RU2553677C2 - Method of transmitting multicast and broadcast service (mbs) traffic in wireless communication system - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: invention relates to wireless communication. Transmission of a multicast and broadcast service (MBS) in a multiple-input multiple- output (MIMO) communication system is carried out using one of three modes: a single-layer mode, a spatial multiplexing (SM) mode and a hierarchical mode. In the hierarchical mode, lower quality data are transmitted over a first MIMO layer and enhancement data are transmitted over a second MIMO layer. A receiving device may only successfully receive the lower quality data or may successfully receive the enhancement data to enhance the lower quality data. The transmission scheme used, including the mode used, may be selected, wherein selection may be performed based on feedback information.

EFFECT: improved method of transmitting MBS traffic.

13 cl, 16 dwg

Description

FIELD OF TECHNOLOGY

The present invention relates generally to wireless communication technologies and, more specifically, to symbol transmission in a MIMO scheme using Alamouti codes.

BACKGROUND OF THE INVENTION

The demand for wireless data services has grown in recent years, and this growth is expected to continue. This applies to applications in which data is transmitted by means of a cellular telephone or other mobile telephone, using personal communication systems and digital television or high-definition television (HDTV). Although the demand for such services is growing, the bandwidth of the lines through which data is transmitted is limited. Therefore, it is desirable to transmit data at high speed in this limited frequency band using efficient methods, including those that are economically efficient.

A well-known approach that provides efficient high-speed channel data transmission is orthogonal frequency division multiplexing (OFDM). Data signals transmitted at high speed are divided into tens or hundreds of signals with a lower transmission rate, which are transmitted in parallel at the corresponding frequencies within the radio frequency spectrum, which are called subcarrier frequencies. The subcarrier frequency spectra overlap, so that spacing between them is minimized. Subcarriers are also orthogonal to each other, so that they are statistically independent and do not create cross-talk or other interference with each other. As a result, channel bandwidth is used more efficiently than traditional single-carrier transmission schemes, such as amplitude or frequency modulation (AM or FM).

Spatial-temporal diversity transmission can provide diversity levels of characters, which significantly increases the bandwidth of the communication line. Therefore, it is said that the space-time diversity code is “ideal” in the sense that it uses the full space-time coding rate (space-time coding rate = 1, “rate-1” is also indicated), and it is orthogonal. However, if the number of transmitting antennas is greater than 2, then orthogonal “rate-1” codes do not exist.

Another approach that makes more efficient use of channel bandwidth is to transmit data using a base station having multiple antennas and receiving transmitted data using a remote station having many receiving antennas, so-called multi-input multi-output (MIMO) systems. MIMO technologies are offered for next-generation cellular communications systems, such as those operating under the standards of the Third Generation Partnership Project (3GPP). Since the transmitter and receiver have multiple antennas, higher throughput or higher transmission rates can be achieved.

If the MIMO system is used to transmit packets and there is an error in the received packet, the receiver may request a retransmission of this packet. Known systems that use the display of packet symbols that are different from the original transmitted data.

A particular problem of modern wireless data transmission systems is the efficient and reliable provision of multicast and broadcast information transfer (MBS) services. Known technical solutions have various disadvantages. For example, they do not provide satisfactory address coverage of the zone or do not have sufficient reliability.

Thus, there is a need for an improved method for transmitting an MBS schedule.

SUMMARY OF THE INVENTION

The invention provides a method for providing multicast and broadcast information services using a multi-input-many-output (MIMO) scheme. The method includes transmitting first data at a first MIMO level, the first data being low quality data. The method also includes transmitting second data using a second MIMO layer, the second data being enhancement data providing improved data of poor quality. MBS transmission should be determined at the subscriber station as a result of improving low-quality data with improving data if the first and second data were successfully received, and MBS transmission should be determined at the subscriber station only with poor quality data if the first data was successfully received and the second not.

The invention provides yet another method of providing a multicast and broadcast information service using a multi-input-many-output (MIMO) scheme. The method includes transmitting first data at a first MIMO level, the first data being low quality data. The method also includes deciding to transmit second data using a second MIMO layer, the second data being enhancement data providing improved data of poor quality. MBS transmission should be determined at the subscriber station as a result of improving low-quality data with improving data if the first and second data were successfully received, and MBS transmission should be determined at the subscriber station only with poor quality data if the first data was successfully received and the second not.

The invention also provides a method for transmitting a multicast and broadcast information service schedule using a multi-input-multiple-output (MIMO) scheme. The method includes selecting a transmission format for transmitting MBS data from the available transmission formats, each of which has a transmission mode. The method also includes transmitting the MBS schedule using the selected transmission format. The many available transmission formats include at least one transmission format comprising one transmission mode selected from the group consisting of a transmission mode at one level, a spatial multiplexing (SM) mode and a hierarchical mode, and at least another transmission format containing a different transmission mode selected from the group containing the transmission mode at one level, spatial multiplexing (SM) mode and hierarchical mode.

Other features and features of the present invention will become apparent to those skilled in the art upon review of the following description of specific embodiments of the invention, together with the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

The following describes embodiments of the present invention, which are merely examples, with reference to the accompanying figures of the drawings, which show:

figure 1 is a General diagram of a cellular communication system;

figure 2 is a block diagram of an example of a base station that can be used to implement some variants of the present invention;

figure 3 is a block diagram of an example of a wireless terminal that can be used to implement some variants of the present invention;

figure 4 is a block diagram of an example of a relay station, which can be used to implement some variants of the present invention;

5 is a logical block diagram of an example OFDM transmitter that may be used to implement some embodiments of the present invention;

Figure 6 is a logical block diagram of an example OFDM receiver that can be used to implement some embodiments of the present invention;

Figure 7 - Figure 1 of IEEE 802.16m-08 / 003r1, an example of a common network architecture;

figure 8 - figure 2 of IEEE 802.16m-08 / 003r1, a relay station in a common network architecture;

figure 9 - figure 3 of the document IEEE 802.16m-08 / 003r1, the basic model of the system;

figure 10 - figure 4 of the document IEEE 802.16m-08 / 003r1, the structure of the protocol standard IEEE 802.16 t;

figure 11 - figure 5 of the IEEE 802.16m-08 / 003r1 document, a block diagram of the processing of the data stream transmitted between the mobile station (MS) and the base station (BS) for the IEEE 802.16m standard;

figure 12 - figure 6 of the IEEE 802.16m-08 / 003r1 document, a block diagram of the processing of control information transmitted between the mobile station and the base station for the IEEE 802.16m standard;

Figure 13 - Figure 7 for the IEEE 802.16m-08 / 003r1 standard, architecture of a common multi-carrier system support protocol;

figure 14 is a General diagram of a cellular communication system in which an MBS figure is supported

15 is a block diagram of a DL subframe containing an MBS zone;

Figure 16 is a block diagram of a DL subframe containing an MBS zone on which unicast data is superimposed.

