WO2006126461A1

WO2006126461A1 - Communication terminal apparatus, network apparatus and communication method

Info

Publication number: WO2006126461A1
Application number: PCT/JP2006/310059
Authority: WO
Inventors: Yasuo Kubo
Original assignee: Matsushita Electric Industrial Co., Ltd.
Priority date: 2005-05-23
Filing date: 2006-05-19
Publication date: 2006-11-30
Also published as: JPWO2006126461A1

Abstract

A communication terminal apparatus, a network apparatus and a communication method that suppresses the degradation of the throughput so as to improve the throughput of the whole system. A mobile terminal (100) comprises a MAC-hs reset frequency determining part (104) that counts the occurrences of MAC-hs reset during HSDPA communication and that determines a MAC-hs reset frequency from the number of occurrences of MAC-hs reset per unit time; a channel switch deciding part (106) that compares the measured MAC-hs reset occurrence frequency with a threshold value stored in a channel switch threshold value information storing part (105); and a channel switch function part (107) that outputs, in accordance with a result of the comparison, a switch request for switching from an HSDPA channel to a separate channel (DPCH). When the MAC-hs reset occurrence frequency is greater than the threshold value, the data transmission is switched from the HSDPA channel to the DPCH channel.

Description

Specification

COMMUNICATION TERMINAL DEVICE, NETWORK DEVICE, AND COMMUNICATION METHOD

Technical field

TECHNICAL FIELD [0001] The present invention relates to a communication terminal device, a network device, and a communication method, and more particularly to a communication terminal device, a network device, and a communication method used in a communication system adopting an HSDPA (High Speed Downlink Packet Access) method.

Background art

[0002] Conventionally, in the field of wireless communication systems, a plurality of high-speed and large-capacity downlink channels are used in addition to a communication method in which packets are transmitted to a communication terminal device using a dedicated channel (DPCH: Dedicated Physical Channel). A communication method called HSDPA, which is shared by multiple communication terminal devices and performs high-speed packet transmission on the downlink, is standardized.

[0003] In such an HSDPA system, the base station apparatus indicates the modulation method and coding rate of packet data that can be demodulated in a communication terminal apparatus called CQI (Channel Quality Indicat or Adaptive Modulation Request). A signal is transmitted from the communication terminal device. The base station apparatus that has received the CQI performs scheduling using the CQI that has also been sent to each communication terminal apparatus, and selects an optimal modulation scheme and coding rate. The base station apparatus modulates and encodes transmission data using the selected modulation scheme and coding rate, and transmits the data to each communication terminal apparatus based on the scheduling result. This enables HSDPA to transmit a large amount of data from the base station device to the communication terminal device compared to DPCH in order to adaptively change the transmission rate according to the radio wave propagation environment.

[0004] In this HSDPA system, the communication terminal apparatus transmits a determination result as to whether the downlink is transmitted using HSDPA or DPCH (for example, Non-Patent Document 1). ). In other words, the communication terminal device selects, in General capabilities, the ability to transmit the downlink using HSDPA (REL-5) or DPCH (R99 or REL-4), and bases the selected result. Report to the host device via the station device. HSDP A can transmit a large amount of data compared to DPCH, and system throughput In general, communication terminal equipment chooses HSDPA over DPCH.

[0005] Further, in this HSDPA system, a communication terminal apparatus transmits a downstream packet called HS-PDSCH (High Speed Physical Downlink Shared Channel) to HS-DPCCH (Dedicate Physical Control Channel (uplink) for HS-DSCH). Is transmitted with an ACKZNACK signal or CQI signal indicating whether or not it has been received (for example, Non-Patent Document 2). In this method, HS—DPCCH is code-multiplexed with DPCCH (Dedicated Physical Control Channel) and DPDC H (Dedicated Physical Data Channel).

[0006] FIG. 5 is a diagram showing a user plane protocol configuration when HSDPA is applied. In the figure, a protocol implemented in a mobile station apparatus, a base station apparatus, and a control station apparatus that controls the base station apparatus is shown.

