MXPA00010714A - Method and system for multiplexing of multiple users for enhanced capacity radiocommunications - Google Patents

Abstract

A radiocommunication system supports multi-user multiplexing. Half-rate data communications with interleaving of data between two sources are described. This multiplexing technique provides, effectively, two sub-channels of information, which in turn provides an opportunity to improve decoding/demodulation of each sub-channel by re-encoding/remodulation information after successful decoding/demodulation of one sub-channel.

Description

METHOD AND SYSTEM FOR MULTIPLE PURPOSES OF MULTIPLE USERS FOR IMPROVED RADIO COMMUNICATIONS CAPACITY BACKGROUND Applicant's invention relates to electrical communication, and more particularly to wireless communication systems such as cellular and satellite radio systems, for various modes of operation (analogue, digital, dual mode, etc.), and access techniques such as multiple access with frequency division (FDMA = Multiple Access Division Frequency), multiple access with time division (TDMA = Time Divisional Multiple Access), multiple access with code division (CDMA = Code Divisional Multiple Access), hybrid FDMA / TDMA / CDMA, for example. More specifically, this invention relates to methods and systems that detect multiple streams of information that are transmitted as a composite signal in a manner intended to improve detection of individual streams. In North America, digital and multiple communication access techniques such as TDMA are currently provided by a digital cellular phone radio system called the advanced mobile telephony service 1 < digital (D-AMPS = Digital Advanced Mobile Phone Service), some of the characteristics of which are specified in the provisional standard TIA / EIA / IS-54-B, "Dual-Mode Mobile Station-Base Station Compatibility Standard". Compatibility of Base Station-Dual Mode Mobile Station) published by the Association of Telecommunications Industries and Electronic Industries Association (TIA / EIA = Telecommunications Industry Association and Electronic Industries Association), and some of which are specified by the subsequent provisional standard IS-136 (which describes, among other things, a digital> control channel), these standards are expressly incorporated herein by reference. Due to the large existing consumer equipment base operating only in the frequency division multiple access (FDMA) analog domain, TIA / EIA / IS-54-B is a dual mode (analogue and digital) standard, which allows analog compatibility together with digital communication capability. In a TDMA cellular radiotelephone system, each radio channel is divided into a series of time slots, i each of which contains a burst of information from a data source, for example a digitally coded portion of a speech conversation . The time slots are grouped into successive TDMA frames, which have a predetermined duration. The number of time slots in each TDMA frame is related to the number of different users that can simultaneously share the radio channel. If each slot in a TDMA box is assigned * _ to a different user, the duration of a TDMA frame is the minimum amount of time between successive time slots assigned to the same user. The successive time slots assigned to the same user, which are usually nb consecutive time slots in the radio bearer, constitute the user's digital traffic channel (DTC), which can be considered as an assigned logical channel. to user. If only one of the many possible modalities of a TDMA system as described above, the standards TIA / EIA / IS-54-B, IS-136 provide or provide that each TDMA frame consists of six consecutive time slots and has a duration of 40 milliseconds (msec) as illustrated in Figure 1. In this way , each radio channel can carry from three to six DTCs (for example three to six telephone conversations). Depending on the source speeds of speech coders / decoders (codees) used to digitally encode conversations. These speech codes can operate either at full speed or at medium speed. A full-speed DTC requires twice as many time slots in a given period of time as a half-speed DTC, and in TIA / EIA / IS-54-B and IS-136, each full-speed DTC uses two slots of each TDMA frame, ie the first ** and fourth, second and fifth or third and sixth of six slots in a TDMA frame. Each medium speed DTC uses a time slot of each TDMA frame. During each DTC time slot, as seen in Figure 2, 324 bits are transmitted, of which the main portion, 260 bits, is due to the codec's »speech output, including bits due to error correction coding of the speech output and the reatant bits are used for protection times and general signaling for purposes such as synchronization. Once the information has been sent out from the speech code, it is then processed for transmission on a radio bearer. This processing can be generalized as illustrated in the upper branch of Figure 3. There, channel coding 30 and interleaving 32 are provided to protect against channel errors that corrupt the information as it is transmitted over radio channel 36. Channel coding, for example block coding or convolutional coding, adds redundancy to the information stream that can be used to identify and correct errors that occur during transmission of information about the radio channel. Bit errors that occur due to transmission over the radio channel often occur in bursts. However, certain types of ttt channel coding are more effective in correcting single-bit errors and are less effective in correcting long strings of erroneously received bits. In agreement, the interleaving is used to separate consecutive bits of information and transmit them in a non-consecutive way. In this way, burst errors are effectively dispersed in such a way that when the received information is deinterleaved, the coding of c nal is more likely to be able to correct the errors that occur during transmission. Different systems use different types of channel coding and interleaving. For example, systems designed in accordance with the system of the IS-136 standard described above, can allow channel coding and interleaving according to a vocoder described herein, as illustrated in Figure 4. There, the speech encoder output 40 is separated into class 1 and class 2 bits, class bits, - 1 are more important than class 2 bits in terms of signal quality perceived before reproduction, and therefore are more strongly protected against errors . In fact, to further protect the 12 most perceptually significant bits of class 1, a 7-bit cyclic redundancy check (CRC = Cyclic Redundancy Check) is calculated on those 12 bits in block 42 and added to the bit string to be encoded convolutionally in block 44. In convolutional coding, an encoded bit of output not only depends on the bit value of the most recently bit > fed, the preceding bit values are provided in a form of memory that can be used to detect errors in the received signal stream. The convolutional coding rate, in this example 1/2, denotes the amount of redundancy that is provided-in this case, for each bit of information fed, two coded bits are produced. The encoded bits of class 1 and the uncoded bits of class 2 are then encrypted (block 46) and interleaved (block 48) on two time slots, as illustrated in Figure 5. In this way, the bits of each of the two speech frames, are transmitted in each «Go time slot of the D-AMPS systems to disperse burst errors as described above. Returning to Figure 3, the output of the interleaver 32 is sent to the modulator 34, where the data is modulated in the radio frequency carrier. In the D-AMPS example described above, the particular modulation currently employed is shifted p / 4 with > encryption with differentially encoded quadrature phase shift (DQPSK = Differentially Encoded Quadrature Phase Shift Keying). In this scheme, as will be appreciated by those skilled in the art, the modulation of * _ Information is achieved by relative changes in phase of the modulation waveform. The Gray or binary mirrored encoding is used in constellation mapping (described below) of di-bit symbols in such a way that adjacent signal changes only differ by one bit. In this way, interference errors that result in erroneous selection of a symbol associated with an adjacent phase, only create a single bit error. Once your information is modulated, some post-processing can be returned (for example, filtering and expansion) and the information is then transmitted over the radio channel. To complete, Figure 3 also indicates functional blocks associated with a receiver, for example in a mobile station, which processes the received signal. There, the desmoddler 38, deinterleaver 41 and decoder 43 > they effectively reverse the processes performed by the modulator 34, interleaver 32 and channel encoder 30, respectively. Those with skill in the specialty will be familiar with the operation of these devices and, therefore, are not described further here. An optional equalizer 39 (or RAKE receiver, for example for a DS-CDMA system) can also be included in the signal processing path. This device handles the effects of signal reflections that occur during transmission of * the information about the radio channel, for example when creating a model of the channel? and attempt the determination of the most likely transmitted sequence, in view of the various echoes received during a reception interval. As previously mentioned, the information in IS-136, as well as many other systems, can be transmitted at full speed or half speed. Medium speed communications provide an opportunity for additional capacity in terms of the number of connections, since each frame supports, for example, six channels instead of three. However, the interleaving of two slots described above is applicable only to full-speed transmissions, since half-speed transmissions use only one time slot per frame. In this way, current implementations of medium speed communications in IS-136 systems, do not allow interleaving inter-slots and in accordance with this, have problems of error correction burst. Accordingly, it would be convenient to identify solutions to provide medium speed communications that overcome these problems and disadvantages. More generally, it would be convenient to provide systems and methods that consider multi-user detection, where multiple users or sources transmit information in an interleaved or overlapping manner. COMPENDIUM These and other disadvantages and limitations of conventional methods and systems for communicating information are overcome in accordance with the present invention, wherein applicants present techniques and systems for multiplying two users or sources in each time slot at medium speed. This trunking technique effectively provides two sub-channels of information which in turn provide an opportunity to improve the decoding / demodulation of each sub-channel by re-encoding / re-modulating information after successful decoding / demodulation of a sub-channel. channel. Various modulation constellations are described that take advantage of the fact. { that certain bits in each symbol can be known. BRIEF DESCRIPTION OF THE DRAWINGS These and other objects, features and advantages of the present invention will be more apparent upon reading the following detailed description, which is taken in conjunction with the accompanying drawings, wherein: Figure 1 illustrates an exemplary chart format in a conventional IS-136 system; Figure 2 illustrates both an uplink (top) and top down (bottom) time slot format for a conventional IStl36 system; or Figure 3 is a functional block diagram of an exemplary conventional radio communication system; Figure 4 illustrates channel coding and interleaving according to a conventional IS-136 system; Figure 5 illustrates interleaving of two slots for integral speed communications in a conventional IS-136 system; Figure 6 is a block diagram of an exemplary mobile station and base station in a radio communication system; Figure 7 illustrates medium speed communication involving sub-channels from two users or sources in accordance with exemplary embodiments of the present invention; Figure 8 illustrates an example symbol embodiment of the present invention; Figure 9 illustrates an exemplary intersymbolic embodiment of the present invention; tt Figures 10-14 (a) illustrate various constellation mappings associated with 8-PSK modulation; Figure 15 illustrates speech interleaving and FACCH and channel coding, in accordance with an exemplary embodiment of the present invention; Y tt Figures 16 (a) and 16 (b) illustrate exemplary downlink formats for 8-PSK and 8-DPSK modulated transmissions, respectively. DETAILED DESCRIPTION The following exemplary embodiments are provided in the context of TDMA radio communications systems. However, those skilled in the art will appreciate that this access methodology is simply used for the purposes of illustration and that the present invention easily applies to various different types of access methodologies, including for example, multiple access with code division (CDMA / TDMA) hybrid tt. Figure 6 is a block diagram of an exemplary cellular mobile radiotelephone system, wherein the present invention can be implemented, including an exemplary base station 110 and mobile station 120. The base station includes a control and processing unit 130 which is connected to the MSC 140 which in turn connects to the PSTN (not shown). General aspects of these cellular radiotelephone systems are known in the art, as described by the patent applications of the U.S.A. previously cited and by the US patent. Do not. ,175,867 granted to Wejke et al., Entitled "Neighbor-Assisted Handoff in a Cellular Communication System", and the patent application of the U.S.A. No. 07 / 967,027 entitled "Multi-mode Signal Processing", which will be presented on October 27, 1992, both of which are incorporated herein by reference in this application. The Toase station 110 handles a plurality of voice channels through a voice channel transceiver 150, which is controlled by the control and processing unit 130. Also, each base station includes a control channel transceiver 160 which can be able to handle more than one control channel. The control channel transceiver 160 is controlled by the processing and control unit 130. The control channel transceiver 160 broadcasts control information on the control channel of the base station or cell to mobile interlocked in that control channel. It will be understood that transceivers 150 and 160 can be implemented with a single device, such as voice and control transceiver 170, for use with DCCs and DTCs that share the same radio carrier frequency. The mobile station 120 receives the information broadcast in a control channel in its control and voice channel transceiver 170. Then, the processing unit 180 evaluates the received control channel information, which includes the characteristics of cells that are candidates to interlock with the mobile station, and determine in which cell the mobile will lock. Advantageously, the received control channel information not only includes absolute information regarding the cell with which it is associated but also contains relative information referring to other cells next to the cells in which the control channel is associated., as described in U.S. Pat. No. 5,353, 332, - granted to Raith et al, entitled "Method and Apparatus for Communication Control in a Radiotelephone System ^ (Method and Apparatus for Control Communication in a Radiotelephone System), which is incorporated herein in this application by As previously mentioned, full-speed communications in exemplary IS-136 systems allow interleaving information of a user or source over each time slot assigned to this user (ie, two for IS-136) within each TDMA frame as is illustrated in Figure 5. To extrapolate this type of interleaving to medium speed communications as defined for IS-136 systems, ie each average speed user has only one time slot per frame, I would suggest that the information transmitted at speed media is interspersed over time slots of different TDMA frames, however, interleaving information about time slots of different TDMA for communication of average speed tt contributes with an additional delay in the reproduction of the signal for medium speed communications as opposed to full speed communications. Accordingly, it would be convenient to provide some form of interleaving for medium speed communications to disperse burst errors that occur during the transmission of information, for example between the mobile station 120 and the base station 110 without increased delay. According to exemplary embodiments of the present invention, therefore, interleaving information can be provided for average speed source users, between time slots of the same frame by interleaving information from different users in each time slot in the downlink. This provides the same interleaving delay in the receiver as full speed communication. Consider the exemplary downlink box format in Figure 7 to illustrate this concept. There, the information associated with portions of speech frames XA and YA for user A and portions of speech frames X8 and YB for user B are multiplied together and transmitted in time slot 1. Portions of the frames of speaks YA and ZA for user A and portions of speech frames Y8 and ZB are multiplied together and transmitted in time slot 4.