To indicate similar elements in different figures, the same reference numbers are used.

DETAILED DESCRIPTION OF THE INVENTION

1 illustrates a base station controller (BSC) 10 that controls wireless communications within cells 12 served by respective base stations (BS) 14. In some configurations, each cell is further divided into sectors 13 or zones (not shown). In general, each base station 14 communicates using an OFDM system with subscriber stations (SS) 16, which may be any device that communicates with the base station, and may include mobile and / or wireless terminals or fixed terminals that reside in within the cell 12 associated with the corresponding base station 14. If the subscriber stations 16 move relative to the base stations 14, then this movement can lead to significant fluctuations in the characteristics of the channel. As shown in figure 1, base stations 14 and subscriber stations 16 may contain several antennas to provide spatial separation of signals. In some schemes, relay stations 15 may be used to assist in communication between base stations 14 and subscriber terminals 16. Subscriber station 16 may be transmitted from any cell 12, sector 13, zone (not shown), from base station 14 or relay station 15 to another cell 12, sector 13, a zone (not shown), a base station 14 or a relay station 15. In some configurations, the base stations 14 communicate with each other and with another network (such as a core network or the Internet, not shown) Transit network 11. In some configurations, the controller 10 is not used by the base stations.

The figure 2 presents a diagram of one of the variants of the base station 14. The base station 14 generally comprises a control system 20, a baseband processor 22, a radio transmission circuit 24, a radio receiving circuit 26, an antenna 28, and a network interface 30. Radio receiving circuits 26 carry out the reception of information-carrying radio frequency signals transmitted by one or more remote transmitters of subscriber stations 16 (see figure 3) and relay stations 15 (see figure 4). A low noise amplifier and filter (not shown) can provide signal amplification and eliminate wideband interference from it. After this, the signal conversion circuits with decreasing frequency and digitization (not shown) convert the received filtered signal into a signal at an intermediate or fundamental frequency, which is then converted to digital form with the formation of one or more streams of digital information.

The baseband processor 22 processes the received digitized signal to extract information or data bits carried by the received signal. This processing typically includes demodulation, decoding, and error correction. The baseband processor 22 is typically implemented on one or more digital signal processors or on specialized integrated circuits. Then, the received information is transmitted wirelessly through a network interface 30 or transmitted to another subscriber station 16 served by the base station 14, directly or through a relay 15.

On the transmitting side, the baseband processor 22 receives digitized data, which may be voice, data or control information, from the network interface 30 under the control of the control system 20 and encodes the data for transmission. The encoded data is transmitted to the circuit 24 of the radio transmission path, where they modulate one or more carrier signals having the desired frequency or frequencies of transmission. A power amplifier (not shown) amplifies the modulated carrier signals to a level suitable for transmission and directs the modulated carrier signals to antennas 28 through matching circuits (not shown). The processes of modulation and processing are described in more detail below.

The figure 3 presents a diagram of one of the options for the subscriber station 16. The subscriber station 16 may be, for example, a mobile station. Just as the base station 14, the subscriber station 16 includes a control system 32, a baseband processor 34, a radio transmission path circuit 36, a radio path circuit 38, an antenna 40, and a user interface circuit 42. Radio path circuits 38 receive information-carrying radio frequency signals transmitted by one or more base stations 14 and relay stations 15. A low noise amplifier and filter (not shown) can provide signal amplification and exclude broadband interference from it. After this, the signal conversion circuits with decreasing frequency and digitization (not shown) convert the received filtered signal into a signal at an intermediate or fundamental frequency, which is then converted to digital form with the formation of one or more streams of digital information.

The baseband processor 34 processes the received digitized signal to extract information or data bits carried by the received signal. This processing typically includes demodulation, decoding, and error correction. The baseband processor 34 is typically implemented on one or more digital signal processors and on specialized integrated circuits. To transmit information, the baseband processor 34 receives digitized data, which may be voice, data, or control information, from the control system 32 and encodes the data for transmission. The encoded data is transmitted to the circuit 36 of the radio transmission path, where it is used by the modulator to modulate one or more carrier signals having the desired transmission frequency or frequencies. A power amplifier (not shown) amplifies the modulated carrier signals to a level suitable for transmission and directs the modulated carrier signals to the antennas 40 through matching circuits (not shown). Specialists in the art are aware of various modulation and processing technologies that are used to transmit signals between a subscriber and base station, either directly or through a relay station.

Using OFDM modulation, the transmission band is divided into multiple orthogonal frequency subcarriers. Each subcarrier frequency is modulated by digital data to be transmitted. Since the division of the transmission band into a plurality of subcarriers is performed during OFDM modulation, the frequency bandwidth for each carrier frequency decreases, and the modulation time increases compared to the case of using one carrier frequency. Since all subcarrier frequencies are transmitted simultaneously (in parallel), the transmission rate for digital data or symbols (discussed below) at a certain given subcarrier frequency is lower than in the case of a single carrier.

OFDM modulation uses the inverse fast Fourier transform (IFFT) of the information to be transmitted. When demodulating, a fast Fourier transform of the received signal (FFT) is performed, which ensures the extraction of the transmitted information. In practice, IFFT and FFT are performed using digital signal processing, which performs the inverse discrete Fourier transform (DFT) and discrete Fourier transform (DFT), respectively. Accordingly, a characteristic feature of OFDM modulation is the formation of orthogonal frequency subcarriers for multiple bands in the transmission channel.

Modulated signals are digital data having a relatively low transmission rate and capable of being within their respective frequency bands. Individual subcarriers are not directly modulated by digital signals. Instead, all subcarriers are modulated simultaneously using IFFT.

Typically, OFDM modulation is preferably used for at least downstream transmission from base stations 14 to subscriber stations 16. Each base station 14 has “n” transmit antennas 28 (n≥1), and each subscriber station 16 has “m” receive antennas 40 (m≥1). Moreover, it should be borne in mind that, in principle, both transmitting and receiving antennas can be used for both reception and transmission using appropriate antenna switches.