[0007] Among the protocols shown in FIG. 5, RLC (Radio Link Control) is a selective retransmission type retransmission control protocol described in Non-Patent Document 1, and is implemented in a mobile station apparatus and a control station apparatus. MAC—hs (Medium Access Control used for high speed) is a protocol that performs processing such as scheduling of downlink data transfer and retransmission control using HARQ (Hybrid-Automatic Repeat reQuest). Mounted on station equipment. HS-DSCH FP (High Speed Downlink Shared Channel Frame Protocol) is a protocol that performs flow control between the MAC-hs of the base station device and the RLC of the control station device. To be implemented.

[0008] HSDPA, which is a downlink high-speed packet transmission method, is a common channel used by multiple users competing, and switching between dedicated channels and HSDPA channels depends on the amount of user data and the quality of the communication line. Done.

[0009] As one of the causes of throughput degradation in HSDPA, RLC retransmission control by resetting MAC-hs can be considered. In normal times, HSDPA performs retransmission control using HARQ, which improves the throughput of retransmission earlier than RLC retransmission control. However, when the mobile station moves from cell to cell, MAC-hs reset is performed, and RLC retransmission control may work, which causes throughput degradation. However, at present, channel control methods that reflect throughput degradation due to MAC—hs reset are considered.

[0010] As another method, for example, in Patent Document 1, a common channel other than HSDPA is used. Switching control based on the number of transitions between cells and sectors between the cell and the individual channel is under consideration. When a transition between cells 'sectors occurs during communication, the communication is stopped on the common channel and communication is resumed after the broadcast information is acquired in the transition destination cell' sector. It is possible to move between cell sectors while maintaining communication. For this reason, this method measures the number of transitions between cell 'sectors in a mobile station communicating on a common channel, and transitions to an individual channel when a certain threshold is exceeded, thereby eliminating communication downtime and improving throughput. It can be made.

Patent Document 1: “3GPP, TS 25.306 V5.5.0 5.1”

Non-Patent Document 2: "3GPP, TS 25.213 V5.3.0 4.2.1"

Patent Document 1: Japanese Patent Application Laid-Open No. 2004-172890

Disclosure of the invention

Problems to be solved by the invention

[0011] In such a conventional wireless communication system, channel switching based on the amount of data of the user and the quality of the communication line cannot be used for other factors such as a moving speed that reduce throughput.

[0012] In addition, regarding switching control to an individual channel based on the number of transitions between cells and sectors, since handover is performed at the time of transition between cells' sectors in the HSDP A channel, communication such as acquisition of broadcast information in other common channels is performed. There is no downtime. For this reason, HSDPA channel power is not meaningful for switching to individual channels, and cannot be applied to switching based on the number of transitions between cells and sectors.

[0013] For this reason, there is a problem that throughput degradation due to retransmission by RLC is very large in a situation where MAC-hs resets frequently occur.

[0014] The present invention has been made in view of the strong point, and provides a communication terminal device, a network device, and a communication method that can suppress throughput deterioration due to retransmission in RLC and can improve the throughput of the entire system. The purpose is to provide.

Means for solving the problem

[0015] The communication terminal apparatus of the present invention includes means for transmitting data by HSDPA, and DPCH. Data transmission means, MAC-hs reset occurrence frequency detection means, and when the detected MAC-hs reset occurrence frequency is greater than a predetermined threshold, the data transmission is switched to switch to DPCH for HSDPA power. A configuration including the means.

[0016] The network device of the present invention comprises: means for transmitting data to the communication terminal apparatus in its own cell by HSDPA; means for transmitting data to the communication terminal apparatus by DPCH; Detecting means for detecting the occurrence frequency of the MAC-hs reset of the communication terminal device, and transmitting data from the HSDPA to the communication terminal device having the detected MAC-hs reset occurrence frequency greater than a predetermined threshold. A configuration with a switching means to switch to DPCH is adopted.

