WO2004088876A1

WO2004088876A1 - Data transmission method

Info

Publication number: WO2004088876A1
Application number: PCT/EP2004/000627
Authority: WO
Inventors: Mark Beckmann; Hyung-Nam Choi; Achim Luft
Original assignee: Siemens Aktiengesellschaft
Priority date: 2003-04-02
Filing date: 2004-01-26
Publication date: 2004-10-14
Also published as: DE10315058A1

Abstract

The invention relates to a method for the transmission of data on a common radio channel which is provided between a base station (BS) and a plurality of terminals (UE) in a UMTS communication system in an FDD mode as a common random access channel (HS-PR.ACH). A common control channel (HS-S-CCPCH) is used as a backward channel for a transmitter power control check for packet-oriented transmission in the event that the common random access channel is used for an upward transmission. Upon successful completion of a request for using the random access channel by means of a preamble part, the terminal transmits a message part on the common upward transmission channel. Confirmations (ACK, NACK) relating to the content of data are sent via the common control channel from the base station back to the terminal. The terminal adjusts the transmitter power on the basis of the content of the confirmation. At least one of the following parameters is used for adjustment: an output increase parameter, a repetition parameter, an output increase threshold parameter, an output decrease parameter and an output decrease threshold parameter.

Description

description

Drive data transmission

The invention relates to a method for transmitting data over a radio channel used jointly by a plurality of terminals, in which the transmission power is regulated. The invention further relates to a terminal, a base station and a communication system.

In so-called CDMA (Code Division Multiple Access) communication systems, in which all participants share the same frequency spectrum and differ only by different codes (cf. T section on explanations of terms), it can be ensured that a terminal near the base station is not the signal from distant terminals is superimposed. For this reason, a dynamic power control or "power control" is carried out. For bits are provided to the dedicated channels, special ^'with which a terminal may send an acknowledgment to the base station, for example so as to request a power increase in bad reception by the base station. On the other hand, the base station sends control bits to the respective terminals and requests each individual terminal to increase, maintain or reduce the transmission power.

However, this closed power setting only exists on the dedicated channels and not on the shared channels.

The problem with common channels is explained below using an example of a UMTS (Universal Mobile Telecommunications System) standard working communication system. For a more detailed explanation or clarification of terms, please refer to the description of the figures:

Two types of physical channels are currently specified in the FDD mode for packet data transmission for the uplink: the assigned physical data channel or "Dedicated Physical Data Channel" DPDCH and the physical random access channel or "Physical Random Access Channel" PRACH. The DPDCH allows maximum packet data transfer rates of up to 5.76 Mbps (megabits per second) as a gross data rate, but this channel is not ideal for intermittent data traffic, as is typical for packet data transfers, since it takes a relatively long time to set up and tear down the channel. The common channel PRACH, on the other hand, is designed for burst-like packet data traffic, but the PRACH only allows maximum data rates of up to 120 kbps (kilobits per second) as a gross data rate. In the case of a packet data connection to be set up between the terminal UE and the UMTS network UTRAN, depending on the current traffic situation in the radio cell and the requested quality of service or “Quality of Service * QoS of the terminal, the UTRAN either uses dedicated or shared radio resources. lokiert.

In UMTS FDD mode, the common channel PRACH enables the uplink transmission of burst-like data traffic, which can contain signaling information or user data, up to 120 kilo bits per second (kbps) as a gross data rate. Up to 16 PRACHs can be configured in a cell. The configuration of the PRACHs is in the system information blocks or "system information blocks" (SIB) 5 or 6 transmitted over the broadcast channel BCH in the cell. Within SIB 5 / SIB 6, the configuration for each PRACH is specified in the information element or "Information element" (IE) "PRACH system Information list *.

Table 1 shows the list of information elements in the "PRACH system Information list *.