When relay stations 15 are used, OFDM is preferably used for downstream transmission from base stations 14 to relays 15 and further to subscriber stations 16.

The figure 4 presents a diagram of one of the options of the relay station 15. Just like the base station 14 and the subscriber station 16, the relay station 15 includes a control system 132, a baseband processor 134, a radio transmission path circuit 136, a radio reception path circuit 138, an antenna 130 and relay module circuits 142. The relay module circuits 142 provide the relay 15 with the ability to communicate between the base station 14 and the subscriber stations 16. The radio path circuits 138 receive information-carrying radio frequency signals transmitted by one or more base stations 14 and the subscriber stations 16. The low noise amplifier and filter ( not shown) can provide signal amplification and the exclusion of broadband interference from it. After this, the signal conversion circuits with decreasing frequency and digitization (not shown) convert the received filtered signal into a signal at an intermediate or fundamental frequency, which is then converted to digital form with the formation of one or more streams of digital information.

The baseband processor 134 processes the received digitized signal to extract information or data bits carried by the received signal. This processing typically includes demodulation, decoding, and error correction. The baseband processor 134 is typically implemented on one or more digital signal processors and on specialized integrated circuits.

To transmit information, the baseband processor 134 receives digitized data, which may be voice, data, or control information, from the control system 132 and encodes the data for transmission. The encoded data is transmitted to a radio path circuit 136, where it is used by a modulator to modulate one or more carrier signals having a desired transmission frequency or frequencies. A power amplifier (not shown) amplifies the modulated carrier signals to a level suitable for transmission and directs the modulated carrier signals to antennas 130 through matching circuits (not shown). Specialists in the art are aware of various modulation and processing technologies that are used to transmit signals between a subscriber and base station, either directly or through a relay station, as already indicated.

Below with reference to figure 5 describes the logical architecture of the transmission process using the OFDM scheme. First, the base station controller 10 transmits to the base station 14 data to be transmitted to the subscriber stations 16, either directly or through the relay station 15. The base station 14 can use the quality information of the channel associated with the subscriber stations to schedule data for transmission as well as to select suitable coding and modulation schemes for transmitting scheduled data. The quality of the channel is determined using control messages, as described below. However, generally speaking, the channel quality for each subscriber station 16 is determined by the degree of change in the signal amplitude (or amplitude-frequency characteristic) in the channel in the OFDM frequency band.

The scheduled data 44, which is a bitstream, is scrambled using the scrambling logic 46 in such a way as to reduce the magnitude of the ratio of peak and average powers associated with the data. For the scrambled data, a cyclic control code (CRC) may be determined, which is added to the scrambled data using the CRC code logic 48. Then, channel coding is performed using channel coding logic 50 to efficiently introduce redundancy in the data to allow error detection and correction at the subscriber station 16. The channel coding for a particular subscriber station 16 may be determined by the quality of the channel. In some embodiments, the channel coding logic 50 uses a known turbo coding scheme. After that, the encoded data is processed using a data rate matching logic 52 to compensate for the increase in data volume associated with the encoding.

To interleave the bits in the encoded data, an interleaving logic 54 is used to minimize the loss of consecutive data bits. The resulting sequence of data bits in an ordered manner is mapped by the logical mapping 56 to the corresponding symbols determined by the selected modulation scheme. For example, the following modulation schemes may be used: quadrature amplitude modulation (QAM), quadrature phase modulation (QPSK) or relative phase modulation (DPSK). For the transmitted data, the modulation depth can be selected depending on the quality of the channel for a particular subscriber station. The symbols can be rearranged in an orderly manner using the symbol interleaving circuitry 58 to further increase the stability of the transmitted signal to periodic data loss caused by frequency selective fading (fading).

At this stage, groups of bits are mapped to symbols representing points in the signal amplitude and phase diagram (constellation). When it is necessary to use spatial separation, the blocks of symbols are further processed using a coding logic 60 to obtain spatio-temporal block codes, as a result of which the transmitted signals become more resistant to interference, and their decoding in a subscriber station is simplified 16. Logic - coding “n” The control system 20 and / or the baseband processor 22, as described with reference to FIG. 2, will provide a display control signal q I process control STC-coding. At this stage, the symbols for the "n" outputs represent data that must be transmitted and which can be extracted at the subscriber station 16.

For the present embodiment, it is assumed that the base station 14 has two antennas 28 (n = 2), and the STC coding logic 60 provides two output symbol streams. Accordingly, each of the symbol streams generated by the IFFT encoding logic 60, shown separately for better understanding. Those skilled in the art will understand that to provide such digital signal processing, one or more processors may be used, individually or in combination with other processors discussed herein. OBPF processors 62 will preferably process the corresponding symbols to perform the inverse Fourier transform on them. At the output of the OBPF processors 62, symbols in the time domain are provided. Characters are grouped in the time domain into frames that are associated with the prefix using the prefix logic 64. Each received signal is converted by transferring it to a higher intermediate frequency, and then converted into an analog signal using the corresponding circuit 66 increase the frequency and digital-to-analog conversion. Then, at the same time, the required radio frequency is modulated by the received analog signals, amplified and transmitted through the RF path circuit 68 and antenna 28. It should be noted that the pilot signals known to subscriber station 16, the intended recipient of the information, are distributed between subcarrier frequencies. Subscriber station 16 will use these pilots to evaluate channel quality.

Figure 6 illustrates the reception of the transmitted signals by the subscriber station 16, either directly from the base station 14, or through the relay 15. After receiving the transmitted signals of each of the antennas 40 of the subscriber station 16, these signals are demodulated and amplified by the corresponding RF circuit 70. In the interest of brevity and clarity, only one of the two receiving paths is shown in FIG. 6. Schemes 72 of the analog-to-digital conversion and frequency conversion (reduction) carry out the digitization and conversion of the received analog signal for digital processing. The resulting digital signal can be used by automatic gain control circuits 74 to control the gain of the RF circuit 70 depending on the level of the received signal. First, a digital signal is supplied to the input of the synchronization logic 76, which comprises a coarse synchronization circuit 78, which provides buffering of several OFDM symbols and calculation of the autocorrelation function for two consecutive OFDM symbols. The obtained time indicator, corresponding to the maximum of the calculated correlation, sets the time window for accurate synchronization, which is used by the exact synchronization circuit 80 to determine the exact starting position of the frame based on the headers. The output of the accurate timing circuit 80 provides a frame by the frame alignment circuit 84. Proper frame alignment is important that subsequent processing using FFT provides accurate conversion from the time domain to the frequency domain. The exact synchronization algorithm is based on the correlation between the received pilot signals contained in the headers and a local copy of the known pilot information. After the frame is aligned, the OFDM symbol prefix is removed by the prefix removal circuit 86, and the resulting symbol sets are sent to the frequency offset correction circuit 88, which compensates for the system frequency shift due to the lack of synchronization of the local transmitter and receiver generators. In preferred embodiments, the synchronization logic 76 includes a frequency and time offset estimation circuit 82 that uses headers to evaluate the effect of these offsets on the transmitted signal and transmits these estimates to the correction circuit 88 for proper processing of the OFDM symbols.