[0017] The communication method of the present invention includes a step of detecting the occurrence frequency of MAC—hs reset during HSDPA communication, and data transmission from HSDPA to DPCH when the occurrence frequency of detected MAC—hs reset is greater than a predetermined threshold. And switching to.

The invention's effect

[0018] According to the present invention, it is possible to suppress throughput degradation and improve the reception efficiency and throughput of the entire system.

Brief Description of Drawings

FIG. 1 is a block diagram showing a configuration of a mobile communication system according to Embodiment 1 of the present invention.

FIG. 2 is a block diagram showing a configuration of a mobile terminal according to Embodiment 1 above

FIG. 3 is a diagram for explaining generation of MAC-hs reset at the time of transition between cells' sectors according to the first embodiment.

FIG. 4 is a block diagram showing a configuration of a mobile communication system according to Embodiment 2 of the present invention.

FIG. 5 is a diagram showing a user plane protocol configuration when HSDPA is applied. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0021] (Embodiment 1)

FIG. 1 is a block diagram showing the configuration of the mobile communication system according to Embodiment 1 of the present invention. Embodiment 1 is an example in which a mobile terminal has a function of measuring the occurrence frequency of MAC-hs reset. In FIG. 1, a mobile communication system includes a plurality of mobile terminals (UE: User Equipment) 100 and a plurality of radio base station apparatuses (hereinafter referred to as Node-B) 200 that perform radio communication with the mobile terminals 100. And a radio network controller (RNC: Radio Network Controller) 300 that controls the Node—B200.

[0023] When HSDPA is applied to this mobile communication system, a handover (Hand Over) is performed when moving between UE100 power Node-B200.

FIG. 2 is a block diagram showing a configuration of the mobile terminal 100.

In FIG. 2, mobile terminal 100 includes antenna 101, RF unit 102, signal processing unit 103, MA C-hs reset frequency measurement unit 104, channel switching threshold information storage unit 105, channel switching determination unit 106, and A channel switching function unit 107 is provided.

The RF unit 102 performs wireless reception processing such as down-conversion and A / D conversion on the signal received via the antenna 101 and outputs the result to the signal processing unit 103. Further, the signal input from the signal processing unit 103 is subjected to predetermined radio transmission processing such as up-conversion, and is transmitted via the antenna 101.

[0027] The signal processing unit 103 demodulates the signal input from the RF unit 102, and performs modulation processing on the transmission data from the channel switching function unit 107 using a specified modulation scheme.

[0028] The MAC-hs reset frequency measurement unit 104 counts the number of times MAC-hs reset occurs during HSDPA communication, and measures the MAC-hs reset frequency based on the number of occurrences per unit time. The occurrence of MAC-hs reset increases when the UE is located at the boundary (cell edge) of the HSDPA serving cell or when the reception quality is poor.

[0029] Channel switching threshold information storage section 105 stores a channel switching threshold calculated by a brute force experiment or the like.

The channel switching determination unit 106 compares the measured MAC-hs reset occurrence frequency with the threshold stored in the channel switching threshold information storage unit 105.

[0031] Channel switching function section 107 outputs a switching request for switching to the HSDPA channel power individual channel (DPCH) according to the determination result.

The operation of the mobile communication system configured as described above will be described below.

FIG. 3 is a diagram for explaining occurrence of MAC-hs reset at the time of transition between cells and sectors. In FIG. 3, Node B # 1 and Node # 2 are base station apparatuses (hereinafter referred to as base stations) that perform radio communication with the mobile terminal 100, and are cells that provide HSDPA services (HSD PA serving cells). ) 400.

