KR20050084987A - Transport format data transmission - Google Patents

Abstract

In a flexible layer one (403) of a GERAN transmitter device, a TFCI, which indicates a particular combination of cyclic redundancy check, channel coding and rate matching, is generated by a TFCI generating process (412) using information from the medium access control layer. The TFCI is coded by a coding process (413), and inserted into the data stream by a TFCI insertion process (414). Each code has more bits than the corresponding TFCI, and identifies uniquely the TFCI. The coded TFCI is spread across the pre-interleaved block with portions placed in fixed positions in each burst. Interleaving is then performed by an interleaver (411). The coded TFCI used with a half-rate channel is the central segment of the coded TFCI used in the corresponding full-rate channel. The additional loss is so small as to be insignificant, but the FER performance is significantly improved, compared to using the full-rate codes, as a result of the increased payload of the content data bits. In half-rate mode, the amount of coded TFCI data gives rise to a ratio of the performance of the coding of the transport format combination data to the performance of the coded content data which is at a similar level to the ratio in the full-rate mode.

Description

Transport format data transmission

The present invention relates to a wireless transmitter device comprising a first adaptable layer and a method of operating a wireless transmitter comprising a first adaptable layer. The invention also relates to a mobile device and a base station transceiver.

In the current GERAN (GSM / EDGE Radio Area Network) Iu mode, the MAC (Intermediate Access Control) layer uses logical channels (traffic or control channels) and basic physical subchannels (dedicated basic physical subchannels or shared basic physical subchannels). It is responsible for the mapping between). Logical channels are channels that the physical layer provides to the MAC layer. The mapping of these logical channels and the underlying physical subchannels are all specified in the GSM / EDGE specification, so that the operation of the MAC layer can be relatively simple.

In UTRAN (UTMS Terrestrial Radio Access Network) a different approach is used, instead of providing logical channels, the physical layer provides transport channels (TrCH, TRansport CHannels) that can be used by the MAC layer. The transport channel can be used to send a flow over the air interface. Many transport channels can be active at the same time and multiplexed at the physical layer. Transport channels are established when establishing a call by the network.

The concept of transport channels is proposed for use in GERAN. Each of these transport channels can carry one flow with a certain quality of service (QoS). Since many transport channels are multiplexed and transmitted on the same dedicated physical subchannel, for example, different protections can be made for different classes of bits. The settings used on the transport channel, i.e. number of bits, coding, interleaving, etc., are represented by transport format combination (TF). As in the UTRAN, several transport format combinations can be associated with one transport channel. For example, in adaptive multirate encoding (AMR), item 1a bits have their own TrCH with one transport format combination set per AMR mode. The setting of transport format combinations can be controlled by the network and signaled to the mobile under call setup. In both mobile and BTS, transport format combinations can be used to configure encoder and decoder units. When constructing a transport format combination, the network can make a choice between several predefined periodic redundancy check (CRC) lengths and code types. For each transport format channel, any number of transport format combinations may be configured under call setup.

The transport blocks TB are arranged to be exchanged between the MAC layer and the physical layer based on a transport time interval (TTI) (eg, 20 ms). One transport format combination is selected for each transport block and is indicated via a transport format combination indicator (TFI). That is, TFI tells which channel coding is used for a particular transport block on a particular TrCH during TTI.

Only some of the transport format combinations of different TrCH are allowed. Valid combinations are called transport format combinations (TFCs). When transport combinations are combined into a TFC, the sum of the output bits is in the radio packet on the base physical subchannel, such as 464 bits for Gaussian minimum shift keying (GMSK) full-rate channels. This is the total number of bits available. The set of valid TFCs on a physical subchannel is called a transport format combination set (TFCS).

To decode the received sequence, the receiver needs to know the active TFC for the radio packet. This information is transmitted through the Transport Format Combination Indicator (TFCI) field. This field is the first layer header and has the same function as the stealing bits currently commonly used. Each TFC in the TFCS is assigned a unique TFCI value, which is the first to be decoded by the receiver upon reception of a radio packet. From the decoded TFCI value, transport format combinations for different transport channels can be found and the decoding can be started.