Table 1: Information elements of the "PRACH system information list * according to UMTS release 5

The function or meaning of the individual information elements is as follows:

PRACH info: Here the configuration of the PRACH with regard to the available signatures, access time slots or "access slots" AS, spreading factors SF for the data part and the scrambling or for the preamble used. "Scrambling" codes signaled;

Transport Channel identity: Indicates the identity of the RACH transport channel, which is mapped to the PRACH;

- RÄCH TFS: Indicates the number of permitted transport formats for the configured RÄCH;

- RÄCH TFCS: Specifies the number of permitted transport format combinations for the configured RÄCH; - PRACH partitioning: Based on the signatures and access time slots AS configured in IE "PRACH info", up to eight access service classes ASC are signaled in this information element. A subset of the total available signatures and access time slots can be configured in each ASC, so that an ASC represents a subdivision or partition of the PRACH resources; Persistence scaling factors: Indicates the transmission probabilities with which a RACH

Transmission procedure is started by the MAC protocol layer; - AC-to-ASC mapping table: This is used to map the

Access classes to the access service classes signaled with which an "idle mode" terminal UE is able to send an initial message in the uplink; Primary CPICH DL TX power: The power with which the P-CPICH is transmitted in the radio cell is used to calculate the initial output power of the PRACH preamble;

Constant value: Constant value that is used to calculate the initial output power of the PRACH preamble;

- PRACH power offset: Specifies the parameters for the PRACH preamble transmission, such as the step size for the power setting and the maximum number of preamble retransmissions; - RACH transmission parameters: Specifies the parameters for controlling the RACH transmission at the MAC protocol layer level, further details are explained in connection with Table 4;

- AICH info: Specifies the parameters for the respective PRACH associated AICH.

In the case of a packet data transmission via the PRACH, the terminal UE first sends a preamble to the UTRAN according to a defined pattern with random components (ALOHA method) and listens to a confirmation in a precisely specified time slot on the AICH. The UTRAN can send the value 0.1, -1 here. A "0" stands for no confirmation, however also no rejection. This is the default value and is also sent if the UTRAN could not clearly assign the preamble to a terminal UE. A "1" means a confirmation (ACK) and a "-1" a rejection (NACK). The terminal only sends data on the PRACH after receiving an ACK.

The power control or power setting on the PRACH is specified as follows:

A base station sends the parameters for the use of the PRACHs configured in the radio cell on a collective call or "broadcast" channel BCH that can be received by all terminals in the radio cell. By receiving and evaluating this data, each terminal knows with which code and at what time plus a random time interval it can send on the PRACH. An initial service for sending the preamble is also communicated as a parameter. After selecting a specific PRACH, the terminal now sends a preamble with the transmission power specified as the initial power and listens to a confirmation from the network on the AICH in a specific time slot. If the request is rejected, a preamble with the initial service is sent again at another time. If the terminal only receives the default value, which means neither confirmation nor rejection, it sends the preamble again. However, this time with a transmission power increased by a delta that is also specified in the parameters. If a confirmation is given, a data packet can be sent on the PRACH depending on the performance of the last successfully transmitted preamble.

In principle, all terminals UE within a UMTS cell can use the PRACHs together for data transmission. The access of the terminals UE to a PRACH is after the "Slotted ALOHA" process is regulated, in which each terminal UE randomly selects a suitable PRACH and sends this only at the beginning of fixed time intervals, the so-called access time slots or "access slots" (AS). The use of the randomly selected PRACH depends on the access service classes ASCs (Access Service Classes), which are specified in the IE "PRACH partitioning *". Table 2 shows the parameters with which each ASC is configured. The ASCs regulate a prioritized use of PRACH.

Table 2: Information elements of "PRACH partitioning * for ASC configuration according to UMTS Release 5

The PRACH consists of a preamble part and a message part. The PRACH

The message part in turn consists of a control part and a data part. The random access transmission consists of one or more preambles of 4096 chips and length actual message. A randomly selected signature s is transmitted in the preambles. After a positive confirmation (ACK) for the correct reception of the preamble on the Acquisition Indicator Channel (AICH) by the base station, the terminal UE sends the data on the PRACH

Message part at a specified time based on the access time slots AS. FIG. 3 shows an example of a random access transmission, in which the terminal UE receives an ACK from the base station only in the second preamble. Here τ _p -p is the timing offset between two preambles, τ _p _ _{m is} the time offset or "timing offset" between the preamble and PRACH message part and τ _p - _{a is} the timing offset between the start of the uplink access time slot in which the terminal UE sends a preamble and the beginning of the corresponding downlink access time slot in which the base station sends the AICH. In the example according to FIG. 3, a transmission time length of TTI = 10 ms was selected for the PRACH message part. The following values were set for the timing offsets: τ _p _ _p = τ _p - _m = 3 AS and τ _p - _a = 1.5 AS, the length of an access time slot AS being 5120 chips.