[0035] Mobile terminal 100 power When moving from NodeB # 1 to NodeB # 2, the inter-sector transition occurs in area A1, and inter-cell transition occurs in area A2. In the inter-sector transition of A1, Node B does not change, so MAC—hs reset does not occur. In A2 inter-cell transition, Node B transitions to NodeB # 1 and NodeB # 2, resulting in MAC-hs reset, RLC retransmission control, and a decrease in throughput. When cell-to-sector transition occurs during communication using dedicated channels, the transition is performed without interruption due to the soft node over (SHO) process.

The mobile terminal 100 stores a channel switching threshold value based on the MAC-hs reset occurrence frequency in the channel switching threshold information storage unit 105 in advance. An appropriate value is set as the threshold for channel switching by force simulation. Note that if the threshold setting level is too high, channel switching is difficult to perform and this control cannot be effective. On the other hand, if the threshold setting level is too low, switching from HSDP A to the dedicated channel (DPCH) is easily performed, making it difficult for the mobile terminal 100 to receive the HSDPA service. Here, a mode in which a plurality of threshold values are stored in the channel switching threshold value information storage unit 105, and arbitrary threshold values are dynamically selected and used by a mode setting by the user or an instruction from the RNC may be used.

[0037] By the way, conventionally, switching to a common channel power individual channel has been performed according to the number of cell-sector transitions. In this embodiment, we focus on the HSDP A specification that does not switch from the common channel to the dedicated channel based on the number of transitions between cells and sectors as in the conventional example, and based on the frequency of MAC-hs reset occurrence. It is characterized by switching from HSDP A channel to individual channel. In other words, in HSDPA, there is no handover at the time of transition between sectors, and MAC-hs reset does not occur, but handover is performed at the time of transition between cells, and MAC-hs reset occurs. HSDPA also stipulates that a predetermined flag should be set when a M AC—hs reset occurs. It is only necessary to count the number of times it has been set up. If the buffer can be shared between cells, MAC-hs reset will not occur at the time of cell-to-cell transition. Because it is large, it is not currently conducted.

[0038] The signal processing result by the signal processing unit 103 is input to the MAC-hs reset frequency measurement unit 104, and the MAC-hs reset frequency measurement unit 104 checks the flag and performs MAC associated with cell transition during HSDP A communication. — Measures the occurrence of hs reset and outputs the measured frequency of occurrence to channel switching determination unit 106. The channel switching determination unit 106 compares the input occurrence frequency with the threshold stored in the channel switching threshold information storage unit 105, and when the occurrence frequency exceeds the threshold, switches to the HSDPA channel power individual channel. Is determined to be necessary.

Channel switching function section 107 outputs a switching request for switching to HSDPA channel power individual channel (DPCH) according to the determination result. This channel switching request is notified to the network via the signal processing unit 103 and the RF unit 102. On the network side, when this channel switching request is received, the mobile terminal 100 that has transmitted the channel switching request performs control to switch the HSDP A channel power to an individual channel. Specifically, the network receives a channel switching request transmitted from the mobile terminal 100, decides to switch to the HSDPA channel channel dedicated channel communication method, and outputs to the Node B200. The dedicated channel (DPCH) may be any channel as long as it is a channel other than the HSDPA channel.

Thus, according to Embodiment 1, when the MAC-hs reset occurrence frequency is greater than the threshold, the data transmission is switched from the HSDPA channel to the DPCH channel, so that the own device is in the vicinity of the cell edge and the cell HSDPA channels are automatically switched to dedicated channels in situations where MAC-hs resets occur frequently, such as when there are frequent movements between channels or when the propagation environment is relatively fluctuating. By switching to its own channel, its own equipment can increase the margin for allocating HSDPA channels to other mobile terminals, and improve the overall system reception efficiency and throughput. HSDPA is a device that performs high-speed communication on the down line. There is real intention to take a lot of the last. From this point of view, a mobile terminal in an environment where MAC-hs reset occurs frequently increases the number of HSDPA channels allocated to other mobile terminals by descending to the dedicated channel, resulting in an improvement in overall system throughput. be able to.