Similar multiplier information from other users can be done in time slots 2 and 5, y and 6, so that six medium speed channels are still provided in each TDMA box. By dispersing the average speed information of both users A and B through time slots 1 and 4, burst errors are more easily corrected. While this type of interleaving according to the present invention can be provided in the downlink, it is not feasible for the uplink (mobile-to-base address) due to the impossibility of synchronizing transmitter transmissions not geographically co-located associated with the various mobile stations. Despite the fact that the uplink does not lead to this type of interleaving, the mobile stations must be provided with some type of information regarding which uplink time slot they must transmit their data. Consider that conventional average speed communications provide a downlink time slot for each mobile station and therefore, each mobile station simply transmits its uplink burst in a corresponding time slot. However, since according to the present invention, each mobile station can now receive the information of average speed in two f time slots in each frame, the mobile stations must implicitly or explicitly recognize their assigned uplink time slot. An example of an explicit uplink time slot assignment is provided below in a discussion of mode signaling. There are several ways in which the information associated with users A and B can be interleaved within each time slot. For example, the interleaving can be done on a symbol-by-symbol basis, this type of information is referred to as "symbol fold". Symbol bending can take many forms, however in general, bits associated with the user information stream A are assigned to be carried by one or more symbols, followed by bits associated with the information stream of user B assigned to one or more. more symbols in some repetition pattern. Symbol bending can take the form of each sated symbol having bits only associated with a user's information stream, two symbols at a time have bits of information only associated with a user's bitstream (as illustrated) in Figure 8) or any desired pattern. Symbol bending can have varying repetition patterns, for example AABABBAABABB, etc., provided that the pattern was known a priori for all remote units. The data interleaving of two different users in each time slot can also be performed on a bit-by-bit basis in vé of a symbol-by-symbol base. This can also be achieved in accordance with exemplary embodiments of the present invention by assigning one or more bits associated with a user information stream A to a symbol and filling the remaining positions in the symbol with one or more bits of the information stream of the user. user B. An example of this type of multi-symbolized inter-symbols is illustrated in Figure 9. There, a portion of a time slot is illustrated where three-bit symbols are used to transmit information. In this manner, the first symbol has two information bits of the user information stream A and one information bit of the information stream of user B, while the second symbol has two bits of the information stream of user B and a bit of user information A. As the previous mode that uses symbol swapping to provide a mechanism for collating the data of two different users into two slots of different types in a frame, inter-symbol rolling may also be used to distribute data associated with each user through ft 18 of time slots spaced in a frame to protect against burst errors in medium speed communications. Those with skill in the art will appreciate that multiplying bits from different users in a time slot effectively creates two sub-channels "within each time slot. In addition to assigning these sub-channels to different users, it should be appreciated that these sub-channels can also be assigned to different connections associated with a user. For example, information of both a voice connection and a data connection associated with a user, can be transmitted at medium speed by interleaving information of each connection over multiple time slots in a frame, using either the techniques of symbol blinking. or the multi-symbol technique of inter-symbols described above. Likewise, two voice connections or two data connections of a user can be transmitted in a similar manner. Since the preceding exemplary embodiments are based on information associated with two data sources, for example users, to be multiplied over each time slot, a doubt arises as to how to handle the case when only one active user is transmitted by a base station . There are different solutions. First, this active user can be switched to a full speed format (including the use of a full speed vocoder). Of course, the mobile station will have to be informed of the switchover, which is essentially equivalent to a full-speed half-speed communications transfer. This information can be passed to the mobile station using the signaling in the manner described below. Secondly, the concept of two subchannels described above can be replaced in this case by using the same vocoder as for the two subchannel approach but applying more channel coding to fill the bits normally ft supplied by the second source. channel . A third solution is to keep the two sub-channels and send arbitrary or predefined data as the non-existent information "user B". In this way, the existing predefined medium and vocoder channel coding structure can be used even when only an active user receives information in a channel. of >; half speed downlink. Another possibility is to maintain the channel coding structure, but ft eliminate the vocoder and replace predefined data where the coded speech bits would normally occur.