The transmission power of the PRACH message part is set on the basis of the transmission power of the successfully sent preamble. Furthermore, the OVSF channelization codes for the PRACH message part are determined from the successfully transmitted preamble signature. There is a maximum of 16 of these signatures, which point to one of the 16 nodes in the OVSF code tree. The signatures correspond to a code with spreading factor SF = 16. Depending on the signature s, the underlying code subtree is used for the PRACH message part. The number of signatures and uplink access time slots AS that are available to a terminal UE for data transmission via the PRACH is determined by the priority of the ASCs. A maximum of 8 ASCs can be specified for a PRACH, whereby these ASCs are numbered so that the

Access service class with the number 0 or "ASC # 0" has the highest priority and the access service class with the number 7 or "ASC # 7" has the lowest priority. The higher the priority, the greater the number of available signatures and the uplink access time slots AS (summarized in the so-called RACH subchannels) can be configured in ASC. In the inactive transmission mode or in the "idle mode", the radio resource control or "radio resource control" (RRC) layer in the terminal UE selects the access service class ASC on the basis of the access classes or "access classes" (AC) , The access classes are a mechanism by which a network operator can control the access of idle mode terminals in his radio cell. A total of 16 ACs are specified, for example allowed, in the UMTS standard the access class AC15 only allows access from terminals belonging to employees of the network operator.

FIG. 1 shows a diagram for the sequence of a random access transmission to be confirmed (on the PRACH) between the terminal and a UTRAN, which runs via the base station BS. The communication system K comprises the UTRAN, the base station BS and the terminal UE.

1. Before the actual message transmission starts, the terminal UE sends a randomly selected preamble of 4096 chips in length to the UTRAN ^' . If the UTRAN corrects the preamble can detect directly, it sends a positive confirmation (ACK) on the acquisition indicator channel or "acquisition indicator channel" AICH to the terminal UE. If the UTRAN cannot correctly detect the preamble, it sends a negative confirmation (NACK) on the AICH to the terminal UE. 2. It is assumed that the UTRAN could not correctly detect the preamble sent by the UE terminal, so that a NACK is sent back on the AICH. 3. After a random waiting time, the terminal UE sends a new, randomly selected preamble to the UTRAN. This preamble is sent with a slightly higher output than in the previous preamble transmission.

4. This time the UTRAN can correctly detect the preamble sent by the UE terminal, so that an ACK is sent back on the AICH.

5. The transmission power for the following PRACH message part or "message part" is set on the basis of the transmission power of the successfully sent preamble. Terminal UE sends the message on the PRACH message part to the UTRAN as soon as possible and waits for confirmation via the S-CCPCH.

6. It is assumed that the UTRAN was able to receive the message sent by the UE terminal on the PRACH message part without errors, so that an ACK is sent back via the S-CCPCH. This completes the random access transfer.

Unfortunately, there is no further power adjustment until the end of the data transmission. The PRACH is used, among other things, for the initial connection establishment by the UE terminal. FIG. 3 shows the sequence of a random

Access transmission can be seen in UMTS-FDD mode, in which the terminal UE only receives an ACK from the base station during the second preamble transmission. A time stream is shown for the base station BS and the terminal UE, which is divided into individual access time slots AS. For the base station BS and the terminal UE, a time line is plotted, which is divided into individual time slots. The terminal UE first sends a preamble PA, then wait a time τ _p _ _p before it sends the preamble PA again with increased power, since it receives neither a positive nor a negative confirmation on the AICH from the base station. Here τ _p - _{p is} the time offset between two preambles, τ _p _ _{m is} the time offset between preamble and HS-PRACH news section and, as described below, τ _p _ _{a is} the time offset between the beginning of the Uplink access time slot in which the terminal sends a preamble and the beginning of the corresponding downlink access time slot in which the base station sends the AICH.