1A illustrates the proposed structure of a GERAN first adaptable layer. This reflects the structure that has been standardized for UL in UTRAN, but is much simpler.

Referring to FIG. 1A, the physical layer includes the following sequence of processes with respect to each TrCH provided by the second layer: CRC attach, channel coding, radio segment equalization, first interleaving, segmentation. segmentation, rate matching, transport channel multiplexing, TFCI mapping, and second interleaving. In the CRC attach step, error detection is provided for each transport block via the CRC. The size of the CRC to be used is fixed for each TrCH and is configured by a radio resource layer (RRC) higher than the first layer, and is a semi-static attachment of the transport format combination. The entire transport block is used to calculate parity bits. Code blocks are output from the CRC attach process.

The code blocks are then processed by the channel coding process to produce coded blocks. The channel coding to be used is selected by the RRC and can only be changed via higher layer signaling. The channel coding used is a semi-static attachment of the transport format combination, but in practice there is a possibility of being fixed for each TrCH. Thus, for AMR, the same channel coding is used for all modes, and rate matching simply adjusts the code rate by puncturing or repetition. In the radio segment equalization step, the wireless segment size equalization adjusts (by padding padding) the input bit sequence, allowing the coded block to be split into equally sized S _i data segments. The first interleaving is a simple block interleaver with inter-column permutation. Its task is to ensure that no coded consecutive bits are transmitted over the same radio packet.

When the TTI is longer than the radio packet duration, the input bit sequence is divided by the segmentation process, and each S _i radio segment is mapped to one radio packet (S _i = transmission time / radio packet duration). As a result, the input bit sequence is mapped to _Si consecutive radio packets.

The three processes described last (equalization, first interleaving and segmentation) are only used when the TTI is longer than the radio packet duration, otherwise it passes. For each coded block, they generate _Si wireless segments.

The rate matching process is the heart of the first adaptable layer. This causes the bits of the wireless segment on the transport channel to be repeated or punctured. Layers above the first layer assign rate matching attachments for each transport channel. This attachment is semi-static and can only be changed via higher layer signaling. Once the number of bits to be repeated or removed is calculated, rate matching may begin. The higher the attachment value, the more important the bits (more iterations / less puncturing). Since the block size is dynamic attachment, the number of bits on the transport channel can vary between different transmission times. When this happens, the bits are repeated or punctured to make the total bit rate after TrCH multiplexing equal to the total channel bit rate of the assigned dedicated physical channels. The data output from the rate matching process is called a radio frame. For every radio packet to be transmitted, rate matching generates one radio frame per radio segment, such as per TrCH.

In the TrCH multiplexing step, one radio frame from each TrCH is delivered to TrCH multiplexing for every radio packet to be transmitted according to the TFC. These radio frames are serial multiplexed into a coded composite transport channel (CCTrCH). For every radio packet to be transmitted, the TFCI coded at the start of the CCTrCH is appended by the TFCI mapping process before interleaving. The coded TFCI and CCTrCH are interleaved together by a second interleaving step for radio blocks. Interleaving is diagonal or rectangular block and is implemented at call setup.

Another alternative structure is shown in FIG. 1B. Here, the radio segment equalization, first interleaving, and segmentation processes of the FIG. 1A structure are omitted.

1A and 1B illustrate the structure of an alternative physical layer or first adaptation layer, proposed for use in GERAN.

2 illustrates a mobile communication system including components in accordance with the present invention.

3 is a block diagram of a mobile station of the FIG. 1 system.

4 is a block diagram of a base station transceiver of the FIG. 1 system.

Figure 5 illustrates the lower levels of a protocol stack used in an embodiment of the invention.

6 shows the generation of radio signals by the transmitter and the method according to the invention.

