Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W72/00—Local resource management
  • H04W72/50—Allocation or scheduling criteria for wireless resources
  • H04W72/52—Allocation or scheduling criteria for wireless resources based on load
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L47/00—Traffic control in data switching networks
  • H04L47/10—Flow control; Congestion control
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W28/00—Network traffic management; Network resource management
  • H04W28/02—Traffic management, e.g. flow control or congestion control
  • H04W28/0289—Congestion control
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W28/00—Network traffic management; Network resource management
  • H04W28/02—Traffic management, e.g. flow control or congestion control
  • H04W28/10—Flow control between communication endpoints
  • H04W28/14—Flow control between communication endpoints using intermediate storage
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
  • H04W88/12—Access point controller devices

Definitions

• the present invention relates to adaptive radio channel switching in a radio network in order to optimise the overall radio network capacity. Especially, the present invention relates to adaptive down and up switching between dedicated channels .
• Data traffic speeds using packet switched transmission over cellular systems like WCDMA can differ due to various reasons like: a) round trip delay and error rate in the radio network; b) slow or no radio bearer change when having bursty traffic in the radio downlink or uplink.
• the throughput for these cases can be improved using radio adapted TCP software and/or proxy servers or using HSDPA/HSUPA which reduces the round trip delay and radio bearer switching time.
• the speed can also be limited due to the remote FTP server speed/access limitations.
• the maximum access speed per user may be limited at these servers as many users may try to access this server at the same time, e.g. during some broadcasting or in general the maximum access speed may be limited.
• the same low speeds have been noticed.
• the allocated dedicated channel DCH supported 384 kbps although the average throughput was approximately 100 kbps and a 128 kbps DCH would have been sufficient in order to achieve the same average download speed. Allocating the wrong dedicated channel DCH for such medium data speeds results in: 1) Unnecessary digital line (Iub) capacity occupation.
• DCH digital line capacity is reserved for this dedicated channel and cannot be given to other users.
• RNC Radio Network Controller
• the patent application US 2004/0097191 describes a method of switching, by monitoring the traffic, from a current common channel to a dedicated channel for a user equipment.
• the method is used in a UMTS Terrestrial Radio Access Network (UTRAN) .
• UTRAN UMTS Terrestrial Radio Access Network
• the patent application US 2003/0012217 Al describes channel-type switching to a common channel based on common channel load and considers mainly optimized channel switching between common and control channels.
• the prior art documents relate to switching algorithms for switching between control and dedicated channels and between dedicated and shared channels, wherein the switching is made in dependence of throughput, buffer load, etc. Further, these applications relate to bursty traffic and describe how to avoid ping pong effects in the switching between common and dedicated channels.
• An object with the present invention is to provide down and up switching between dedicated channels (WCDMA) using e.g. measured data throughput and buffer load in e.g. the RNC as switching parameters .
• WCDMA dedicated channels
• Another object of the invention is to provide a down and up switching between shared dedicated channels as a function of the data throughput and buffer load in e.g. the RNC or Node B.
• Yet another object of the invention is to provide digital line capacity allocation/reservation switching depending on the dedicated channel and therefore also depending on the user throughput and buffer load.
• the present invention relates to adaptive radio channel switching between dedicated channels for WCDMA and shared channels for HSDPA/HSUPA radio systems in order to adapt to the user end-to-end packet switched data traffic requirements and with this to optimise the overall radio network capacity.
• the inventive switching method adds new functionalities in the radio and transport network resource managements by monitoring the user/users buffer and throughput information as available in the Radio Network Controller, RNC, and/or Node B.
• the invention optimises the overall network capacity as unnecessary reserved codes and digital line capacity, Iub and Iur, can get free for other users .
• the present invention allows adapting the channel bit rate allocation to the user's experienced end-to-end PS data throughput by monitoring the data throughput and buffer condition in the RNC and/or node B and applying the appropriate radio channel configuration and Iub reservetions for this user.
• This will be beneficial to all users in the radio network as the total radio resource, i.e. available codes, and digital line capacity will be optimised and the total achieved network throughput will be higher.
• the present invention relates to a method and a Radio Network Controller for adaptive radio channel switching between dedicated channels in an UMTS network.
• Figure 1 schematically illustrates a UMTS network, according to prior art, comprising a core network and a
• FIG. 2 schematically shows an embodiment of a radio resource management with an adaptive channel switching (ACS) algorithm implemented in the RNC;
• ACS adaptive channel switching
• Figure 3 schematically illustrates a possible adaptive channel switching, ACS, implementation for WCDMA