Still another option is to eliminate the channel coding and the vocoder and simply fill the information stream of user B with predefined bits. Finally, the second sub-channel can be filled by repeating each information frame transmitted by an active user, ie copying the speech frames of the active user in the second sub-channel. . The multiplexing of information from multiple users described in the above exemplary embodiments, can be used to provide interleaving and reduce the effects of bursts in medium speed radiocommunications. However, multiplexing of multiple users also allows the opportunity of detection of multiple users, ie using the decoded information of one sub-channel to aid in the decoding of information in another sub-channel. This aspect of the present invention will now be described. The multiple of symbols and multiple intersymbols described above can also be used to provide additional filling to the decoding / demodulation process. In general, since two channels are multiplexed together in a time slot and a radio channel that is subjected to fading and interference, it is likely that at least one of the two sub-channels can be decoupled correctly. For example, user A's mobile station will receive, and will attempt to decode / demodulate * the information in its assigned time slots within each frame. User A may be able to successfully decode his own information, after which no further processing will be required. However, if user A is unable to decode his own information, for example due to CRC failures, then he may try to decode user data B that has been bent with user information A. t If user B can decode / successfully demodulate, then the entire burst can be re-encoded and redispersed and the user A's computer can take a second step when trying to decode its information using the known symbols and / or bits of the user's information B. A process to use the symbols of known information within a stream of information to aid in the process of decoding / demodulating unknown symbols per se, has been described in the prior literature and is therefore not described in detail here. The unstructured reader, however, is directed to U.S. Pat. No. 5,673,291, entitled "Simultaneous Desmodulation and Decoding of a Digitally Modulated Radio Signal Using Known Symbols" (Simultaneous Demodulation and Decoding of a Digitally Modulated Radio Sign Using Known Symbols) and Issued on September 30, 1997 and International Patent Publication No. WO 98/04047 with title "Method and ft Apparatus for Detecting Communication Signal Having Unequal Error Protection "(Method and Apparatus for Detecting Communication Signals that have Unequal Error Protection), and published on January 29, 1998, the description of each of which is hereby incorporated by reference. In the context of symbol bending, for example as illustrated in Figure 8, this process of decoding / demodulation of one sub-channel and then re-encoding / re-modulation and decoding / demodulation of the other sub-channel is direct. The user A will first de-interleave and attempt to decode / demodulate the symbols "A." If successful, the process terminates, otherwise the user A's computer will attempt to decode the de-interleaved sub-channel including the "B" symbols. succeed, the symbols are re-encoded and remodulated, and the user A's computer tries to decode / demodulate the 'A' symbols using the knowledge of the symbols' B1. n the context of multiple inter-symbols, for example as illustrated in Figure 9, determining the 'B' bits in the user equipment A before determining the 'A' bits, can increase the certainty associated with demodulating the 'A' bits. The exemplary intersymbol multiplex illustrated in Figure 9 illustrates three bits per symbol. An exemplary modulation using three bits per symbol is 8-PSK, which has eight constellation points as seen in Figure 10. The transmitter adjusts the quadrature and phase signals corresponding to one of the constellation points. The circle radius represents the signal amplitude. At the receiver, signal quality and noise reduction at the time of the decision of the symbol will generate a received signal that is different than any of the eight specified constellation points.

The more interference is associated with the radio channel, the more distance will separate the current constellation point (transmitted) from the point received in the circle. The point received is interpreted as representing the closest of the eight points in the constellation. In this way, the most likely error event is that a signal point is interpreted in the receiver as a constellation point that ft is adjacent to the one that is currently transmitted. Due to this characteristic impact of modulation interference, a common bit mapping to the constellation uses Gray encoding in order to minimize the number of bit errors for the most likely error event. Figure 11 illustrates such mapping. For each constellation point, the two closest neighbors in the circle are assigned bit combinations that differ in value at only one site. In this way, moving from a signal point to the signal point on the circle only one bit changes at a time. This type of mapping minimizes the number of bits in error when an error occurs. A Gray coding mapping may be appropriate when employing bending modalities of the present invention. However, when inter-symbol bending modalities are employed, other mappings according to the present invention can produce better demodulation results and add processing gain. For example, consider the exemplary bit mapping for an 8-PSK constellation illustrated in Figure 12 (a), which may be used in conjunction with the inter-symbol bending techniques described above. As mentioned above, when decoding the sub-channel for the other user first, one or more known bits can be identified for a symbol involving the sub-channel of interest. If the most significant bit (MSB = Most Significant Bit), say the leftmost bit assigned to each point in the constellation of Figure 12 (a) is known, then the demodulation problem is reduced to QPSK. For example, if the MSB is known to have a value of '1', then the constellation is reduced to that shown in Figure 12 (b). If the MSB is known to have a value of '0', then the constellation is reduced to that shown in Figure 12 (c).