According to a first aspect of the present invention, there is provided a wireless transmitter device in which data indicative of a transport format combination is encoded and combined with content data for inclusion in a wireless packet, the device being transported in a wireless packet for a full-rate channel. Operate to include a code selected from the set that includes the format combination data that contains more bits than that transport format combination data and associates it with codes that identify the transport format combination data, wherein the data is at a lower rate in the full-rate channel. In one mode transmitted over the channel of, it operates to include in the wireless packet coded transport format combination data that makes up a fraction of the entire code selected from the set of codes.

According to a second aspect of the invention, there is provided a wireless transmitter device in which data indicative of a transport format combination is encoded and combined with content data for inclusion in a wireless packet, the device being in a wireless packet for a full-rate channel. And a significant amount of coded transport format combination data that derives a specific ratio of coding performance of the transport format combination data to the performance of the encoded content data, wherein the data is transmitted on a lower rate channel than on a full-rate channel. In mode, it operates to include a significant amount of encoded transport format combinations that derive a ratio of coding performance of transport format combination data to performance of coded content data at a level similar to the ratio of full-rate channels.

The transmitter device of the above aspects preferably comprises a first adaptable layer. It will be understood that the term 'first adaptable layer' refers to a physical layer capable of supporting a plurality of active transport channels that can be independently configured simultaneously. An apparatus according to this aspect of the present invention includes an interleaver for interleaving encoded transport format combination data into encoded content data. The wireless transmitter device may be included, for example, in a base station transceiver or in a mobile phone.

According to a third aspect of the present invention, there is provided a method of operation of a wireless transmitter device in which data indicative of a transport format combination is encoded and combined with content data for inclusion in a wireless packet, the method comprising: wireless for a full-rate channel In the packet, comprising a code selected from the set comprising transport format combination data comprising more bits than the corresponding transport format combination data and associated with codes identifying the transport format combination data, and wherein the data is a full-rate channel. In a mode transmitted over a channel of lower rate in the step of including, in the radio packet, coded transport format combination data constituting less than one whole code selected from the set of codes.

According to a fourth aspect of the invention, there is provided a method of operation of a wireless transmitter device in which data representing a transport format combination is encoded and combined with content data for inclusion in a wireless packet, the method comprising: In a wireless packet for including a significant amount of encoded transport format combination data that derives a specific ratio of coding performance of the transport format combination data to the performance of the encoded content data, and wherein the data is at a lower rate than in a full-rate channel. In a mode transmitted on a channel, comprising a significant amount of encoded transport format combinations that derive a ratio of the coding performance of the transport format combination data to the performance of the encoded content data at a level similar to that of the full-rate channel. .

The ratios are substantially the same.

An advantage of the above aspects of the present invention is that more content data per wireless packet can be transmitted on channels of lower than full-rate rates without any significant reduction in transmission reliability when compared to the prior art.

In any of the above aspects of the invention, the coded transport format combination data in the lower rate mode is a number of bits of the full rate code multiplied by the ratio of the bit rate of the lower rate channel to the full rate channel. And may contain the same or substantially the same number of bits as. In addition, the transport format combination data encoded for the lower rate channel may form a central segment of code selected from the set. This specification is particularly useful when codes with certain suitable characteristics are used because this specification can provide a good balance between the forces of transport format combination data decoding and the amount of content data that can be transmitted. Codes proposed for use in GERAN TFCIs are particularly suitable.

The present invention includes a specific application for GERAN, in Iu mode and other modes. However, the present invention is more widely applicable than the GERAN application described in the embodiments.

Preferred embodiments of the invention will be described below by way of example only with reference to the accompanying drawings.

Referring to FIG. 2, the mobile telephone network 1 has a plurality of switching centers comprising first and second switching centers 2a, 2b. The first switching center 2a is connected with a plurality of base station controllers including first and second base station controllers 3a and 3b. The second switching center 2b is likewise connected with a plurality of base station controllers (not shown).

The first base station controller 3a is connected to and controls the base station transceiver 4 and a plurality of other base station transceivers. The second base station controller 3b is likewise connected to and controls a plurality of base station controllers (not shown).