• Figure 4 schematically shows how the buffer and throughput values vary over time for WCDMA
• Figure 5 schematically illustrates a possible adaptive channel switching, ACS, implementation for HSDPA
• Figure 6 schematically shows how the buffer and throughput values vary over time for HSDPA.
• Node B Base Transceiver Station BTS.
• Logical node in the 3GPP RNS responsible for radio transmission/ reception in one or more cells to and from the UE. Terminates the Iub interface towards the RNC.
• UE • User Equipment e.g. mobile terminal, phone and all peripherals
• channel is applied to both DCH configurations and HSDPA/HSUPA (HS-DSCH/HS- USCH) configurations.
• FIG. 1 illustrates schematically a Universal Mobile Telecommunications System, UMTS, network 10 according to prior art.
• the UMTS network 10 comprises a core network 20 and a UMTS Terrestrial radio Access Network, UTRAN, 30.
• the UTRAN 30 comprises a number of Radio Network Controllers, RNCs, 32 each of which is coupled to a set of neighbouring Base Transceiver Stations, BTSs, 34, also called Node Bs.
• BTSs Base Transceiver Stations
• Each Node B 34 is responsible for a given cell and the controlling RNC 32 is responsible for routing user and signal data between that Node B 34 and the core network 20. All of the RNCs 32 are coupled to one another.
• FIG. 1 also illustrates a mobile terminal or a user equipment 40.
• the core network 20 comprises a serving GPRS Support node, SGSN, 22 and a GPRS Gateway Support Node, GGSN, 24.
• the SGSN 22 and the GGSN 24 provide packet switched data services to the user equipment 40 via the UTRAN 30.
• the invention relates to adaptive channel switching for WCDMA and HSDPA/HSUPA.
• WCDMA is a 3G technology that increases data transmission rates compared to GSM systems by using the CDMA air interface instead of TDMA.
• the HSDPA/HSUPA is an enhancement to the WCDMA 3G technology that increases the downlink/uplink speed by applying different modulation and coding techniques as well as multiple antennas .
• Figure 2 schematically shows an embodiment of a radio resource management with an adaptive channel switching
• the adaptive channel switching, ACS is an additional function that complements existing channel switching features within the serving RNC, SRNC.
• FIG. 2 illustrates a radio network controller, RNC, 32 comprised in a radio and transport network, such as a UTRAN 30.
• the RNC 32 comprises a congestion control means 50 communicatively connected to a radio admission control means 52, means for adaptive channel switching, ACS, 54.
• the ACS means 54 is communicatively connected to the radio admission control means 52 and an Iub admission control means 56.
• the congestion means 50, the radio admission control means 52, the ACS means 54 and the admission control means 56 are communicatively connected to a monitoring means 58.
• An Iub 60 is provided as an interface between the RNC 32 and a Node B 34, whereby a channel set up request can be sent from the Node B 34 to the RNC 32.
• the monitoring means is configured to monitor e.g. DL codes, throughput, buffer load, radio load, transmit power etc.
• the congestion means is configured to imitate a channel switching from a dedicated channel to a common channel if congestion exists, i.e. if not enough bandwidth to support the current traffic load is available.
• the admission control means is configured to estimate the load and fill up the system to its load limits. If, for example, the downlink or uplink limit threshold. is exceeded, a new RAB may not be admitted.
• the function can be located in radio resource control in the RNC.
• the admission control can be configured to decide on the RAB during setup and can also switch user/users in case resources need to be released for new users.
• Embodiments of the invention may comprise means 62 for other dependencies, which means 62 can be communicatively connected to the Iub admission control means 56. All of the admission controls run in parallel.
• the ACS channel switch is approved by the radio/digital admission control.
• the ACS IuB admission control 56 although connected with the arrow "B" to the ACS 54 is or could be also connected directly to the Congestion Control 50 and/or Admission Control 52. For the present invention it is of importance that the ACS connects to 50, 52 and 56 directly in order to invoke channel switching in the radio and digital domain if necessary.
• Iub admission control means 56 could be also seen as some other future/existing function which allows channel switching after getting some channel switch request/indication from the ACS.
• the radio resource management can further comprise means for soft and softer handover, and means for coverage triggered channel switching.
• the means for handover can be configured to imitate a channel switching if otherwise a link cannot be established.
• the means for coverage triggered channel can be configured to reconfigure the radio bearer when the coverage limit for the current bearer is reached.
• the ACS means 54 decides the best channel configuration depending on the monitored throughput and buffer condition for each PS connection.
• the decision can be supported by monitored measurements at the mobile terminal 40, e.g. through measurements at the mobile terminal 40. For example, throughput values at the mobile terminal 40 can be measured. If the throughput and buffer is below/above a predetermined threshold value, the ACS 54 indicates that down/up switching is required.
• Every channel switch is approved by the radio/digital transport-network admission control means 52 and 56 before carried out, as indicated by the arrows B in figure 2.
• the threshold values for switching the channel preferably include some hysteresis in order to avoid the so called ping pong effect, i.e. in order to avoid too early switches due to short bursty fluctuations. Moving averaging can be applied to the measured throughput and buffer values.