Using the mapping illustrated in Figure 12 (a) for a .8-PSK modulation and the multi-user detection techniques described above, modulation can be more tolerant of interference and other signal transmission quality reductions than mapping encoded Gray illustrated in Figure 11. This can be easily observed by noting that the minimum distance between any of the remaining points in Figures 12 (b) and 12 (c) are 90 degrees apart, while the distance between the remaining points in Figure 11 is 45 degrees. However, this does not necessarily mean that the mapping in Figure 12 (a) is optimal for all applications. For example, the mapping in Figure 12 (a) is particularly deficient when the MSB is not known, since every point has as its neighbor an MSB of opposite value that maximizes the possibility that the erroneous constellation point it will be selected when the MSB is not known. By way of contrast, the mapping of Figure 11 is better than that of Figure 12 (a), where the MSB is not known. Other mappings will also have to be considered. For example, Figure 13 (a) illustrates an optional mapping for the MSB when the two least significant bits (LSBs = Least Significant Bits) are known. For each case, the remaining points are separated by 180 degrees. For example, as seen in Figure 13 (b), when the two LSBs are both zero, the remaining constellation effectively reduces to BPSK.

This mapping is also optimal for the case where MSB is detected without knowing the two LSBs as can be seen in the Figure 13 (c). There, it will be appreciated by those with skill in the specialty that, since four of the signal points have only one neighbor with a different MSB value and for the other four of the signal points, the neighbors have the same SFM values assigned, this represents an optimal mapping in terms of MSB detection. However, a weakness of the mapping illustrated in Figure 13 (a) becomes apparent when trying to determine the 2 LSBs when the MSB is known. Consider Figure 13 (d) where the MSB is considered to have a value of '1'. There, it can be seen that the signal points to the middle of the remaining four points both have neighbors with different values spaced 45 degrees, which is one of the worst possible results for combating interference (although nonetheless, they are encoded by Gray). However, another constellation mapping is illustrated in Figure 14 (a). This mapping may present a slight movement over the exemplary mapping of Figure 13 (a) for the case where MSB is known and the 2 LSBs are detected. This can be seen in Figure 14 (b), where the MSB has a value of '0', where it is apparent that the two remaining average signal points have the same LSB value. In this way, it will be apparent that changing the mapping of constellation used in the modulation process can provide different immunity and interference properties given the knowledge of one or more bits in each received symbol. Since the multi-symbolized intersymbol technique provided above provides that bits associated with two different sub-channels are placed in a symbol, the opportunity arises by selecting a preferred mapping. The selection of a particular mapping, however, depends on the channel coding involved in each ft sub-channel, the bit pattern used to select bits for the inter-symbol multiplexing, the system design and the desired result. For example, the most heavily protected bits (for example, class 1 bits in the D-AMPS example described above) of each user or connection can be mapped to a MSB of each symbol while using a mapping that maximizes the detection of these bits. Then, the re-coding / remodulation procedure previously described will make it easier to code the remaining 2 LSBs.

Another alternative is to increase the channel coding for the more highly protected bits of the source and use the mapping in Figure 12 (a). Since more channel coding is used, the performance associated with detecting these MSBs may be better than that for mapping in the Figure 11 even if the mapping is less favorable for MSBs per se. Then, since the remaining signal points in the constellation of the 'Figures 12 (b) or 12 (c) are optimally placed, less channel coding may be used to protect these bits. However, another alternative is to assign the largest channel coding to a few LSBs using the mapping in Figure 12 (a) and detect these bits first, this mapping is optimal for this form of detection. MSBs, which have the least favorable mapping in this constellation, can be assigned to the least important bits in a source. Another alternative is to use the mapping illustrated in Figure 13 (a) and assign bits in a stream of information to a few LSBs. These bits are detected again first, but the MSBs are now better located than in the previous example. If there is an uncoded class in the bit streams that are multiplied together, then the last alternative provides a better bit frame quality, when the channel condition is quite good. The above method increases the probability that the most important bits can be recovered correctly while the less important ft bits can more frequently have bits of errors. Still another strategy involves first detecting the MSBs using the mapping in either of Figures 13 (a) or Figure 14 (a), then after re-coding, detecting the LSB. In this detection, two of the four signal points have no close neighbors of different value. Then, after another re-encoding, potentially from a different channel, the remaining bit is detected. The receiver can first try with a channel. If you can not decode successfully (for example, when checking a CRC), the other channel is decoded (another bit). Since the channel coding is spread over several bits, and therefore several symbols, another channel can be decoded successfully, even when the first channel decoding fails. Subsequent re-encoding can reduce the number of errors in the symbol-to-bit detection, which can then allow or adjust the remaining errors in the channel which, in the first attempt may not be decoded by channel. Those skilled in the art will appreciate that for a particular strategy, especially if the three bits are detected in the three different instances with intermediate re-coding, better mappings than those illustrated here may be possible. Furthermore, different kinds of bits can be transmitted for each sub-channel. Each class of bits comprises those bits subjected to it, - channel coding protection. For example, one sub-channel may have class 1 and class 2 bits as described above, while other sub-channels transport data involving a third and possibly a fourth class of bits. Those skilled in the art will appreciate that these kinds of bits can be mapped using more than one bit-to-symbol mapping, ie in a symbol this class is mapped to a first subset of bits, while for another symbol this class is maps to a second subset of bits. > 'For each particular source, modulation method (eg 8-PSK, 16QAM, etc.), air interface (eg IS-136, GSM, IS-95, PDC, etc.), extensive computer simulations can be used to determine an optimal allocation of channel coding and multiplexing method of multiple users as described herein. For example, some symbols can be assigned to a single channel. If these symbols can be detected correctly, the next channel can use these symbols to estimate the state (phase) of the channel, ie using these symbols as pilot or reference symbols. In addition to these effects in modulation and demodulation techniques, general signaling and channel coding should also be considered. For the two voice sub-channels that are multiplexed in each time slot, common channel coding may be employed. However, in D-AMPS, the traffic channel frequency transposes a fast associated control channel (FACCH = Fast Associated Control Channel) that provides more urgent, general information to the mobile stations. There are two possibilities to handle the FACCH in the context of multiplexed ft of multiple users. First, as illustrated, for example in Figure 15, the speech and FACCH can be coded separately. In this example, the words FACCH are trimmed to fit in the average velocity portion of each time slot. Alternately, each FACCH can steal 2 speech frames or the amount of channel coding in the FACCH information can be reduced to fit in the average speed scheme. ft A second possibility is that the signaling FACCH may be common ('CFACCH') for both users joined in a medium speed channel. In this solution, the word length FACCH can remain the same as the full-speed FACCH. However, this solution affects both user A and user B (user's speech box B will also be blanked) even though the message is intended for only one user. In this way, the use of CFACCH will cause shorter interruptions, but are more frequent in the transmission of speech than the use of FACCH1 s coded differently for each user.