In this example, each base station transceiver serves its own cell. Thus, the base station transceiver 4 services the cell 5. Alternatively, a plurality of cells may be serviced by using a directional antenna by one base station transceiver. A plurality of mobile stations 6a, 6b are located in the cell 5. The number and identity of mobile stations in any given cell changes over time.

The mobile telephone network 1 is connected to the public switched telephone network 7 by a gateway switching center 8.

The packet service side of the network includes a plurality of packet service support nodes (only one shown) 9 connected to each of the plurality of base station controllers 3a and 3b. At least one packet service support gateway node 10 connects the or each packet service support node 10 with the Internet 11.

The switching centers 3a and 3b and the packet service support nodes 9 access the home location register 12.

The communication between the mobile stations 6a, 6b and the base station transceiver 4 employs a time division multiplexed access (TDMA) scheme.

Referring to FIG. 3, the first mobile station 6a includes an antenna 101, an rf subsystem 102, a baseband DSP (digital signal processing) subsystem 103, an analog audio subsystem 104, a loudspeaker ( 105, a microphone 106, a controller 107, a liquid crystal display 108, a keypad 109, a memory 110, a battery 111, and a power supply circuit 112.

The rf subsystem 102 includes if and rf circuits of the transceiver of the mobile telephone and a frequency synthesizer for tuning the transceiver of the mobile station. Antenna 101 is coupled to rf subsystem 102 for transmitting and receiving wireless waves.

Baseband DSP subsystem 103 is coupled with rf subsystem 102 that receives baseband signals from that subsystem and transmits baseband modulated signals to that subsystem. Baseband DSP subsystem 103 includes codec functions that are well known in the art.

Analog audio subsystem 104 is coupled to and receives demodulated audio from baseband DSP subsystem 103. Analog audio subsystem 104 amplifies the demodulated audio and feeds it to loudspeaker 105. The acoustic signals detected by the microphone 106 are preamplified by the analog audio subsystem 104 and sent to the baseband DSP subsystem 4 for coding.

The controller 107 controls the operation of the mobile phone. The controller is connected to an rf subsystem 102 that supplies tuning commands to the frequency synthesizer and also to a baseband DSP subsystem 103 that supplies control data and management data for transmission. The controller 107 is operated by a program stored in the memory 110. The memory 110 is shown as separate from the controller 107, but may be combined with the controller 107.

The display device 108 is connected with a controller 107 to receive control data, and the keypad 109 is connected with a controller 107 to supply user input data signals to the controller.

The battery 111 is connected with a power supply circuit 112 that provides regular power of various voltages used by the components of the mobile telephone.

The controller 107 is programmed to control a mobile station including application programs that perform voice and data communication and utilize data communication functions of the mobile station, such as a WAP browser.

The second mobile station 6b is similarly configured.

Referring to FIG. 4, a very simplified base station transceiver 4 includes an antenna 201, an rf subsystem 202, a baseband DSP (digital signal processing) subsystem 203, a base station controller interface 204, and a controller. (207).

The rf subsystem 202 includes if and rf circuits of the base station transceiver transceiver and a frequency synthesizer for tuning the transceiver of the base station transceiver. Antenna 201 is coupled to rf subsystem 202 for transmitting and receiving wireless waves.

Baseband DSP subsystem 203 is coupled to rf subsystem 202 that receives baseband signals from this subsystem and transmits baseband modulated signals to that subsystem. Baseband DSP subsystem 203 includes codec functions that are well known in the art.

The base station controller interface 204 interfaces the base station transceiver with the base station controller 3a that controls it.

The controller 207 controls the operation of the base station transceiver 4. The controller is coupled with an rf subsystem 202 that supplies tuning commands to the frequency synthesizer and a baseband DSP subsystem that supplies control and management data for transmission. The controller 207 operates in accordance with a program stored in the memory 210.

When used for circuit switched voice traffic, the channelisation scheme is the same as used in GSM.

The baseband DSP subsystems 103, 203 and the controllers 107, 207 of the mobile stations 6a, 6b and the base station transceiver 4 are configured to implement two protocol stacks. The first protocol stack is for circuit switched traffic and is substantially the same as used in conventional GSM systems. The second protocol stack is for packet switched traffic.