At this stage, the OFDM symbols in the time domain are ready for conversion to the frequency domain using the logic 90 using FFT. As a result of the conversion, symbols in the frequency domain are obtained, which are fed to the input of the processing logic 92. The processing circuit 92 provides the extraction of the distributed pilot signal using the distributed signal extraction circuit 94, then, based on the extracted pilot signal, performs channel estimation using the circuit 96 and provides channel frequency characteristics for all frequency subcarriers using the channel reconstruction circuit 98. To determine the frequency response of the channel for each subcarrier, the pilot signal is a plurality of pilot symbols scattered over data symbols transmitted on OFDM subcarriers according to a known pattern in both time and frequency domains. In processing logic 92, received pilot symbols are compared with pilot symbols calculated for specific subcarriers at specific time intervals to determine the channel frequency response for the subcarriers on which these pilot symbols were transmitted. In this case, interpolation is performed to estimate the channel frequency response for most, if not all, of the remaining frequency subcarriers for which pilot symbols are not provided. The actual and interpolated channel frequency responses are used to estimate the overall channel frequency response, which includes the frequency responses for most, if not all, of the subcarriers in the OFDM channel.

Symbols in the frequency domain and channel reconstruction information, which are obtained from the channel frequency characteristics for each signal receiving path, are supplied to the input of the STC decoder 100, which performs STC decoding in both receiving paths to recover the transmitted symbols. The channel reconstruction provides an STC decoding circuit 100 with information to correct a frequency response sufficient to eliminate distortions introduced by the transmission channel when processing the corresponding symbols in the frequency domain.

The logic of the reverse interleaving, the logic of which corresponds to the logic of the circuit 58 of the transmitter, performing the interleaving of characters, restores the sequence of the extracted characters. Then, the demapping logic 104 demodulates or demaps the resulting symbol sequence. After this, the bit interleaving circuit 106, whose operation logic corresponds to the operation logic of the transmitter circuit 54 interleaving the bits, restores the original bit order. After that, the obtained bit sequence is processed by the data rate backward correction circuit 108 and fed to the channel decoder circuit 110 for recover scrambled data and CRC checksum. Accordingly, the circuit 112 removes the CRC checksum, normally checks the scrambled data and provides it to the descrambling logic 114, which decrypts using the known descrambling code of the base station to obtain the source data 116.

Simultaneously with data recovery 116, a CQI signal (channel quality indicator) is determined, which contains an indication of the channel quality or at least information sufficient to obtain some knowledge of the quality of the channel at base station 14 and is transmitted to base station 14. The signal transmission is described in more detail below. CQI. As already noted, the value of the CQI parameter can be determined by the ratio of the signal power at the carrier frequency to interference (CR), as well as the degree of change in the frequency response of the channel for different subcarriers in the OFDM frequency range. For example, to determine the degree of change in the frequency response of a channel in the OFDM frequency range, the channel gain for each subcarrier used to transmit information can be compared for different subcarriers. Although there are various methods for measuring the degree of change in the channel frequency response, a method must be used to calculate the standard deviation of the channel gain for each subcarrier in the OFDM frequency band used for data transmission. In some embodiments, the relay station may operate in a time-sharing manner using only one radio means, or several may be used.

In figures 1-6 presents one specific example of a communication system that can be used to implement it variants of the present invention. It should be understood that the variants of the present invention can be implemented in communication systems whose architecture is different from the architecture of this particular example, but they work in accordance with the implementation of the options, as indicated in the present description.

7 illustrates a basic network model, which is a logical diagram of a network that supports wireless communication between base stations 14, subscriber stations 16, and relay stations 15 in accordance with a non-limiting embodiment of the present invention. The basic network model indicates the functional components and reference points at which the interaction between these functional components takes place. In particular, the basic network model may comprise a subscriber station 16, an access service network (ASN) and a connection service network (CSN).

An ASN can be defined as a complete set of network functions necessary for providing radio communication with a subscriber (for example, with a subscriber of the IEEE 802.16e / m system). An ASN may contain network elements such as base stations (BSs) 14 and one or more ASN gateways. One ASN can be shared by multiple CSNs. ASN can provide the following features:

- Ability to connect to subscriber station 16 at levels 1 and 2;

- Transmission of AAA messages (authentication, authorization and session accounting) to the subscriber's home network service provider for authentication, authorization and session accounting for subscriber sessions;

- Network discovery and selection of the preferred subscriber network services provider;

- The functions of the relay for establishing a connection of level 3 with the subscriber station 16 (for example, the assignment of an IP address);

- Radio resource management.

In addition to the above functions, for wearable and mobile stations, ASN can also support the following functions:

- Providing mobility with reference to the ASN;

- Providing mobility with reference to the CSN;

- call;

- Tunneling ASN - CSN.

A CSN can be defined as a set of network functions that provide a subscriber with IP connection services. The CSN can provide the following features:

- Assigning the IP address of the subscriber station and the terminal device parameters for user sessions;

- Server or proxy server for authentication, authorization and session accounting;

- Management of policies and access in accordance with subscriber profiles of users;

- Support for ASN-CSN tunneling;

- Billing for subscribers and settlements between operators;

- Tunneling between CSNs to ensure roaming;

- Mobility between ASN.

The CSN can provide location-related services, point-to-point connection services, registration, authorization, and / or IP connectivity to multimedia services. A CSN can also contain network elements such as routers, proxies / authentication, authorization and session accounting servers, user databases, and firewalls. In the case of IEEE 802.16m, the CSN can be used as part of the IEEE 802.16m network service provider or as part of the IEEE 802.16e network service provider.