A discriminator within the word CFACCH can indicate the intended recipient, ie A, B or both. The CFAACH can be divided into two sub-fields, one for each user. Other general signaling may also require consideration when two users are multiple in a single time slot of * downlink. Consider the exemplary downlink slot formats of Figures 16 (a) (8-PSK) and * 16 (b). (8-DPSK) that are designed for full speed communication. In Figure 16 (a), the SYNC field provides synchronization bits to acquire synchronization alignment to the slot. The REF field provides reference symbols that can be used as a reference to help start the coherent demodulation of information. Several PLT fields are interleaved to provide pilot symbols. The pilot symbols provide phase reference information, such that the receiver can follow the varying effects over time of the radio channel on the transmitted information. Various fields of payload DATA (DATA) are also provided in this exemplary downlink time slot format. The end ramp field provides a period during which the transmitter can ramp down its output power to reduce interference from adjacent can. Figure 16 (b) illustrates an exemplary downlink slot format for differentially encoded modulated information. Since the & amp; differential coding, pilot symbols are not necessary. The structure of these exemplary integral rate downlink time slots may require certain operational settings in order to function with the multi-user multiplexing described above. For example, with two users per time slot, a Control function, e Energy (PC = Power Control), has to adjust the control of the output energy of the transmitters of each user. These exemplary downlink slot formats, however, only provide one power control bit. Two alternatives to control the output power of each user can be provided. First, an additional bit can be added to the power control field, with some implicit understanding among users as to which bit controls which user output power. Second, the use of this bit can be multiplied in time, for example user A can use the PC bit in time slot 1, while user B uses the PC bit in time slot 4. The first solution reduces payload data by one bit, while the second solution reduces the speed of the power control loop by a factor of two. For both full-speed and half-speed communications (one or two users per slot), the PC bit can be grouped into a multi-bit value before an interpretation of the PC data is performed. For example, after receiving two data time slots, the value 00 can mean no change, 01 increase with x dB, 10 increase with y dB and 11 can mean if change or reserved or increased with z dB. These changes (x, y, z) can also be filtered over time and, when the output of that filter makes the desired energy level that differs from the energy level (current by w dB, a change can be made. Of course, those skilled in the art will appreciate that it is not possible to use the above-described re-coding techniques if the encryption is applied after channel coding for example as in the D-AMPS example which is given above in Figure 4. If the encryption is applied after channel coding, then user A will not be able to decrypt the sub-channel information of user B, verify CRC and then re-encode / re-code the information for the second step. In contrast, exemplary embodiments of the present invention allow encrypted ft, (if any) to be applied prior to channel coding, for example in the speech frame. Finally, the mode signaling can be provided to inform the mobile stations of various effects created by the above exemplary embodiments of the present invention. For example, the following signaling may occur at the beginning of a call and during a call, including as part of a transfer command. With reference to the above described ft mode where only one currently active user transmits in a half-speed time slot, otherwise, the mobile station can be informed of the format (channel coding, other sub-channel data, etc.). ) of the second sub-channel. Furthermore, a flag can be sent to the mobile station informing whether the second sub-channel that is multiplexed in its designated time slots can be used for re-encoding as described above. Another signaling mode ft can include the use of PC bit (s) and if CFACCH is enabled. For example, a single bit flag may be sent to a mobile station indicating a mode packet, for example MMFLAG = 1, may mean that the mobile destination station shall transmit on the uplink in the time slot corresponding to its second one. link time slot ft descending in a frame, which will have to consider the non bits in each of its two downlink time slots assigned to understand its sub-channel, and which will see the bit P < ? in its second downlink time slot in each frame to adjust its power. Alternatively, the explicit information can be reduced by defining each of these characteristics for each sub-channel and then simply informing the mobile station to which sub-channel it is assigned. That is, for a multipoint scheme determined in accordance with the present invention, for example symbol bending, inter-symbol bending, or a combination thereof, two (or more) sub-channels are created. The mode signaling bit can indicate to the mobile on which sub-channel the information will be received, in response to which implicitly (through pre-programming) it will know which bits belong to the sub-channel, which energy control bit is associated with its energy of transmission, etc. Additional exemplary embodiments of the present invention will now be discussed to further illustrate how the above-described re-coding techniques can be applied to improve the demodulation / detection of multiple information streams. As will be appreciated by those skilled in the art, demodulation refers to the process of channel estimation and extraction of samples that are not very penetrating or smooth. Typically, both the phase and the amplitude of the channel are estimated to be used in the demodulation process. However, for some modulations or when no equalization or compensation is performed (for example without time dispersion) only the phase can be followed, words and synchronization pilots can be used to estimate the channel. When the modulation is contained in the absolute value of the symbol, for example the phase in 8PSK, it is important to undo any phase changes that the fading has introduced to the transmitted signal before coherent demodulation of the received signal. For dLferentially encoded signals, where the modulation is contained in one phase shift from one symbol to another, it may be important to accurately track phase changes of the channel before demodulation. However, differentially coded signals can first be coherently demodulated and subsequently differential decoding can be carried out to improve performance compared to a receiver that only searches for the phase difference between symbols. , -In this way, for modulation based on either an absolute or relative symbol value, there may be an interest in tracking the channel. Furthermore, when symbol interference due to time dispersion is present or when the modulation format contains information on the amplitude of the signal, for example 16 QAM, it is also of importance to track the amplitude of the channel which, due to fading Rayleigh can undergo rapid changes. The accuracy of the channel estimate will improve if re-encoding is performed as the bits are decoded. In this way, the two-step demodulation process described above can be generalized to periodically re-estimate the channel and use the re-estimated channel estimates in subsequent demodulations. The following provides an example of how this process can be done. Initially, due to different kinds of information streams based on their variant channel coding of each source box such as 1, 2, ... n. For purposes of this example, consider that the interleaving is interleaved diagonally < Jp two slots (as for IS-136 systems). In this example, each user Ul, U2, ... Uw receives and processes slots ..., m-2, m-1, m, m + l, m + 2, ..., etc. These slots are transmitted, using the example IS-136, in time slot pairs 1 &; 4 or 2 &5 or 3 &6. When processing the slot m in the receiver in order to generate the speech frame j, half of the bits in the time slot m is related to another speech frame (ie a speech frame j + 1) this another speech box includes bits that are also sent in time slot m + l (that is, because of the interleaving of two slots used in IS-136, see Figure 7). The demodulation of time slot m according to the present invention can be carried out as follows: It receives slot m for the final processing of the source frame j It demodulates decodes user class 1 bits Ul Re-encodes, re-interleaves using the decoded data ft Demodulates Decodes user class 1 bits U2 given the result of the pre-decode stage Re-encodes, re-interleaves using the decoded data Decodes class 1 bits of user Uw given the results of the previous decoding stages ft Re-encode, re-interleave using the decoded data Desmodulates Decodes class 2 bits of user Ul given the result of the previous decoding stages Demodulates Decodes user class 2 bits Uw given the result of the previous decoding stages ft Decodes class n of user Uw given the result of previous decoding stages Demodulates For each user Ul ... Uw, the source box j is now retrieved. The process can continue with time slot m + l to retrieve frame j + 1. Half of the bits in the time slot m will be used in the frame processing j + 1 that will occur during processing of the time slot m + l. In order to have the best quality samples of the time slot m when the time slot m + l is processed, one last of its demodulation of the slot m is performed after all the decoding for the slot m is terminated.