Referring to FIG. 5, the layers associated with the radio link between the mobile stations 6a, 6b and the base station controller 4 include a radio link control (RLC) layer 401, an intermediate access control (MAC) layer 402, and Physical layer or first adaptable layer (FLO) 403. Other layers exist above the illustrated layers, but are not shown for clarity.

The radio link control layer 401 includes two modes, pass through and pass through mode. In transparent mode, the data is not modulated and just passes up or down the radio link control layer.

In non-passing mode, the radio link control layer 401 builds data blocks in data units received from higher levels by providing link adaptability and, if necessary, segmenting or concatenating data units, and stacking them. The reverse process is performed for data going upstream. This layer is responsible for detecting lost data blocks or reordering the data blocks for the upward transmission of their contents, depending on whether the approved mode is being used. This layer may also provide backward error correction in the approved mode.

The intermediate access control layer 402 is responsible for assigning data blocks from the radio link control layer 401 to the appropriate transport channels and sending the received radio packets from the transport channels to the radio link control layer 401.

The physical layer 403 generates the transmitted radio signals from the data passing through the transport channels and sends the received data through the correct transport channel to the intermediate access control layer 402. The physical layer 403 includes the structure shown in FIG.

Referring to FIG. 6, data generated by applications 404a, 404b, 404c is propagated down the protocol stack to physical layer 403a, 403b. The physical layer 403a, 403b carries data from the applications 404a, 404b, 404c through different transport channels 405, 406, 407 depending on the type of data. Each transport channel 405, 406, 407 may be configured to process signals in accordance with a plurality of processing schemes 405a, 405b, 405c, 406a, 406b, 406c, 407a, 407b, 407c. The configuration of the transport channels 405, 406, 407 is established during call setup based on the performance of the mobile station 6a, 6b and the network and the characteristics of the application or applications 404a, 404b, 404c in operation.

Processing schemes 405a, 405b, 405c, 406a, 406b, 406c, 407a, 407b, 407c include periodic redundancy checks 405a, 406a, 407a, channel coding 405b, 406b, 407b, and rate matching 405c, Unique combinations of 406c, 407c. These unique processing schemes are the TFCs mentioned above. Other processing steps shown in the physical layer of FIG. 1 have been deleted in FIG. 6 for simplicity. Steps 405d, 406d, 407d are optional interleaving steps deleted from FIG.

The synthetic data rate generated for the transport channels 405, 406, 407 should not exceed the data rate of the physical channel or channels assigned to the mobile stations 6a, 6b. This places a limit on the transport format combinations that can be tolerated. For example, when there are three transport formats TF1, TF2, and TF3 for each transport channel, the following combinations may be valid and thus constitute TFCIs:

TF1 TF1 TF2

TF1 TF3 TF3

However, the following combinations will not be valid and therefore TFCIs cannot be configured.

TF1 TF2 TF2

TF1 TF1 TF3

The data output by the transport channel interleaving processes is multiplexed by the multiplexing process 410 and then experiences additional interleaving 411.

The TFCI is generated by the TFCI generation process 412 from the information in the intermediate access control layer and encoded by the coding process 413. The encoded TFCI is appended to the beginning of the data stream by the TFCI insertion process. Interleaving is then performed by the interleaver 411. Since the encoded TFCI does not experience variable interleaving, it can be easily located by the receiving station. Accordingly, the receiver may deinterleave (deinterleave) the signal, identify and decode the encoded TFCI, and separate and decode the transport channels using the decoded TFCI.

The proposed TFCI codes for GMSK full rate channels are: 1 bit TFCI encoded in 8 bits, 2 bit TFCI encoded in 16 bits, 3 bit TFCI encoded in 24 bits, 4 bit TFCI encoded in 28 bits, and 5 bit encoded in 36 bits. TFCI. Each TFCI is associated with a code in a one-to-one relationship, as shown in Tables 2-6 below. This is code distributed before interleaving (also known as signed TFCI). The code is selected from the code group shown in the tables. As can be seen, each code contains more bits than that TFCI, and uniquely identifies the TFCI.