The base station sends a confirmation (0, +1, -1) via the AICH with a certain time offset or "time offset" TO, the length of which is equal to τ _p - _a . In the case of a positive confirmation ACK (+1), the terminal UE then begins to send the PRACH message part PRACH NT, which contains a data part D and a control part C, after a time τ _p _ _m . In the example according to FIG. 3, a transmission frame length or a transmission time interval of TTI = 10 ms was selected for the PRACH message part. The following values were set for the time offsets: X _p -p = tp-m = 3 access time slots and τ _p _ _a = 1.5 access time slots, the length of an access time slot

Is 5120 chips.

As already written, there is no further performance adjustment after the initial performance adjustment.

Starting from this prior art, it is an object of the present invention to provide a method for a closed power control on shared channels.

This object is solved by claims 1, 3, 4 and 5. Advantageous refinements are the subject of the dependent claims.

The invention is based on the idea of defining parameters by means of which power regulation can take place on a channel used by several terminals.

It is the core of the invention to use a common control channel as a return channel for a transmission power control in a packet-oriented transmission in the case of a UMTS FDD system in the event that a common random access channel is used for an uplink transmission. The proposed common uplink channel is referred to as HS-PRACH during the registration, the common control channel as HS-S-CCPCH.

After a request for use of the common random access channel by means of a preamble part has expired successfully, the terminal sends a message part on the common uplink transmission channel. Confirmations that data have been received are sent back to the terminal from the base station via the common control channel. The terminal sets the transmission power based on the content of the confirmation.

At least one of the following parameters is used for setting: a performance increase parameter, a repetition parameter, a performance increase threshold parameter, a performance decrease parameter and a performance decrease threshold parameter.

For example, in the event of a negative confirmation (NACK) after a number of receptions of a negative confirmation specified by the power increase threshold parameter, the transmission power is increased by a value determined by the power increase parameter. The repetition parameter specifies how often a transmission frame with increased performance is sent.

Similarly, if a certain number of positive acknowledgments (ACK) determined by the power reduction threshold parameter is received, the transmission power can be reduced by a value defined by the power reduction parameter.

With additional use of the HS-PRACH for an improved uplink connection, especially in the case of sudden data traffic and the distribution over a longer period of time, the performance control can be significantly improved.

A terminal or a base station which are suitable for these methods are at least equipped with a transmitting / receiving device and a processor device, which before interacting in such a way that performance can be regulated.

Further advantages and refinements of the invention are explained below with reference to figures. Show it:

1 shows the sequence of a random access transmission in UMTS FDD mode;

FIG. 2 shows a frame structure for the uplink PRACH;

Figure 3 shows the sequence of a random access transmission in UMTS FDD mode;

FIG. 4 shows the course of an increase in performance in the case of a random access transmission in UMTS FDD mode;

FIG. 5 shows the course of a power reduction in the case of a random access transmission in the UMTS FDD mode.

First of all, the terms used in the application should be explained in more detail.

1. Definitions

A communication system or communication network is a structure for exchanging data. This can be a cellular mobile radio network that works, for example, according to the GSM (Global System of Mobile Communications) standard or the UMTS (Universal Mobile Telecommunications System) standard. Terminals and base stations are generally provided in a communication system and are connected to one another via a radio interface. who connect. In the UMTS, the communication system or radio transmission network has at least base stations, here also called NodeB, and radio network control units or "Radio Network Controllers" (RNC) for connecting the individual base stations. The terrestrial radio access network or "Universal Terrestrial Radio Access Network" (UTRAN) is the radio-technical part of a UMTS network in which, for example, the radio interface is also made available. A radio interface is always standardized and defines the entirety of the physical and protocol specifications for data exchange, for example the modulation method, the bandwidth, the frequency swing, access methods, security procedures or switching techniques. The UTRAN thus comprises at least base stations and at least one RNC.