In addition, the least protected class (n) in the class set is often not protected in fact by error correction coding. A final demodulation after ft all protected classes are processed by improving the demodulation of the unprotected bits. As described in International Patent Publication No. WO 98/04047 formerly incorporated under the heading "Method and Apparatus for Detecting Communication Signals Having Unequal Error Protection" (Method and Apparatus for Detecting Communication Signals Having Non-Equal Error Protection), the feedback information to be used in the process of re-encoding, re-interleaving and remodulation can be smooth information (ie probability) to provide improved performance. For example, the modulation constellation in Figure 12 (a) may not be distinctly crushed to any of that shown in Figures 12 (b) or 12 (c). In contrast, the soft feedback information indicates a probability that the constellation of Figure 12 (b) is relevant and another probability that the constellation of Figure 12 (c) is relevant. Of course, the algorithm described above is only one of many variations in the subject of re-coding which can be used in conjunction with multi-user detection according to the present invention. For example, the estimation of the radio channel does not need to be performed after each simple class has been decoded for each user. It may be sufficient to just re-estimate the radio channel after the most protected bit class is decoded. Half of the bits in any slot, - time-bound will be used when processing a subsequent time slot. Therefore, it may be advantageous to perform a final channel and demodulation estimate when all channel decoding is completed for a burst in the interest of obtaining the highest possible data quality, when the decoding of the first selected class of data is initiated. bits and user in the subsequent burst. Furthermore, if there is an indication, for example by a CRC check or soft bit information, - previously decoded, that the information is not reliable, the receiver can jump to other user data to another class before proceeding to so as not to introduce further degradation of the samples received. The U.S. Patent No. 5,673,291 issued to Paul Dent (previously mentioned) further illustrates refinements that may be employed in the context of the present invention. For example, the channel estimate and channel decoding described above do not require separating into two distinct processes. For example, when a Viterbi channel decoder is used, each state may have a separate channel estimator, this state is updated for each decoded bit. Another ft 43 refinement is to decode information from multiple users and multiple classes in parallel. For each stage in the Viterbi decoder, modified power data to all other Viterbi decoders, can be produced. For speech transmission, the delay when processing the data should generally be minimized. However, if more delay can be tolerated than that which has already been introduced by the speech coder and the interleaving of two slots, it can achieve further improvement in performance. For example, when frame j is decoded (which happens after the processing of slot m ends), the data in slot m-1 that was used in the decoding of frame j during slot m, can be re-entered in slot m-1. The decoding of frame j-l can now be further improved. Having now improved the data in slot m-1 and since half of those bits are used in conjunction with data in slot m to form frame j, slot m can now be re-processed. In this way, performance can be improved by iterative processing. However, since frame j-l can not be released to the speech decoder until a slot later, this iterative processing introduces delay. A compensation between delay and better, in performance would be to free the box jl to the speech decoder, after the m-1 slot is processed, so that the iterative processing is used to improve the bits of the slot n- 1 that affect the box j. In this process, a copy stored in the j-l box is used. If the bits in the j-l box were changed, this will have no effect on the j-l box supplied to the speech decoder. Another, somewhat more elaborate example is to re-enter the bits now improved in slot m-1 to slot m-2 and then work forward in time to further improve the slot m-1 and finally slot m. It should be apparent to the person with skill in the specialty that many variations are possible. A simple yet practical example now appears with limited complexity to facilitate understanding and does not perform any iterative inter-slot processing. The source is a speech coder with three classes. The class which is protected with a CRC and encoded with a first encoding speed, class Ib has no CRC and is encoded with a second encoding rate and class 2 does not have CRC or channel coding. The algorithm is designed based on the consideration that the class is more protected (that is, it has lower coding speed and thus more redundancy) than the class Ib and that there is no FACCH type of interruption of the speech service (such as described above with respect to Figure 15. The following steps can be performed in this exemplary algorithm (expressions with italics are defined below): Receive slot m for the final processing of source box j.The assigned cabial is A. [1] Demodulates: Sets q = 0 [2] Decodes class of user A If CRC = OK THEN updates received date, Set q = a Decode class for user B If CRC = OK THEN update received date, Set q = q + a [3] Case 1: If user A CRC = Not OK and user B ft CRC = N? T OK THEN GOTO [ERR] Case 2: If user A CRC = OK and user B CRC = Not OK THEN GOTO [4] Case 3: If user A CRC = Not OK and user B CRC OK Decodes class of user A If user A CRC - OK, THEN updates received date ft, Sets q = q + a and GOTO [4], FROM OTHER FORM GO TO [ERR] ft 4é Case 4: If user A CRC = OK AND user B CRC = OK THEN GO TO [4] [4] If q > = a THEN re-adjust phase and Set q = 0 Decode class Ib of user A If _r¡etric = OK THEN update received date, / and Set q = q + b Decode © user Ib's B If _netric = OK THEN update date received, and set q = q + b [5] If q > = b THEN re-phase adjustment Decodes class 2 for user A Extracts class 2 bits for user A and all bits related to table j + 1 for both users [6] Sends frame j to speech decoder. ft Stores bits associated with the j + 1 box. GO TO [END] [ERR] Declare box j as non-decodable. Stores bits associated with the j + 1 table [END] It proceeds to decode table j + 1 In the previous exemplary algorithm, the term updated received date, means that the greater processing of the received data, the result of the ft decoding should be reflected (soft or hard information) in the further processing of the received data. The current formatting ft (channel re-encoding, interleaving, inter-symbol bending) is implicitly understood in the algorithm. The term demodulate means extract the soft es from the received burst. This includes the appearance of the first estimate and then compensates for the displacement of f (as introduced by Rayleigh fading.) Before demodulating, time synchronization has been performed where a set spaced in sample symbols has been extracted from a received signal over a sample. The term phase re-adjustment means improving the correction of the phase errors introduced by the Rayleigh fading using the decoded data. The e of the constants a and b in the previous example depends on the relative protection level of class a and class lb¿ & The intention is to adjust these constants to es such that the phase re-adjustment is performed only if the decoding has been sufficiently successful to guarantee a phase readjustment. Note that the following table (j + 1) can benefit from phase re-adjustment, even if the class can not recover correctly. In the previous example, a relative simple approach is taken to decide if the received samples will have to be re-adjusted in phase, that is to say after having decoded the class of both users, perform phase readjustment if at least one of the decoding steps It was successful. The phase reset is performed again if at least one of the Ib class information streams was decoded successfully. A more general example to determine whether readjustments will be made, could be by using a and b as variables that are set equal to quality metrics received from the channel decoder and then examining in each iteration described above if q > = c.