In addition, relay stations 15 may be used to improve coverage and / or throughput. As shown in FIG. 8, a base station 14, which can support legacy relay stations, communicates with such a station in a “legacy equipment zone”. Base station 14 there is no need to support a protocol for working with outdated equipment in the "zone 16m". The structure of the relay protocol may be based on the structure of IEEE 802-16j, although it may differ from the IEEE 802-16j protocols in the "legacy equipment zone".

Figure 9 is a diagram of a basic system model that applies to both base station 14 and subscriber station 16, and contains various functional blocks, including a sublayer of the common part of medium access control (MAC), a convergence sublayer, a security sublayer, and a physical layer (PHY).

The convergence sublevel maps external network data received through the SAP convergence sublayer to the MAC service data blocks received by MAC CPS via MAC SAP, classifies the external network service data blocks and associates them with the SFID and CID MAC, suppresses / compresses useful information headers (for end user).

The security sub-layer provides authentication, secure key exchange and encryption.

The physical layer performs the protocol and functions of the physical layer.

The following describes in more detail the sublayer of the common part of the MAC. First of all, you need to understand that medium access control (MAC) is connection oriented. That is, for the purpose of displaying services at a subscriber station 16 and linking various levels of quality of services (data is transferred from the point of view of “connections.” In particular, “service flows” can be provided when the subscriber station 16 is installed in the system. Shortly after registering the subscriber connection stations 16 communicate with these service flows (one connection per service stream) to provide a reference point for which bandwidth is requested. Further, new connections can be established When the user’s service needs to be changed, the connection defines both the conversion of convergence processes belonging to the same level that use the MAC and the service flow. The service flow determines the QoS parameters for the MAC protocol data units exchanged on the connection. streams are an integral part of the bandwidth allocation process, in particular, the subscriber station 16 requests bandwidth for uplink communication per connection (implicitly Breaking up service flow). The bandwidth can be assigned by the base station of the mobile station in response to connection requests from the mobile station.

As shown in FIG. 10, the MAC Common Part Sublayer (CPS) is divided into radio resource organization and management (RRCM) and medium access control (MAC) functions.

RRCM functions include several function blocks that are associated with radio resource functions, such as:

- Radio resource management

- Mobility Management

- Manage network entry points

- Location management

- Standby control

- Security Management

- System configuration management

- MBS (multicast and broadcast services)

- Management of service flows and connections

- Relay features

- Self-organization

- Carrier Separation

Radio Resource Management

The radio resource control unit corrects the parameters of the radio communication network depending on the network load on the schedule and also includes the functions of load management (load balancing), connection control and anti-interference.

Mobility management

The mobility management unit supports functions related to the transfer of connections within / between RATs. The mobility management unit generates and maintains a network topology within / between the RATs, which includes announcements and measurements, manages possible connections of the base station and mobile stations in the vicinity, and also decides to transfer the connection of the mobile station within / between the RATs.

Manage network entry points

The network entry point control unit is responsible for initialization and access procedures. The control unit for points of connection to the network can generate control messages that are necessary in access procedures, namely, when determining the range, when exchanging basic parameters, during registration, etc.

Location Management

The location control unit is responsible for supporting location-related services (LBS). The location control unit may generate messages containing LBS information.

Standby control

The standby control unit controls the standby location update operation. The standby control unit controls the standby mode and generates ring messages based on the information of the call controller in the core network.

Security management

The security control unit is responsible for authentication / authorization and key exchange processes to ensure the security of data transmission.

System configuration management

The system configuration control unit organizes system configuration parameters, as well as system parameters and system configuration information for transmission to a mobile station.

MBS (Broadcast and Multicast Services)

The MBS (Broadcast and Multicast Services) block manages the messages and data associated with the broadcast and / or multicast services.

Service Flow and Connection Management

The service flow and connection control unit assigns “subscriber station identifiers” (or station identifiers - STIDs) as well as “flow identifiers” (FIDs) when performing access, transfer and service flow creation procedures. Station and stream identifiers will be discussed below.

Relay Features

The relay function block provides support for relay mechanisms with many retransmissions. These functions include procedures for maintaining relay paths between the base station and the access relay station.

Self-organization

The self-organization unit performs the functions of supporting the mechanisms of the system for its configuration and optimization. These functions include the procedure for requesting relay and mobile stations to transmit measurements to configure and optimize the system and receive the requested measurements.

Carrier separation

The carrier separation unit provides control of the distribution of the physical layer across multiple frequency channels. Channels can have different bandwidths (for example, 5, 10 and 20 MHz), which can be adjacent to each other, or there can be gaps between them. Channels can have the same or different duplex modes, for example, FDD, TDD, or they can represent a combination of bidirectional and broadcast channels only. For adjacent frequency channels, overlapping guard subcarriers are aligned in the frequency domain for use in data transmission.

Media access control (MAC) includes functional blocks that are associated with physical layer and communication channel controls, such as:

- Physical layer management (PHY)

- Transfer of control information

- Management in a standby mode

- Quality of service (QoS)

- Planning and pooling resources

- Automatic repeat request (ARQ)

- Fragmentation / packaging

- MAC Protocol Data Unit Formation (MAC PDU)

- Simultaneous work on different radio standards

- Data Forwarding

- Anti-jamming

- Coordination of base stations

Physical Layer Management (PHY)

The PHY control unit includes functions for receiving and processing PHY signaling information, such as ranging, measurement / feedback (CQI), and positive / negative receipts for automatic retransmission requests (HARQ ACK / NACK). Based on the CQI and HARQ ACK / NACK information, the PHY control unit determines the quality of the channel as it is estimated by the mobile station and adapts the channel by correcting the modulation and coding schemes (MCS) and / or transmit power. When performing the ranging process, the PHY control unit synchronizes in the uplink with power adjustment, frequency shift and time estimates.

Management Information Transfer

The control information transmission unit generates resource allocation messages.

Standby Control

The control unit in standby mode ensures the execution of the standby procedure. The standby control unit may also generate MAC signaling information related to the standby mode, and may exchange information with the resource scheduling and pooling unit to ensure proper standby operation.

Quality of Service (QoS)

The QoS block manages the QoS using the QoS parameters coming from the service flow and connection control block for each connection.