In cellular mobile radio systems, various radio transmission technologies can be provided which define how the physical connection resources are divided. In the case of UMTS, a frequency multiple access mode or Frequency Division Duplex (FDD) mode is currently provided, as well as different time multiple access modes or Time Division Duplex (TDD) modes. In the FDD mode, the data transmission of so-called "up" and "downlink" connections on different frequencies takes place by frequency multiplexing, while in the two TDD modes the data transmission of uplink and downlink on the same frequency takes place by time multiplexing.

A base station is a central unit in a communication network which, in the case of a cellular mobile radio network, serves terminals or communication terminals within a cell of the mobile radio network via one or more radio channels. The base station provides the air interface between base station and terminal ready. She takes over

Processing of radio operations with the mobile participants and monitors the physical radio connection. It also transmits the user and status messages to the terminals. The base station has no switching function, but only a supply function. A base station comprises at least one transmitting / receiving unit.

A terminal can be any communication terminal via which a user communicates in a communication system. For example, mobile terminals such as mobile phones or portable computers with a radio module are included. A terminal is often also referred to as a "mobile station" (MS) or in UMTS "user equipment" (UE).

In mobile communications, a distinction is made between two connection directions. The downlink or "downlink" (DL) denotes the direction of transmission from the base station to the terminal. The uplink or "uplink" (UL) denotes the opposite direction of transmission from the terminal to the base station.

In broadband transmission systems, such as a UMTS mobile radio network, a channel is a sub-area of an available total transmission capacity. In the context of this application, a wireless communication path is referred to as a radio channel.

In a mobile radio system, for example UMTS, there are two types of physical channels for the transmission of data: permanently assigned channels or "dedicated channels" and shared or "common channels". With dedicated channels, a physical resource is only used for the carrying information reserved for a particular terminal. The common channels can transmit information that is intended for all terminals, for example the primary common physical control channel or "primary common control physical channel" (P-CCPCH) in the downlink, or all terminals share a physical resource by each terminal may only use it for a short time. This is the case, for example, with the physical random access channel or "physical random access channel" (PRACH) in the uplink.

In the case of transmission via a "common channel" or "dedicated channel", in addition to bandwidth spreading by means of a spreading code or "channelization code" for more robust transmission, the data is also a scrambling or "scrambling" procedure for identifying a specific connection subjected. Depending on the direction of transmission, the type of channel and the radio transmission technology, different types of scrambling codes or "scrambling codes" are used.

While a bit from a data sequence is usually referred to as a symbol, a bit of a bandwidth-spread sequence is referred to as a chip.

In mobile radio systems, such as those based on UMTS, in addition to circuit-switched or "circuit switched" services, packet-oriented or "packet switched" services are also provided.

Data transmission takes place in particular in 2nd or 3rd generation mobile radio systems, such as GSM or UMTS via the radio channel in general in a predetermined time structure, the transmission frame, which is often referred to as a frame. A transmission frame thus represents the periodic basic time structure with which data is physically transmitted. In UMTS is a

Frame 10 ms. To carry out certain functions, such as channel estimation and performance control, a frame is divided into time slots, for example in UMTS into 15 time slots. A time slot is therefore a permanently assigned time segment within a transmission frame.

On the basis of the temporal structure, consisting of frames and time slots, further temporal substructures, for example subframes or "subframes", can be defined. For example, one could define a subframe in UMTS, which should comprise three time slots, so that a frame is then composed of 5 subframes.

A transmission frame length or "transmission time interval" (TTI) denotes the length of time over which data which have been encoded together due to a scrambling, e.g. a so-called "scrambling" or "interleaving", spread out over time. For example, a TTI can be specified in relation to time slots.

In particular, the transmission time interval in which data from the medium access layer or "Medium Access Layer" (MAC) (OSI layer 2, OSI: Open System Interconnection-on) to the physical layer (OSI layer 1) The form of so-called transport blocks (= combination of data packets of a fixed length). Furthermore, the transmission time interval in which the data then be physically transmitted over the air interface.