In this more general example, the e of c is a threshold e ft which can be determined based on simulations involving many es, including for example channel coding, and may vary depending on smooth outputs of the decoding processes. When the quality of the decoded class bits is eated, the CRC can be used as a quality indicator. For class Ib, an absolute or relative threshold of the selected path of the cost function of the Viterbi decoder can be used. A relative threshold can be to compare the metric of the selected route with the selected route of the class bits a, adjusted in scale with an appropriate ft 49 e, depending for example on the number of raw bits in class a and class Ib, respectively. It will be seen from the previous example that box j is discarded if none of the class bits of user A or user B provides a positive CRC check.

This arrangement was described in the previous example and simply to limit complexity for purposes of illustration. In most cases, higher bit processing of the class Ib bits will not allow a correct recovery of class bits. However, depending on the amount of channel coding used in each class, discarding the table when the CRC fails for class bits the, may be undesirable. In this way, the class Ib bits of user A can be decoded in step [3] instead of yielding. If successful, according to a metric, the decoding of the class bits can be retried. However, this latter approach increases the complexity of decoding. According to yet another exemplary embodiment of the present invention, the radio channel conditions with interference in the uplink can be addressed by switching between several of the transmission modes described above. An exemplary context in which interference radio channel conditions may arise is in systems limited in range where the The distance between a base station and a mobile station can be such that the interference in the radio channel can reduce the signal quality received in either the base station or the mobile station to unacceptable levels. This problem can be handled more easily for the downlink by increasing the antenna height at the base station and / or increasing the transmission power.

For example, the base station may be capable of transmitting at 50 W / carrier or more. However, the uplink is more problematic since the antenna size of the mobile can not be easily increased nor the power amplifiers used in mobile stations designed to withstand significant increases in transmission power, for example mobile stations can typically transmit at in the order of 0.6 W. In this way, when experiencing channel conditions with uplink interference, for example as detected based on the signal quality received at the base station, exemplary embodiments of the present invention allow that a user ft commutates, for example from the average speed transmission described above, to use full-speed bandwidth (eg bandwidth equivalent to two full-time slots per frame per user). The additional bandwidth can be used in several different ways to contribute additional bits that provide better signal quality received at the base station. For example, full-rate vocoding and channel coding can be employed that can provide additional robustness in the context of interference resistance. Alternatively, the vocoder of the average speed can still be used, but additional channel coding can be provided, the increased redundancy of which can be used to correct more errors. Still another alternative is to copy the bits of each time slot into the new time slots (full speed). This provides a form of diversity from which information may be combined or selected at the base station to improve the quality of the received signal. If the signal quality received at the base station improves in an acceptable proportion, the system can recognize the reduction of interference effects and return the mobile station to a medium speed transmission mode. Of course, as described above, changes in the transmission mode may be accompanied by convenient signaling to the mobile station to indicate the change. Although the invention has been described in detail with reference to only a few exemplary embodiments, those skilled in the art will appreciate that various modifications can be made without departing from the invention. For example, although the present invention has been described in conjunction with medium speed communications, those skilled in the art will appreciate that the concepts set forth herein may be extended at a rate of one third, speed of a quarter, etc., with users or sources additional multiple ados in the same bandwidth. Accordingly, the invention is defined only by the following claims which are intended to encompass all of their equivalents. ft

Claims (63)