A significant amount of encoded transport format combination data (encoded TFCI) results in a specific ratio of coding performance of the transport format combination data to that of the encoded content data. The ratio is preferably greater than 1 (unity), since this means that the coding used to encode the TFCI is more powerful than the coding used to encode the content data. The ratio of coded TFCI data performance to coded content data performance derived from this arrangement can be measured using any suitable simulator. The performance can be measured in terms of block error rate and frame erase rate. It is desirable that the frame deletion rate including TFCI errors is not more than 1 dB greater than the frame deletion rate without TFCI. It is desirable that the frame drop rate is not greater than 0.5 dB, which is greater than without TFCI. A performance reduction of 0.5 dB may be considered acceptable in view of the extra data content that can be transmitted over the channel.

Half-rate (HR) channels are allowed by the first adaptable layer 403. For a certain amount of content data, the coding rate is half or almost half the intensity of the coding rate of the full rate channels (eg 0.52 or 0.48 times the intensity).

The inventors of the present invention performed the test with a half-rate channel using a data packet size of 100 bits, which derives a 5 kbit / s channel with a block transmission interval of 20 ms. In this test, each block of data was processed with a six-bit CRC, and a 1/3 rate mothercode used with a carrier frequency of 900 MHz. The coded TFCI was inserted before interleaving the data using diagonal interleaving over four bursts. The result of this interleaving was the placement of the bits of the encoded TFCI, reordered through four packets, using the even positions of the first two blocks and the odd positions of the last two blocks. Testing was performed for each of the possible coded TFCI lengths, and each test involved processing of 20.000 blocks. The test results are summarized in Table 1. Here, two kinds of frame erasure rates (FEFs) are compared, in which FER is evaluated using a CRC for the data block, and in one, errors from TFCI that are incorrectly decoded are included. The link level performance was evaluated through simulations on TU3iFH when feeding these codes into a clean FLO half-rate channel.

The rightmost column of Table 1 shows the dB of loss resulting from erroneously decoded TFCIs. As shown in the table, there is no loss for any code rates, so the performance is considered satisfactory. However, when looking at the TFCI error rate compared to FER, a performance difference of about 8 dB is seen and observed in all codes. This indicates that the efficient code rate of TFCI is much higher than the code rate of the data block. The present invention stems in part from this observation. By reducing the coding for TFCI, the bits of the half-rate channel can be free for content data.

According to the invention, the codewords used for full-rate channels are reduced in length by the factor of two, shorter codes applied to the half-rate channels. In addition, the coded transport format combination data used for half-rate channels is part of the corresponding coded TFCI used for full-rate channels. The inventors found that using the middle segment of each codeword yields the best performance because of the nature of the codes. The code provided for interleaving is provided by the coding process 413 based on the channel rate and the TF information.

The codes used for half-rate channels are illustrated in 6 in Table 2 below. In these tables, the TFCI is given in the leftmost column, the coded TFCI for full-rate channels is given in the rightmost column, and has bits used for half-rate channels making up the middle segment of full-rate codes. The codewords of the 1 bit TFCI consist of 3 to 6 bits of full-rate GMSK codewords, as shown in FIG.

For a 2-bit long TFCI for full-rate channels, bits 5 through 12 are used for half-rate channels as shown in Table 3:

For a 3-bit long TFCI for full-rate channels, bits 7 through 18 are used for half-rate channels as shown in Table 4:

For a 4-bit long TFCI for full-rate channels, bits 8 through 21 are used for half-rate channels, as shown in Table 5:

For a 5-bit long TFCI for full-rate channels, bits 10 through 27 are used for half-rate channels:

The performance when using these codes was previously evaluated by testing using the same assumptions given above. The link level results are summarized in Table 7 below.