For example, in the case where TTI = 40ms applies, data from the MAC layer becomes physical every 40ms

Shift sent. On the other hand, this data is then transmitted by the physical layer within 4 frames.

2. Embodiments of the invention

2.1 Combination of the performance control parameters with shortened frame formats

A possible extension for more efficient data transmission on the HS-PRACH is the segmentation of a data packet into several smaller sections that are sent at a random point in time within a specified section. There is a confirmation of the receipt of the individual segments via the HS-S-CCPCH. If the confirmation fails within a specified time, the segment is repeated. The total length for the transmission of a packet can increase significantly. The longer a data transfer takes, the more important it becomes to use a closed performance control.

2.2 Specification of the power control parameters

If the HS-PRACH is used as an additional data connection in order to reduce the interference in the cell, according to an advantageous embodiment of an extension the secondary common control channel or "Secondary Common Control Physical Channel" (S-CCPCH), namely the one below High- speed channel or HS-S-CCPCH designated channel, used as a separate return channel for an expanded performance control during data transmission.

Efficient power control for the shared channel PRACH in UMTS FDD mode is essential for an embodiment of the method according to the invention, particularly advantageous in the case of shortened frame lengths. In the following, an embodiment with the following features is proposed:

a) Extension of the ASC with new parameters

Within the information element "PRACH system Information list * (Table 1) in the IE" PRACH partitioning * (Table 2) the ASC configuration is expanded by the following five parameters:

- A power increase parameter "PowerUp NACK Delta" (PND): Sets a delta in dBm by which the power is increased if NACK is received.

- A power increase repeat parameter "PowerUp NACK Repeat" (PNR): Sets the number of repetitions with power increase when NACK is received.

- A PowerUp Threshold (PUT): Sets the successive number of NACKs received at which the power is increased.

- A power reduction parameter "PowerDown Delta" (PDD): Sets a delta in the unit dBm, around which the

In the event of receiving ACK the performance is lowered. - A power reduction threshold "PowerDown Threshold *

(PDT): represents the consecutive number of received

ACKs that lower performance.

Table 3 shows the extended information element IE "PRACH partitioning for ASC configuration with the corresponding value ranges of the new parameters. According to an advantageous embodiment, all parameters or only a selection from them can be provided.

Table 3

Table 3

b) Performance control or performance setting on the PRACH

When a specified number of NACKs (hysteresis) are received, the data packet segment is repeated with the power increased by the value specified in the "PowerUp NACK Delta *" parameter. The repetition occurs up to the number specified in "PowerUp NACK Repeat *, before a new connection with preamble and initialized service is established (see Figure 1). Also when the default value 0 is received, the transmission power is increased the next time it is repeated. With a certain number of ACKs (hysteresis), indicated by the "PowerDown Threshold *" parameter, the power for the next data packet can be reduced.

FIG. 2 shows the frame structure for the PRACH message part. The "radio frame" of the message part comprises a time of 10 ms, which is designated TRACH in the figure. This radio frame is divided into 15 time slots S # 0 to S # 14. Each time slot contains a data part D and a control part or control part C. The control part is in turn divided into a pilot section and a transport format combination indicator section.

Only specific control information of the physical layer is sent on the control part, such as “pilot bits” for channel estimation and “TFCI bits” as a transport format combination indicator for the data part. The actual message is sent from the RACH transport channel on the data part. The number of data bits transmitted on the control and data part per frame or time slot NPilot, NTFCI, NData results from the spreading factor (SF) of the used

OVSF spreading codes (OVSF Orthogonal Variable Spreading Factor) and the modulation type BPSK (Binary Phase Shift Keying) used in the uplink. The control part is always spread with a spreading code with a spreading factor of 256, so that 10 bits are transmitted in one time slot with a length of 2560 chips. Spreading codes with a spreading factor of 32, 64, 128 or 256 are possible for the data part. This means that at least 10 bits with a spreading factor of 256 to a maximum of 80 bits with a spreading factor of 32 can be transmitted per time slot with a length of 2560 chips.