• the ACS means 54 and the ACS algorithm are configured to operate in parallel to other radio resource management- means and algorithms which for example handles new packet transmission, handover control, power control, congestion control, etc.
• the actual switching of the channel is done by carrying out a radio bearer reconfiguration as described in 3GPP TS25.331, Technical Specification Group Radio Access Network; Radio Resource Control (RRC) ; Protocol Specification, and will therefore not be described in more detail .
• RRC Radio Resource Control
• the present invention applies to UMTS networks, WCDMA, where different radio channels can be assigned in order to deliver different bit-rates to the user.
• WCDMA Wideband Code Division Multiple Access
• this considers mobiles which allow data rates larger than 64 kbps .
• the invention includes updates to HSDPA and HSUPA.
• Figure 3 schematically illustrates how an embodiment of the inventive ACS algorithm may be implemented in order to switch the data rate between dedicated channels, e.g. 384 kbps DCH » 128 kbps DCH • 64 kbps DCH, and down to lower bit rate common channels, Random Access Channel RACH /
• the physical channel and the transport channel parameters of the radio bearer are reconfigured using the standardised Radio Resource Control, RRC, procedure.
• RRC Radio Resource Control
• AAL2 allocated / reserved digital line
• Transport network switching is possible with ATM AAL2 layer.
• the ACS algorithms for the downlink and uplink are independent of each other. For mobile terminals which only support 64 kbps in the uplink, the uplink uses a fixed Radio Access Bearer, RAB, configuration.
• RAB Radio Access Bearer
• the upper and lower threshold values also, like for the buffer, depend on the currently allocated DCH (throughput) .
• a moving average may be applied to the monitored throughput and buffer values in order not to switch too early due to some short bursty fluctuation in the traffic, whereby the so called ping pong effect can be avoided.
• the threshold values may be set relative to the upper throughput values of the current channel, e.g. upper threshold value 90% of maximum throughput value of current channel. If the highest / fastest channel has been reached no switching will occur.
• An embodiment of the inventive method implemented for WCDMA comprises the steps of (cf . figure 3) :
• RNC RNC, SRNC) ;
• step 102 checking if buffer and throughput value is below a lower threshold value; 104 if buffer and throughput value is below a lower threshold value, increasing the channel and repeating from step 102;
• step 108 if buffer and throughput is above an upper threshold value, decreasing the channel and repeating from step 106;
• step 110 if buffer and throughput is not above an upper threshold value, repeating from step 102; and 112 terminating or releasing the PS connection.
• Fig 4 schematically shows how the buffer and throughput values vary over time for WCDMA.
• HSDPA/HSUPA the users in a cell can get allocated a HS-PDSC (high Speed Physical Downlink Shared Channel) at the Controlling RNC, CRNC.
• the Medium Access Control-high speed, MAC-hs, scheduler (not shown) is located in the Node B, which serves the corresponding cell. This allows fast resource sharing in the code domain and time domain for the users accessing the same HS-DPSCs. This allows users with bursty/constant, high or medium throughputs to get the correct high average throughput with optimised radio resource sharing.
• the CRNC has to decide which HS-PDSCH has to be setup as there are 12 different classes, modulation schemes and maximum numbers of codes, available. Applying a too high HS-PDSCH class would block unnecessary codes and digital line capacity which could be used for other users.
• Figure 5 schematically illustrates how an embodiment of the inventive ACS algorithm may be implemented in order to switch the HS-PDSCH to different classes, e.g. Class 1 • Class 5 • Class 12, and down to WCDMA transmission rate.
• the allocated/reserved digital line capacity for his connection will depend on the allocated HS-PDSCH.
• the threshold values for the buffer and throughput, moving average, etc., in order to activate HS-PDSCH down or up switching should consider, like for WCDMA, the actual speed of the HS-PDSCH but also the individual speed and buffer size usage of the individual users within the shared channel. This information may be available in the RNC and/or Node B and/or reported from the mobile terminals. In order to activate the switching, the algorithm will have to consider more input parameters than for WCDMA as users with different profiles in their throughputs are sharing the same channel .
• An embodiment of the inventive method implemented for HSDPA comprises the steps of (cf . figure 5) :
• step 202 checking if buffer and throughput value is below a lower threshold value; 204 if buffer and throughput value is below a lower threshold value, increasing the HS-PDSCH and repeating from step 202;
• step 210 if buffer and throughput is not above an upper threshold value, repeating from step 202; and 212 terminating or releasing the PS connection.
• Figure 6 schematically shows how the buffer and throughput vary over time for HSDPA.

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• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Mobile Radio Communication Systems (AREA)
• Data Exchanges In Wide-Area Networks (AREA)

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• 2005
  • 2005-07-15 SE SE0501683A patent/SE529757C2/sv not_active IP Right Cessation
• 2006
  • 2006-07-07 WO PCT/SE2006/000868 patent/WO2007011281A1/en active Application Filing
  • 2006-07-07 EP EP06758050A patent/EP1908228A4/de not_active Withdrawn
• 2007
  • 2007-11-30 NO NO20076175A patent/NO20076175L/no not_active Application Discontinuation

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