When using the middle segment of the full-rate code for the half-rate channel it can be seen that the additional loss is not so small, which means that the reduced coding of the TFCI does not imply additional loss of frames. As a result of the increased payload of the content data bits, the FER performance is improved compared to when using full-rate codes. FER is improved by 0.5 dB for 1 bit TFCIs, 0.1 dB for 2 bit TFCIs, 0.6 dB for 3 bit TFCIs, 0.6 dB for 4 bit TFCIs, and 5 bit TFCIs. Is improved by 1.2dB. The amount of coded TFCI data results in a ratio of coding performance of transport format combination data to coded content data performance, at a level comparable to that in full-rate mode.

In summary, the radio packet contains coded transport format combination data that constitutes less than all of one code selected from the code group used for the full-rate channels. Each reduced code consists of a segment that is half the code length used for full-rate channels and is taken from the middle of the associated code.

Although the embodiment of the present invention uses GMSK channels, the present invention can also be applied to signals modulated using other modulation techniques such as 8PSK. Also, performance may vary if different codes are used, but other codes may be used to represent transport format combination data. Channels in which shorter codes are used may be quarter rate channels, or any other suitable rate channel. The amount of code that needs to be taken to provide an acceptable level of performance depends on the nature of the codes and the bit rate ratio of that channel to the bit rate of the full-rate channel.

Claims (11)

A wireless transmitter apparatus in which data representing a transport format combination is encoded and combined with content data for inclusion in a wireless packet, In a wireless packet for a full-rate channel, operate to include a code selected from the set comprising transport format combination data comprising more bits than that transport format combination data and associating with codes identifying the transport format combination data; In a mode in which data is transmitted on any channel at a lower rate than in a full-rate channel, operating in a radio packet to include coded transport format combination data comprising less than one portion of the entire code selected from the code set. Device characterized in that. The method of claim 1, And a first adaptable layer (403). 3. The method of claim 1 or 2, wherein in the lower rate mode, the encoded transport format combination data is equal to the number of bits of the full-rate code multiplied by the ratio of the bit rate of the lower rate channel to the full rate channel. And the same or substantially the same number of bits. 4. The apparatus according to any one of claims 1 to 3, wherein the coded transport format combination data for the lower rate channel constitutes a central segment of code selected from the set. A radio transmitter device in which data representing a transport format combination is encoded and combined with content data for inclusion in a radio packet, In a wireless packet for a full-rate channel, it operates to include a significant amount of coded transport format combination data that derives a certain ratio of coding performance of the transport format combination data to the performance of the encoded content data, the data being a full-rate channel. In a mode transmitted on a channel at a lower rate than on, a significant amount of encoded transport format combination data that derives a ratio of the coding performance of the transport format combination data to the performance of the encoded content data at a level comparable to that of the full-rate channel. Apparatus for operating to include. The method of claim 5, And a first adaptable layer (403). The method according to any one of claims 1 to 6, And an interleaver (411) for interleaving (inserting) the encoded transport format combination data in the encoded content data. A mobile telephone comprising a wireless transmitter device as claimed in any of the preceding claims. A base station transceiver comprising a radio transmitter device as claimed in any of claims 1-8. A method of operating a wireless transmitter device in which data representing a transport format combination is encoded and combined with content data for inclusion in a wireless packet, In a wireless packet for a full-rate channel, comprising: a code selected from a set comprising transport format combination data comprising more bits than the transport format combination data and associating with codes identifying the transport format combination data; And In a mode in which data is transmitted over a lower rate channel than in a full-rate channel, comprising, in a wireless packet, coded transport format combination data comprising less than one portion of the entire code selected from the set of codes; Characterized in that. A method of operating a wireless transmitter device in which data representing a transport format combination is encoded and combined with content data for inclusion in a wireless packet, Including, in a radio packet for a full-rate channel, a significant amount of encoded transport format combination data that derives a specific ratio of the coding performance of the transport format combination data to the performance of the encoded content data; And In a mode where data is transmitted on a lower rate channel than on a full-rate channel, a significant amount of encoding derives the ratio of the coding performance of the transport format combination data to the performance of the encoded content data at a level comparable to that of the full-rate channel. And including the combined transport format combination.