The various configurations and embodiments of the invention thus enable efficient uplink data transmission for burst-like packet data applications in the UMTS FDD mode with the aid of the PRACH which has been improved for power adaptation via the HS-S-CCPCH.

2.3 Detailed embodiments

The following assumptions apply to the following two exemplary embodiments:

- In a UMTS cell, both PRACHs and HS-PRACHs or S-CCPCHs and HS-SCCPCHs are available for more efficient data transmission in the uplink. - A terminal UE in "Connected" mode is considered, which sends a preamble on the HS-PRACH and receives an ACK on the AICH. - For the HS-PRACH the new parameters in the ASC were configured as follows:

- PowerUp NACK Delta (PND) = 3

- PowerUp NACK Repeat (PNR) = 3 - PowerUp Threshold (PUT) = 2

- PowerDown Delta (PDD) = 3

- PowerDown Threshold (PDT) = 2

Exemplary embodiment 1: increase in transmission power in the case of random access transmission

FIG. 4 shows the course of an increase in performance in the case of a random access transmission in UMTS FDD mode. The transmission power SP is plotted against the time above, specifically for the base station for the channels HS-S-CCPCH and AICH, for the terminal for the extended HS-PRACH.

The base station BS uses the AICH only as a return channel for the preamble sent by the UE terminal, while the base station BS uses the HS-S-CCPCH only as a return channel for the sent HS-PRACH.

After receiving a NACK several times, for example twice, the UE terminal sends the HS-PRACH message part HS-PRACH NT with increased transmission power. FIG. 4 shows how the terminal UE sends the HS-PRACH message part HS-PRACH NT several times and, after receiving a NACK twice from the base station BS, increases the transmission power.

The first exemplary embodiment is illustrated graphically in FIG. 4. The UE terminal sends a preamble on the HS-PRACH using the ALOHA procedure with an initial power setting. The HS-PRACH is an additional one for the dom access data transmission channel used for uplink

Data transmission based on a new subframe structure to minimize interference in the cell in the uplink. It is based on the PRACH specification shown in FIGS. 2 and 3, which has improved transmission properties.

In this example it is assumed that UTRAN sends an acknowledgment through an ACK on the AICH at the defined time of τ _p - _a = 1.5 access time slots. Thus, the terminal UE can send the actual data on the HS-PRACH at the defined time of τ _p - _m = 3 access time slots. The first data segment 1 is sent with a power derived from the power setting used in the preamble. In this example it is assumed that UTRAN confirms that this data has been received by a NACK on the HS-S-CCPCH. The first data segment 1 is therefore repeated. No change is made in the power setting, since the "PowerUp Threshold" is set to two and therefore the transmit power is not changed until the second iteration. The repeated segment is also negatively confirmed by the UTRAN by a NACK on the HS-S-CCPCH. Now, with the second repetition, there is a change in power according to the "PowerUp Delta" PND value by + 3dBm. The same procedure would also take place when the standard value 0 was received.

In this example, the UE terminal would send up to a maximum of three repetitions of the same data segment, each with increased performance, since the "PowerUp Repeat" PUR parameter is set to three and the "PowerUp Threshold" PUT has already been reached. It is in the stand the technology for the maximum performance defined for the PRACH.

The further course of the exemplary embodiment is no longer part of FIG. 4. It is assumed that UTRAN now confirms receipt of the second repetition of the data segment by an ACK on the HS-S-CCPCH. The next data segment can be sent with the same power setting. The process of a later reduction in the transmission power is illustrated in the second exemplary embodiment.

Embodiment 2: Reduction in transmission power in random access transmission

The second exemplary embodiment is shown graphically in FIG. As in FIG. 4, the transmission power SP is plotted against time, HS-S-CCPCH and AICH are again listed for the base station BS and HS-PRACH for the UE terminal.