1. f CLAIMS 1. A method for decoding information transmitted within a communication system, characterized in that it comprises the steps of: interleaving information associated with a first user and information associated with a second user, to generate an interleaved information block; transmit the interleaved information block in a time slot; de-interleave the information of the first user and the information of the second user in a receiver; and decoding the information of the first user, with bg i e in knowledge obtained from the decoding of the information of the second user. The method according to claim 1, characterized in that further the step of decoding further comprises the steps of: attempting to decode the information of the first user; decoding, if it is not successful in the previous step, at least a part of the i? -formation of the second user, to generate known information; and decoding the information of the first user using the known information. The method according to claim 1, characterized in that the decoding step further comprises the steps of: decoding at least a part of the information of the second user to generate known information; and decoding the information of the first user using the known information. 4. The method of compliance with the claim 2, characterized in that it further comprises the step of: dividing the information of the second user into a plurality of classes, each class associated with a different level of channel coding, wherein at least a part of the information of the second user is one of the plurality of classes. 5. The method of compliance with the claim 3, characterized in that it further comprises the step of: dividing the information of the second user into a plurality of classes, each class associated with a different level of channel coding, ^ wherein at least a part of the information of the second user is one of the plurality of classes. 6. The method of compliance with the claim 1, characterized in that the interleaving step further comprises the step of: multiplying the information of the first and second users on a symbol-by-symbol basis. t 7. The method according to the claim 2, characterized in that the step of multipleing further comprises the step of: providing a pattern of repetitive symbols, including at least one symbol containing bits only associated with the information of the first user followed by at least one symbol including bits only associated with the information of the second user. The method according to claim 7, characterized in that the repeated symbol patterns are alternating symbols. The method according to claim 1, characterized in that the interleaving step further comprises the step of: multiplying the information of the first and second users on a bit-by-bit basis, where at least one bit of the first user and at least one bit of the second user may be included in a symbol. The method according to claim 9, characterized in that the bending step further comprises the step of: providing a first symbol containing two bits of the first user's information and one bit of the second user's information, followed by a second symbol that contains two bits of the information of the second user and a bit of the information of the first user. 11. The method according to claim 1, characterized in that it further comprises the steps of: encrypting the information of the first and second users; and coding in channel the encrypted information of the first and second users. 12. A method for decoding received information wherein a plurality of user information ft is interleaved over a given period of time comprising the steps of: providing within the information of each user, at least a first and a second class, wherein the first class has more redundancy than the second class; decoding the first class of the information of a first user from the received information; re-encode the information received using the decoded information of the previous stage; decoding the first class of information of the second user from the information received, based on the first decoded class of the information of the first user; re-encode the information received using the decoded information of the previous stage; decoding the second class of information of the first user from the information received, based on the first decoded class of the information of the first and second users; re-encode the information received using the decoded information of the previous stage; and decoding the second class of information of the second user from the information received, based on the first decoded class of the information of the first and second users and the second class of the information of the first user. 13. The method according to claim 12, further comprising the step of: estimating a channel in which the received information is transmitted after each class of information has been decoded for each of the plurality of users. 14. The method according to claim 12, characterized in that it further comprises the step of: estimating a channel over which the received information is transmitted only after a more protected class of information has been decoded by each of the plurality of users 15. The method according to claim 12, further comprising the step of: estimating a channel over which the received information is transmitted after a final decoding step associated with the received information. 16. The method according to claim 12, characterized in that the decoding steps are performed in parallel. 17. A method to communicate compliance in a Radio communication system, characterized in that it comprises the steps of: interleaving the information of a first user ft and the information of a second user by providing a repeated symbol pattern including at 58 minus a symbol containing bits only associated with the information of the first user, followed by at least one symbol including bits only associated with the information of the second user, followed by at least one symbol containing bits only associated with the information of the first user; and transmit the information of the first and second users interspersed in a first time slot. 18. The method according to claim 17, characterized in that the pattern of repeated symbols comprises alternating symbols. 19. A method for communicating information in a radio communication system, characterized in that it comprises the steps of: interleaving the information of a first user and the information of a second user when multiplying the information of a first and second users on a base bit-by -bit, wherein at least one bit of the first user ft and at least one bit of the second user can be included in a symbol, and transmit the interleaved information of the first and second users in a first time slot. The method according to claim 19, characterized in that the step of multipleing further comprises the step of: providing a first symbol containing two bits of the information of the ft first user and a bit of second user information, followed by a second symbol containing two ft bits of the second user's information and one bit of the first user's information. The method according to claim 19, characterized in that it further comprises the steps of: decoding information of the first user; improve a channel estimate based on the decoded information; re-encode the information; and decoding the information to the second user, based on the improved channel estimate. 22. The method according to claim 17, characterized in that it further comprises the steps of: decoding information to the first user; improve a channel estimate based on the decoded information; re-encode the information; and decoding information to the second user, based on the estimate of the improved channel. The method according to claim 17, characterized in that it further comprises the step of: providing a predetermined number of time slots per frame; interleaving additional information to the first user and additional information to the second user in a second time slot within the frame; and transmit the second time slot. 24. The method according to claim 23, characterized in that the predetermined number is six. 25. The method according to claim 17, further comprising the step of: explicitly informing the first and second mobile stations of their assigned uplink time slots. 26. The method according to claim 25, characterized in that the step of explicitly reporting further comprises the step of: transmitting an information element including an identification of the allocated uplink time slots. 27. The method according to claim 17, characterized in that it further comprises the step of: implicitly informing the first and second mobile stations of their assigned uplink time slots. The method according to claim 27, characterized in that the step of implicitly reporting further comprises the step of: recognizing the allocated uplink time slots based on an information element transmitted to the first and second mobile stations with respect to to downlink time slots. 29. The method according to claim 19, characterized in that it further comprises the step of: explicitly informing the first and second mobile stations of their assigned uplink time slots. 30. The method according to claim 29, characterized in that the step of explicitly reporting further comprises the step of: transmitting an information element &including an identification of the allocated uplink time slots. 31. The method according to claim 19, characterized in that it further comprises the step of: implicitly informing the first and second mobile stations of allocated uplink time slots. 32. The method according to claim 31, characterized in that the step of implicitly informing further comprises the step of: recognizing the assigned uplink time slots, based on an information element transmitted to the first and second mobile stations with respect to the downlink time slots. 33. A method for communicating information in a radio communication system, characterized in that it comprises the steps; of: interleaving information of a first user and information of a second user; transmitting the information of the first and second users interspersed in a first slot of time associated with a radio channel; terminate a source of information for the second user; and continue transmitting the information of the first user in the first time slot of the radio channel. 3 . The method according to claim 33, characterized in that it also comprises the step of: switching the transmission of the information of the first user to use the entire first time slot. ft. The method according to claim 34, characterized in that it further comprises the step of: informing a mobile station of the switch. 36. The method according to claim 33, characterized in that it further comprises the step of: increasing a channel coding associated with the information of the first user, to replace information of the second user. 37. The method according to claim 33, characterized in that it further comprises the step of: providing arbitrary data to replace the information of the second user in the interleaving step. 38. The method according to claim 37, characterized in that the arbitrary data is subjected to vocoding and channel coding. ,. 39. The method according to claim 37, characterized in that the arbitrary data is subjected to channel coding but not to vocoding. 40. The method according to claim 37, characterized in that the arbitrary data is not subjected to vocoding or channel coding. 41. The > - method according to claim 37, characterized in that the arbitrary data is a repetition of the data of the first user. 42. A method for transmitting information from a first source and a second source in a radiocommunication system, characterized in that it comprises the steps of: interleaving bits of the first source and the second source together in a single symbol a: assigning at least one bit from the first source at least one more significant bit (MSB) of the simple symbol; and assigning at least one bit of the second source when it is less significant (LSB) of the simple symbol; and transmit the simple symbol, among other symbols. 43. The method according to claim 42, characterized in that the symbols are symbols 8-PSK and at least one MSB includes a bit of the first source and at least one MSB includes two bits of the second source. ,- 4 . The method according to claim 42, characterized in that it further comprises the steps of: assigning, as the MSB at least, highly protected bits of the first source; and employing a bit-to-symbol mapping that increases a detection probability of the MSB at least. 45. The method according to claim 44, characterized in that the highly protected bits are class 1 bits. 46. The method according to claim 42, characterized in that the first and second sources comprise different information streams directed to a base station. in a radio communication system. 47. A method for transmitting general information and payload information to first and second users assigned to the same channel in a radiocommunication system; characterized in that it comprises the steps of: coding ,, the payload information from the first and second users using a common channel coding; multiple $ ar coded payload information for the first and second users together on the same channel; encoding the general information using a channel encoding other than the common channel coding; multiply the general information encoded for the first and second users together in the same channel; and transmit the general coded and payload information. 48. The method according to claim 47, characterized in that the step of multiplying the encoded general information further comprises the step of: providing a different general word for each of the first and second users in the common channel. 49. The method according to claim 48, characterized in that the different general words, for each of the first and second users, are sized to fit in a time slot associated with the "somun" channel. 50. The method according to claim 47, characterized in that the step of multiplying the coded general information further comprises the step of: stealing separate frames for each of the general words other than the payload information to provide bandwidth where to transmit the general information. 51. The method according to claim 47, characterized in that the step of multiplying the coded general information further comprises the step of: providing, as the different channel coding, a reduced amount of channel coding in such a way that different words They occupy a single speech frame 52. The method according to claim 47, characterized in that the step of multiplying the coded general information further comprises the step of: providing a common general word for each of the first and second users in the Common channel 53. The method according to claim 51, characterized in that it further comprises the step of: providing a discriminator that identifies a intended recipient of the common general word, the method according to claim 53,? the discriminator identifies one of: the first user, the second user or both of the first and segúndo users as the intended recipient. 55. The method according to claim 47, characterized in that the common channel includes at least one time slot within a repeated frame structure. 56. A method for communicating with a first user and a second user assigned to the same downlink channel in a radio communication system, comprising the steps of: multiplying payload information of the first and second users within the same slot of time in the downlink channel; and transmitting power control information to the first and second users with the payload information. 57. The method according to claim 56, characterized in that the step of transmitting power control information to the first and second users with the payload information, further comprises the step of: providing a power control bit for each one of the first and second users within the time slot. 58. The method according to claim 56, characterized in that the step of transmitting power control information to the first and second users with the payload information further comprises the step of: providing a power control bit in the slot of time, this bit of control of ft power is used alternately to control the transmission power of the first user and the second user. 59. A method for communicating with a first user and a second user assigned to the same downlink channel in a radio communication system, comprising the steps of: multiplying payload information to the first and second users within a same time slot in the downlink channel; and transmitting at least one mode flag to the first and second users that identifies at least one usable parameter for processing the multiple payload information. 60. The method according to claim 59, characterized in that the flag at least indicates a format associated with the payload information multiplexed. 61. The method according to claim 59, characterized in that the flag at least indicates whether the sub-channel information associated with the payload information of the second user can be decoded and re-encoded before decoding the payload of the first user. 62. The method according to claim 59, characterized in that the flag at least indicates a form in which at least one power control bit is to be interpreted by the first and second users. 63. The method according to claim 59, characterized in that the flag at least indicates whether a common general word is sandwiched between the payload information for the first and second users.