[0041] When MAC-hs reset occurs frequently, retransmission control is required regardless of whether data is transmitted on the HSDPA channel or data is transmitted on the DPCH channel, so that there is no significant difference. Rather, by staying in the HSDP A channel, there is a possibility that wasteful power consumption may increase due to MAC-hs reset and accompanying rewrite operation to the buffer, but this can be prevented.

[0042] Also, according to the present embodiment, switching control to an individual channel can be realized only by changing the configuration of the mobile station apparatus, and the existing radio communication system such as the base station apparatus and the control station apparatus can be realized. I don't have to keep track of the changes!

[Embodiment 2]

FIG. 4 is a block diagram showing the configuration of the mobile communication system according to Embodiment 2 of the present invention. The same components as those in FIG. The second embodiment is an example in which the channel switching device on the network side has a function of measuring the occurrence frequency of MAC-hs reset.

In FIG. 4, a channel switching device 500 includes an RNC function unit 501, connected to a network, a base station function unit 502 that performs radio communication with a plurality of mobile terminals 600, a channel switching threshold information storage unit 503, a channel A switching determination unit 504 and a channel switching function unit 505 are provided.

[0045] The RNC function unit 501 is connected to the base station function unit 502, and performs outgoing / incoming connection control, call termination control, handover control, and the like for the base station function unit 502.

Base station function section 502 receives transmission data from RNC function section 501 that is an upper layer, performs scheduling, and wirelessly transmits the transmission data to mobile terminal 600 according to the scheduling result. In addition, the base station function unit 502 determines a mobile station and transmission rate (for example, coding rate, modulation scheme, spreading factor, transmission power, etc.) that can be transmitted from the mobile terminal 600 in its own cell, and assigns it. Do. [0047] Channel switching threshold information storage section 503 stores a channel switching threshold calculated by a brute force experiment or the like.

The channel switching determination unit 504 compares the measured MAC-hs reset occurrence frequency with the threshold stored in the channel switching threshold information storage unit 503.

[0049] Channel switching function section 505 outputs a switching request for switching to the HSDPA channel power individual channel (DPCH) according to the determination result.

Hereinafter, the operation of the mobile communication system configured as described above will be described.

[0051] It is stipulated that each mobile terminal 600 connected to the base station function unit 502 sets a predetermined flag for occurrence of MAC-hs reset accompanying cell transition during HSDPA communication. The mobile terminal 600 that has set this flag transmits this flag information to the base station function unit 502 at an appropriate timing set in advance. The MAC-hs reset occurrence flag information transmitted from each mobile terminal 600 to the base station function unit 502 is passed to the RNC function unit 501.

On the other hand, channel switching apparatus 500 stores in advance channel switching threshold information based on the frequency of occurrence of MAC-hs reset in channel switching threshold information storage section 503.

The RNC function unit 501 outputs the flag information indicating the occurrence of MAC-hs reset transmitted from each mobile terminal 600 connected to the base station function unit 502 to the channel switching determination unit 504. Channel switching determination section 504 counts the number of MAC-hs reset occurrence flags transmitted from each mobile terminal 600, calculates the occurrence frequency from the count, and calculates the occurrence frequency and channel switching threshold information storage section 503. The mobile terminal 600 whose occurrence frequency exceeds the threshold is determined to need to be switched to the HSDPA channel power individual channel.

[0054] The channel switching function unit 505 sends a switching request for switching the HSDPA channel power to the dedicated channel (DPCH) to the mobile terminal 600 whose occurrence frequency exceeds the threshold according to the determination result through the base station function unit 502. Notice. When the corresponding mobile terminal 600 receives this channel switching request, the channel switching function unit 601 switches from the HSDPA channel to the individual channel. The dedicated channel (DPCH) may be any channel other than the HSDPA channel.