Again the terminal UE sends a preamble on the HS-PRACH with an initial power setting according to the ALOHA method. In this example it is also assumed that UTRAN sends an acknowledgment by an ACK on the AICH at the defined point in time. The initialization process does not deviate from the standard, so that the case of an unsuccessful transmission of the preamble need not be taken into account here. As in the first example, the UE terminal can send the actual data on the HS-PRACH. In this example it is assumed that UTRAN confirms the error-free reception of the first data segment 1 by an ACK on the HS-S-CCPCH. The length of time that it takes to send the HS-PRACH message part is designated HS-PRACH TTI.

The second data segment 2 is sent by the terminal UE. No change is made in the power setting, since the "PowerDown Threshold" PDT is set to two, and therefore the transmission power in the third segment is only changed after two successively confirmed segments. The reception of the second segment is also from

UTRAN confirmed by an ACK on the HS-S-CCPCH. Now, when the third data segment 3 is sent, there is a change in power according to the value "PowerDown Delta" PDD by -3dBm. The next reduction in transmission power does not take place immediately in the subsequent confirmed data segment 4, but only after the "PowerDown Threshold" PDT has been reached again. It is also conceivable to introduce a minimum transmission power, which should not be undercut.

Even if the present invention has been described in particular with reference to examples from UMTS, it is nevertheless also to be used in a large number of different communication systems and channels. The clarification of terms in section 1 also serves as an indication of the range of use.

Abbreviations

ACK Acknowledgment AICH Acquisition Indicator Channel

ASC Access Service Class

BCH broadcast channel

CCCH Common Control Channel

CPICH Common Pilot Channel DCCH Dedicated Control Channel

DL downlink

DPDCH Dedicated Physical Data Channel

FBI feedback information

FDD Frequency Division Duplex HS-PRACH High Speed PRACH

HS-S-CCPCH High Speed S-CCPCH kbps kilo bits per second

Mbps Mega bits per second

Mcps Mega chips per second NACK negative acknowledgment

PRACH Physical Random Access Channel

QoS Quality of Service

S-CCPCH Secondary Common Control Physical Channel

SF Spreading Factor TDD Time Division Duplex

TFCI Transport Format Combination Indicator

TFL transmission frame length

TFS Transport Format Set

TM Transparent Mode TPC Transmit Power Control

TST Transmission Start Time

TSTP Transmission Start Time Probability

TTI transmission time interval TX Transmit

UE user equipment

UMTS Universal Mobile Telecommunications System

UTRAN UMTS Terrestrial Radio Access Network

Claims

claims

1. A method for transmitting data on a common radio channel, which is provided between a base station (BS) and a plurality of terminals (UE) in a communication system as a common random access channel (HS-PRACH), in which a terminal (UE ) after a positive request to be allowed to send data on the common access channel, sends data via the common random access channel (HS-PRACH) to the base station (BS), the base station (BS) sends a positive or negative confirmation of the correct one Reception or incorrect reception of this data via a common control channel (HS-S-CCPCH) to the terminal (UE)

- and the terminal (UE), depending on whether the confirmation is positive or negative, adjusts the transmission power and the transmission process by means of the following parameters: a) a first power increase parameter (PND), which specifies a value by which the power is to be increased if a negative acknowledgment (NACK) is received; b) a first retry parameter (PNR) indicating the number of times the request is sent with increased power if a negative acknowledgment (NACK) is received; c) a power increase threshold parameter (PUT), via which the successive number of negative confirmations (NACK) is set, after the reception of which the transmission power is increased; d) a performance reduction parameter (PDD) which specifies the value by which a performance is reduced in the event of receipt of a positive acknowledgment (ACK); e) a power reduction threshold parameter (PDT) which defines the successive number of positive acknowledgments (ACK) after which the power is reduced.

2. The method according to claim 1, wherein the communication system is a communication system operating according to the UMTS standard, in particular in the FDD mode.

3. Terminal (UE) with a transmitting / receiving unit and a processor unit, which cooperate for power control of the transmission power in such a way that a method according to claim 1 or 2 can be carried out.

4. Base station (BS) with a transmitter / receiver unit and a processor unit, which cooperate to regulate the power of the transmitter power in such a way that a method according to claim 1 or 2 can be carried out.

5. Communication system comprising a terminal (UE) according to claim 3 and a base station (BS) according to claim 4.