Resource Planning and Pooling

The resource planning and pooling unit plans and combines packages according to the characteristics of the connections. To take into account the characteristics of the connections, the resource scheduling and pooling unit receives QoS information from the QoS block for each connection.

Auto Query (ARQ)

The ARQ block performs the MAC level ARQ function. For connections to ARQ, the ARQ block splits the logical service MAC data blocks into ARQ blocks and numbers each logical ARQ block. The ARQ block may also generate ARQ control messages, such as a feedback message (ACK / NACK information).

Fragmentation / packaging

The fragmentation / packaging unit performs fragmentation or packaging of data blocks of mobile stations in accordance with the results of the operation of the planning and pooling unit.

MAC Protocol Data Unit Formation (MAC PDU)

The MAC PDU generation unit generates them in such a way that the base station and the mobile station can transmit the user schedule or control messages to the PHY channel. The MAC PDU generates a MAC header and can add subheadings.

Simultaneous work on different radio standards

The simultaneous operation unit for different radio standards fulfills the functions of supporting the simultaneous operation of IEEE 802.16m radio devices and other standards located on the same mobile station.

Data Forwarding

The data forwarding unit performs the functions of forwarding when there are relay stations in the line between the base station and the mobile station. The data forwarding unit may interact with other units, such as a resource scheduling and pooling unit and a MAC PDU.

Anti-jamming

The anti-interference unit performs the functions of managing mutual interference between cells / sectors. These features may include:

- Using the capabilities of the MAC level

- Transmission of measurement information and interference estimates as part of MAC signaling information

- Noise reduction due to scheduling and flexible frequency reuse

- Using the capabilities of the PHY level

- Regulation of transmission power

- Randomization

- Noise reduction

- Measurement of interference

- Pre-coding and beamforming of the transmitter

Base station coordination

The base station coordination unit coordinates the actions of several base stations by exchanging information, for example, interference management information. The functions of this unit include providing information exchange, for example, about interference management, between base stations, as part of the signaling information of the core network and the messages of the mobile stations at the MAC level. Such information may include interference characteristics, for example, interference measurements, etc.

Figure 11 shows the user traffic data stream and processing at the base station 14 and the subscriber station 16. The dashed arrows indicate the user graph data stream from the network layer to the physical layer and back. On the transmitting side, the network layer packet is processed by the convergence sublayer, the ARQ function (if used), the fragmentation / packing function, and the function of forming MAC PDUs that are transmitted to the physical layer. On the receiving side, the physical layer SDU is processed by the function of forming MAC PDUs, the fragmentation / packing function, the ARQ function (if used), and the convergence sublevel function to form network layer packets. The solid arrows show the basic control components between the CPS functions and between CPS and PHY, which are associated with the processing of user graph data.

The figure 12 shows the flow of signal information of the control level and processing at the base station 14 and the subscriber station 16. On the transmitting side, dashed arrows indicate the flow of signal information of the control level from the functions of the control level to the functions of the data level and the processing of signal information of the control level of the data level functions to generate corresponding MAC signaling information (eg, MAC control messages, MAC headers / subheadings) for transmission over a wireless link. On the receiving side, the dashed arrows indicate the processing of the MAC signal information received over the air by the data layer functions and the reception of the corresponding signal information of the control level by the functions of the control level. The solid arrows show the basic controls between the CPS functions and between CPS and PHY that are associated with the processing of control level signaling information. The solid arrows between the M_SAP / C_SAP and MAC function blocks indicate the basic control and organization components in the direction of the control and networking system (NCMS) and in the opposite direction. The base components in the M_SAP / C_SAP direction and in the opposite direction determine the network functionality involved, such as the fight against mutual interference between base stations, mobility management within / between the RAT, etc. and management-related functionalities, such as location management, system configuration, etc.

The figure 13 presents the architecture of the basic protocol that defines the support system with many carrier frequencies. The common part of the MAC can control the distribution of the physical layer PHY across multiple frequency channels. Some MAC messages transmitted on one carrier may overlap other carriers as well. Channels can have different bandwidths (for example, 5, 10 and 20 MHz), which can be adjacent to each other, or there can be gaps between them. Channels can have the same or different duplex modes, for example, FDD, TDD, or they can be a combination of bidirectional and broadcast channels only.

The common part of the MAC can support the simultaneous operation of subscriber stations 16 with different capabilities, such as working on only one channel at a time, or working on several channels that can adjoin each other, or there may be gaps between them.

Embodiments of the present invention are described with reference to a MIMO communication system. In a MIMO communication system, packet relay schemes may be implemented that can be used in accordance with the IEEE 802.16 (e) and IEEE 802.11 (n) standards. The packet relay schemes described below can be applied to other wireless communication environments, such as, for example, those operating in accordance with the Third Generation Partnership Project (3GPP) and with 3GPP2 standards.

In the description below, the term "STC code mapping" is used to indicate the mapping of a symbol distribution over antennas. Each symbol in such a card can be replaced by its conjugate value (for example, S1 *), or a rotated symbol (for example, jS1, -S1 and -JS1), or a symbol obtained as a result of pairing and rotation (for example, jS1 *). In some embodiments, mapping also includes assigning signal weights for each antenna.

Multicast technology (one source - many recipients) is widely used for delivery of multimedia content over networks. Multicast services can be expanded using wireless transmission to subscriber stations. In multicast transmission, a wireless communication system transmits circularly data packets to subscriber stations, and each subscriber station receives and processes the same packet stream.

The MBS mode can only be carried out in one direction, namely, only in downlink channels. Subscriber stations that are in active mode, standby mode, or standby mode may be able to receive information flows carried out in multicast (by subscription) or broadcast modes.

Figure 14 is a general diagram of a cellular communication system 1400 comprising a plurality of cells 1405, each of which is served by a respective base station 1410. Base stations 1410 and cells 1405 may be similar to base stations 14 and cells 12 previously described with reference to Figure 1. How and in FIG. 1, in FIG. 14, each cell is divided into sectors 1415, although in other embodiments, division into sectors may be absent. Base stations 1410 provide communication using OFDM modulation with subscriber stations 1425, which may be similar to subscriber stations described previously with reference to FIG. 1, however, in principle, these may be any devices that are capable of communicating with a base station. In this example, subscriber stations 1425 are subscribed to a multicast service (MBS), that is, they can receive an MBS data stream from base stations 1410.

The cellular communication system 1400 comprises an MBS area 1420 in which an MBS service is provided in accordance with some design. In this example, MBS transmissions are single frequency network (SFN) transmissions.