[0055] Thus, according to Embodiment 2, channel switching apparatus 500 is provided with each mobile terminal 600. The MAC-hs reset occurrence status is ascertained, and the MAC-hs reset occurrence frequency is greater than the threshold. The mobile terminal 600 is notified of a channel switching request, and the corresponding mobile terminal 600 uses the channel switching function unit 601 to configure the HSDP A channel. To the DPCH channel, a mobile terminal with frequent MAC-hs reset can be switched from the HSDP A channel to the dedicated channel, and switching to the dedicated channel can afford to allocate the HSDP A channel to other mobile terminals. And the reception efficiency and throughput of the entire system can be improved.

[0056] Also, in the second embodiment, since the dedicated channel switching control is performed on the network side, more appropriate dedicated channel switching control can be performed for individual mobile terminals based on the HSDPA usage status of the entire system. it can. For example, when it is judged that it is suitable for the system to transmit with HSDPA as it is, such as when there is a relatively large HSDP A channel in the entire system, by lowering the threshold for switching from the HSDP A channel to the DPCH channel, Reduce switching to individual channels. Alternatively, do not switch from the HSDPA channel to the DPCH channel. Conversely, when there is relatively little room in the HSDPA channel in the entire system, adaptive control such as increasing the threshold to facilitate switching to an individual channel becomes possible. In addition, Embodiment 2 can realize switching control to an individual channel only by changing the configuration on the network side, and there is an effect that the change of the components of the mobile terminal can be minimized.

In the second embodiment, the flag to be set when the MAC-hs reset occurs is transmitted to the mobile terminal 600 network side, and the occurrence frequency is calculated on the network side. Thus, the occurrence frequency can be calculated on the mobile terminal 600 side, and the calculated occurrence frequency information can be sent to the network side. This has the effect of reducing the processing load on the network side.

The above explanation is an illustration of a preferred embodiment of the present invention, and the scope of the present invention is not limited to this. For example, any means of changing from DPCH channel to HSDP A channel can be used.

[0059] In addition, the power of switching from the HSDP A channel to the DPCH channel is not limited to this. If the HSDPA channel is switched to a communication method other than HSDPA, the DPCH Not limited to channels ヽ.

[0060] Also, in each of the above embodiments, the names terminal device, channel switching device, and mobile communication system are used, but this is for convenience of explanation, and the communication terminal device, base station device, wireless transmission device, Of course, you can use packet communication method!

[0061] Further, the type, number, connection method, and the like of each circuit unit constituting the mobile terminal and the channel switching device are not limited to the above-described embodiments.

[0062] The communication method described above is also realized by a program for causing this communication method to function. This program is stored in a computer-readable recording medium.

[0063] Based on Japanese Patent Application No. 2005-150014 filed on May 23, 2005. This content [all included here.

Industrial applicability

The communication terminal device, the network device, and the communication method according to the present invention have an effect of suppressing the throughput reduction of the entire system, and in particular, a wireless that applies the HSDPA method that communicates packets at high speed via a wireless line. Useful in communication systems.

Claims

The scope of the claims

[1] means for transmitting data by HSDPA;

Means for transmitting data via DPCH;

MAC — detection means to detect the frequency of occurrence of hs reset,

Switching means for switching data transmission from HSDPA to DPCH when the detected frequency of the MAC—hs reset is greater than a predetermined threshold;

A communication terminal device comprising:

[2] Means for transmitting data to the communication terminal apparatus in the own cell by HSDPA, means for transmitting data to the communication terminal apparatus by DPCH, and generating MAC-hs reset of the communication terminal apparatus A detecting means for detecting a frequency, and a switching means for switching data transmission of the communication terminal apparatus from HSDPA to DPCH for a communication terminal apparatus in which the detected MAC-hs reset occurrence frequency is greater than a predetermined threshold value.

A network device comprising:

[3] Detecting the MAC-hs reset frequency during HSDPA communication,

Detected MAC—switching data transmission from HSDPA to DPCH when the frequency of occurrence of hs reset is greater than a predetermined threshold

A communication method.