects among others are, according to another aspect of the present invention, attained by a user equipment comprising means for performing any of the methods above .

[oo3i] Further characteristics of the invention and advantages thereof will be evident from the following detailed description of embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention will become more fully understood from the detailed description of embodiments of the present invention given herein below and the accompanying Figs . 1 to 4, which are given by way of illustration only, and thus are not limitative of the present invention.

[0033] Figure 1 is a schematic block diagram according to one embodiment of the present invention.

[0034] Figure 2 is a schematic flow diagram according to one variant of the present embodiment for a method in a communications network.

[0035] Figure 3 is a schematic flow diagram according to another variant of the present invention for a method in a user equipment.

[0036] Figure 4 is a schematic flow diagram according to another variant of the present invention for a method in a radio base station, such as a Node B.

DETAILED DESCRIPTION

[0037] In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular techniques and applications in order to provide a thorough understanding of the present invention. However, it will be apparent to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known methods and apparatuses are omitted so as not to obscure the description of the present invention with unnecessary details .

[0038] Figure 1 is a schematic block diagram according to one variant of the present invention disclosing a user equipment 101 being in radio communication with a Node B 102 as is indicated with the flash arrow 103. The user equipment (UE) 101 is sending data stored in a buffer 104 in the user equipment 101 using Packet Data Units (PDU) 105, whereof one is shown for illustrative purposes. The Packet Data Units 105 are received in the Node B 102, the PDU is treated and the data is further communicated to other network nodes (not shown) in a conventional matter.

[0039] The transmission rate allocated to the user equipment 101 is controlled by the network. It could be controlled by the Node B 102 or by another node in the network, such as another Node B (not shown) , a Radio Network Controller (RNC) (not shown) or another control node.

[0040] When the user equipment 101 sends a PDU, the UE 101 examines the amount of data stored in the buffer 104 and evaluates other characteristics, such as current allocated transmission rate etc. to determine if the UE 101 would need additional resources, for instance to increase the transmission rate. If so determined, the UE 101 sets a first bit 106 in the PDU 105.

[oo4i] This first bit 106 is analysed at the Node B 102, and if resources are available, the allocation of resources to the UE 101 is increased.

[0042] Further more, the UE 101 also evaluates whether any control signalling need transmission to the Node B 102. If the UE 101 has control signalling to send and no control signal channels, i.e. no control plane radio bearers, are currently set up, the UE 101 also sets a second bit 107.

[oo43] The second bit 107 is also evaluated at the Node B 102, and if set, the appropriate signalling radio bearers are allocated to receive signalling from the UE 101.

[0044] According to one variant of the present invention the second bit 107 merely indicates that the UE needs to transmit prioritized data over the user plane.

[0045] If both prioritized data over the user plane, as well as control signalling over the control plane, needs to be handled a third bit may be used in the PDU 105.

[0046] Figure 2 is a schematic flow diagram according to one aspect of the present invention of a method in the radio access network illustrated in figure 1. In a first step 201 a first bit 106 is provided in a PDU 105 for indicating the need of additional resources .

[0047] In a second step 202 at least a second bit 107 is provided in the PDU 105 for indicating a priority. This could for instance indicate that a UE 101 has user data with higher priority to send, or that the UE 101 needs to transmit control signaling and requests that a control signaling radio bearer is set up.

[0048] Figure 3 is a schematic flow diagram according to one embodiment of the invention of a method in a UE 101. In a first step 301 the current data transmission requirements for the UE 101 are evaluated. These requirements may indicate that the UE 101 would prefer increased transmission rate, that the UE 101 has prioritized user data to transmit, that the UE 101 has control signaling to transmit etc.

[0049] In a second step the UE 101 sets a first bit 106 in a PDU 105, to be transmitted to the Node B, in dependence of the evaluation, and in a third step the UE 101 sets a second bit in dependence of the priority of a data transmission.

[0050] According to one variant of the present invention, the meaning of the provided bits is according to the following table:

[oo5i] According to another variant of the present invention, the meaning of the provided bits is according to the following table:

[0052] Figure 4 is a schematic flow diagram according to one variant of the present invention of a method in a Node B. In a step 402 a PDU 105 is received from a UE 101 and a first bit 106 is evaluated in a second step 107. Based on this evaluation resources are allocated in a step 403.

[0053] In a step 404 a second bit 107 is evaluated and additional resources or specific resources are allocated to the UE 101 in a step 405. Obviously, according to a variant of the present embodiment step 404 may be performed before step 403 and step 404 and step 405 may be performed simultaneousIy .

[0054] It will be obvious that the invention may be varied in a plurality of ways. Such variations are not to be regarded as a departure from the scope of the invention. All such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the appended claims.

Claims

1. A method in a radio communications network comprising a radio base station for radio communication over a radio interface with a User Equipment using at least a first communication channel for transmitting Packet Data Units between the radio base station and the User Equipment, comprising the steps of:

- providing a first bit in the Packet Data Unit for use by the user equipment for indicating if the User Equipment needs additional resources, characterised in the further step of:

- providing at least a second bit in the Packet Data Unit for use by the user equipment for indicating a priority.

2. A method in a radio base station for communication with a user equipment in a radio communications network over a radio interface using at least a first communications channel for transmitting Packet Data Units between the user equipment and the radio base station, comprising the steps of: - receiving a Packet Data Unit from the user equipment,

- evaluating a first bit of the received Packet Data Unit indicating the data transmission requirements for the user equipment,

- assigning resources to the user equipment, if available, and in dependence of the evaluation of the first bit, characterised by the step of:

- evaluating at least a second bit in the received Packet Data Unit, and - assigning additional, or specific resources in dependence of the evaluation of the second bit.

3. The method according to claim 2, wherein

- the current data transmission requirement is the current data transmission load.

4. The method according to claim 2 , wherein - the second bit indicates that the user equipment has control signalling to transmit.

5. The method according to claim 2 , wherein

- the second bit indicates that the user equipment has prioritized user data to transmit.

6. The method according to claim 2, wherein

- the specific resources are control signalling resources .

7. A method in a user equipment for communication with a radio base station in a radio communications network over a radio interface using at least a first communications channel for transmitting Packet Data Units between the user equipment and the radio base station, comprising the steps of:

- evaluating the current data transmission requirements in the user equipment, and

- setting a first bit in the Packet Data Unit in dependence of the evaluation of the current data transmission requirements, characterised by the step of: - setting at least a second bit in the Packet Data Unit indicating a priority of a data transmission requirement.

8. The method according to claim 7, wherein

- the evaluation of the current data transmission requirement is evaluation of the current data transmission load.

9. The method according to claim 7 , wherein

- the second bit indicates that the user equipment has control signalling to transmit.

10. The method according to claim 7, wherein - the second bit indicates that the user equipment has prioritized user data to transmit.

11. The method according to claim 7, wherein

- further bits are provided in the Packet Data Unit for indicating various levels of priority and wherein the highest level of priority is dedicated for control signalling.

12. A radio base station comprising means for performing any of the methods according to claims 2 to 6.

13. A user equipment comprising means for performing any of the methods according to claims 7 to 11.