You must understand that the sizes (including the number of cells 1405 and sectors 1415 and the shape and comparative sizes of cells 1405 and sectors 1415) and the shape of the coverage area of the cellular communication system 1400, including the MBS area 1420 shown in FIG. 14, are just an example, and in in other examples, the cellular communication system 1400 may have a different shape and size. For example, the MBS area 1420 may cover the entire coverage area of the cellular communication system 1400 or may include one or more cells 1405. In addition, to the extent that the description of the MBS area 1420 and the MBS schemes used can be applied to individual sectors 1415, the area MBS 1420 may span only one or more sectors 1415.

MBS traffic is transmitted downlink from the base station 1410 to the subscriber station 1425 in DL subframes. More specifically, an MBS schedule is transmitted in a dedicated MBS zone. Figure 15 is a diagram of a DL subframe 1500 comprising an MBS zone 1505 and a unicast zone 1510. In the unicast zone 1510, traffic (not MBS) is transmitted in any suitable manner. The unicast zone 1510 is indicated for the purposes of this example to distinguish it from the MBS zone 1505. However, it should be understood that the unicast zone 1510 can be any zone in which traffic that is not an MBS schedule is transmitted.

The MBS zone contains MBS traffic, including MBS control information in the control subzone 1515 and MBS data in the data subzone 1520, as shown in FIG. 15.

For simplicity, the DL subframe is shown in block form to illustrate all transmission resources occupied by the DL subframe. It should be understood that the transmission resources occupied by the DL subframe may be determined in any suitable manner, depending on the coding / modulation scheme used. For example, in an OFDM scheme, transmission resources allocated to a DL subframe can be defined in the time domain (eg, time intervals for transmitting one symbol) or in the frequency domain (eg, subcarrier frequencies).

In this example, the DL subframe 1500 is determined by OFDM time slots and subcarriers. However, it should be understood that the transmission resources occupied by the DL subframe 1500 may be determined by other parameters. For example, if the allocated frequencies must be fully assigned to the downlink, then the DL subframe 1500 may be uniquely determined by the frequency. In other examples, the DL subframe 1500 may be determined by time (eg, OFDM intervals), subcarriers, spreading sequences, or combinations thereof. In fact, any split gear mode can be used.

Similarly, it should be understood that the MBS zone 1505 and the unicast zone 1510 can be determined using any suitable parameter type. In this example, the transmission resources occupied by the MBS zone 1505 and the unicast zone are determined, like the DL subframe 1500, in OFDM time slots and subcarriers. However, it should be understood that the transmission resources occupied by these zones can also be determined in another way. In addition, these zones need not be determined using the same parameters that are used to define the DL subframe 1500. For example, they can be determined by separate extension sequences used for each zone.

In this example, the DL subframe 1500 comprises an MBS zone 1505 and a unicast zone 1510. They are multiplexed using FDM. However, it should be understood that the MBS zone 1505 may occupy the entire DL subframe.

In this example, zone 1505 MBS is a local zone. That is, it is continuous in the time and frequency domains. However, it should be understood that the MBS zone 1505 may also be a distributed zone that has gaps in either the time domain, the frequency domain, or both. A distributed MBS zone may provide greater frequency diversity for MBS traffic. In particular, the MBS distributed zone can provide greater frequency diversity when there are few sectors involved in SFN transmission.

The configuration of the MBS zone and its location (for example, occupied transmission resources, in this case time and frequency) can be communicated to the subscriber station 1425 in any suitable way. In one embodiment, the configuration of the MBS zone 1505 may be transmitted by the base station. For example, the base station can transmit the configuration and location of the MBS zone in control messages related to broadcast, multicast, or unicast transmission to all subscriber stations or only to those that have subscribed to the MBS service. In another configuration variant, MBS zones 1505 are negotiated well in advance and are not specifically transmitted.

The MBS control information contained in the control subzone 1515 may include indications of the next occurrence of the zone or MBS data, or of the transmission period of the zone or MBS data.

For MBS traffic transmitted over a large network, the multipath channel length may be large. In order to provide MBS traffic transmitted over a large network, an increased cyclic prefix size can be determined. To increase the size of the cyclic prefix in the DL subframe, which is configured to transmit a smaller cyclic prefix, one OFDM symbol is excluded from the DL subframe 1500 containing the MBS zone 1505. After that, the cyclic prefixes of the remaining OFMD symbols are increased to fill the original length of the subframe. It should be understood that although in this embodiment only one OFDM symbol is excluded from the subframe in order to make room for enlarged cyclic prefixes, in other embodiments, several symbols may be excluded.

The channelization and pilot patterns for MBS zone 1505 may be the same for all sectors involved in SFN transmission. In particular, the pilot used for MBS transmission may be a common pilot that is transmitted at the same frequencies in each sector involved in SFN transmissions. For MBS traffic, any suitable pilot arrangement may be used. The pilot arrangement used for MBS traffic may be the same as for the unicast schedule, or they may be different. In this particular embodiment, the pilot arrangement for MBS traffic is similar to the pilot arrangement for a unicast schedule, but with a higher pilot density.

As shown in FIG. 15, MBS control information is contained in MBS zone 1505. Although in this case, the diagram shows that the MBS control information is located in the continuous control MBS subzone 1515 of the MBS zone 1505, it should be understood that the control MBS subzone 1515 may have gaps and be distributed within the MBS zone 1505.

Figure 16 shows a DL subframe 1600 comprising an MBS zone 1605 and a unicast zone 1610 similar to the DL subframe 1500 in Figure 15. MBS zone 1605 also includes an MBS control subzone 1615 and an MBS data subzone 1620. In this embodiment, unicast data is superimposed on the MBS traffic in the MBS zone 1605. In this case, the unicast control information may be contained within the MBS zone 1605. In particular, unicast control information may be superimposed on MBS control information in MBS control subzone 1615. Thus, as shown, the MBS control subzone 1615 may comprise an SFN MBS control area 1625 related to SFN transmission and superimposed unicast control information 1630. The content and format of control messages used in the unicast zone can be used to signal unicast traffic in the MBS zone 1605. It can be used to indicate configurations and / or location of the unicast schedule in the 1605 MBS zone.

As shown in FIG. 15, in general, general MBS control information can be transmitted to all sectors 1415 on the same transmission resources within the MBS zone 1505 using SFN transmissions. If some control information is specific to a particular sector 1415, then this control information may be transmitted to subscriber stations 1425 in sector 1415 in broadcast mode using transmission resources outside of MBS zone 1505.

MBS traffic can be transmitted in three different ways. In the first method, MBS traffic is transmission at the same level. In this case, the same signal is transmitted by each transmitting antenna, and phase and / or gain weights can be used to maximize the input signal power. This method can be specified as a single-level mode.

In the second case, MBS traffic is transmitted at several MIMO levels using spatial multiplexing (SM). This method can be specified as SM mode. In this case, data may be transmitted using one codeword (SCW) or several codewords (MCW). However, in the general case, each sector in the 1420 MBS zone or SFN will transmit all MIMO layers using the same transmission format.

A third method for transmitting MBS traffic involves hierarchical layers. In this hierarchical mode, two or more levels may be transmitted. The first level is the basic level at which data of relatively low quality are transmitted. Data quality can be determined by a number of factors. In one embodiment, data quality refers to the quality of an electronic product that is determined by that data. For example, at a basic level, data corresponding to a multimedia product, such as a low-quality audio, video, or audiovisual product, may be transmitted. For example, low quality data may determine video information with a low bit rate or low resolution.

The second level is the level of quality improvement. At this level, additional information is transmitted that complements the data of poor quality, in the form of improving data, which provide an improvement in the data transmitted at a basic level. Baseline and enhancement level data can be transmitted together as part of the MBS schedule. In this embodiment, additional information may be transmitted, for example, information providing an increase in bitrate or resolution of video materials determined by low quality data transmitted at the first level.

It should be borne in mind that improving data can contain any information that can improve data of poor quality. For example, enhancement data may transmit information that adds an SD effect to video information of the usual 20 format transmitted at a basic level, or may contain information that provides an increase in the bitrate of audio data transmitted at a basic level, or provides a higher resolution of images. Enhancing data can also improve low-quality data by providing other enhancements in addition to low-quality data. For example, enhancement data may provide subtitles for video data transmitted at a basic level, or genre and / or other information related to music recordings transmitted at an advanced level.

In addition, enhancement data can be used not to improve the final electronic product, but to improve the data itself of poor quality, for example, by providing redundancy.

In addition to the second layer, additional quality improvement layers can also be used that provide additional enhancement data to further improve the quality of the data transmitted at the basic level. For example, at a basic level, low-quality data corresponding to the low resolution of video materials may be transmitted, and the improved quality level may contain enhancement data to improve the quality of these videos, and, more specifically, to increase their resolution. The third level may be a second level of quality improvement. This third level can provide additional improvement in low quality data. This can be done by applying additional enhancement data to the result of improving the data of poor quality. For example, enhancement data can provide an increase in the resolution of video materials determined by low quality data, and additional enhancement data can further increase the resolution of video materials. In other embodiments, additional enhancement data can be applied directly to data of poor quality, or to data of poor quality and to the result of increasing their quality by improving data. For example, the third level may contain subtitle data or additional audio data, such as audio tracks with accompaniment in different languages. In this case, data of the third level can be applied to data of poor quality or to the result of their improvement by data of the second level.

In hierarchical mode, regardless of whether or not improving data is transmitted, transmission configurations and the number of levels used can be predefined or can be set selectively. For example, each base station may decide on the number of hierarchical levels to be used, and some additional restrictions may apply. In a non-limiting version of the hierarchical mode, two possible transmission levels can be used: a basic level, as already described, and one level of quality improvement. Sectors in the center of the MBS zone 1420, such as sectors 1415b, can transmit baseline data and quality improvement level data, while sectors near or at the edge of the MBS zone 1420, such as sectors 1415 ₀ , can be limited to transmitting basic data only level.

The transmission format used determines the mode (one level, SM or hierarchical) of the data transmission, as well as the transmission configuration, such as a modulation and coding scheme (MCS), which determines the type of coding used or the code rate and the modulation scheme. In hierarchical mode, the MCS scheme used for MBS transmission may be different for different levels. For example, the base layer may use a more robust MCS scheme to provide reception at subscriber stations 1425 of at least low-level data transmitted at the base layer.

The MCS table may contain transmission formats and any amount of information about the formats used. For the case of the cellular communication system 1400, the transmission format for the MBS schedule may be indicated by an index in the MCS scheme table for MBS. In particular, the MCS MCS schema table for MBS may determine for each MCS index whether the transmission is hierarchical or spatial multiplexing (SM) is used. In addition, the MCS MCS schema table for MBS can determine the different modulation levels and code rates to be used, including modulation and code rates for use at different levels in the case of a hierarchical mode. Table 1 below is an example of an MCS schema table for MBS.

MCS Level Level 1 Level 2 Mode (SM / Hierarchical) Field Modulation Code rate Modulation Code rate one QPSK 1 / 3.2 rep. 000 2 QPSK 1/3 001 3 16 QAM 1/3 010 four 64 QAM 1/3 011 5 QPSK 1/3 QPSK 1/3 N one hundred 6 QPSK 1/3 16QAM 1/3 N 101

7 QPSK 1/3 QPSK 1/3 Sm 110 8 16 QAM 1/3 16 QAM 1/3 Sm 111

Table 1 (example MCS schema table for MBS)

Table 1 contains eight different transmission formats. The MCS level indicates the level of the modulation and coding scheme and can be used as an index identifying a specific transmission format in the table. The Field parameter can also serve this purpose. The first four formats define different modes with one level, which correspond to different levels of modulation and / or code rate. The first format contains QPSK modulation and a 1/3 code rate with two repetitions. The other three formats include QPSK modulation, 16 QAM and 64 QAM, respectively, and a code rate of 1/3. Since these transmission formats all contain only one level, the modulation and code rate characteristics for the second level are not in the table for them.

In the fifth and sixth transmission formats shown in Table 1, a hierarchical mode is used. As already mentioned, in this mode, low-quality data is transmitted at the basic level, while improving data is transmitted at the level of quality improvement. As you can see, two levels can have the same modulation schemes and code rates (although this is not necessary). In particular, in the fifth transmission format shown in Table 1, QPSK modulation and a code rate of 1/3 are used for the base layer and the quality improvement layer. In the sixth transmission format, QPSK modulation is used for the base layer, while 16 QAM modulation (1/3 code rate for both formats) is used for the quality improvement level.

In the seventh and eighth transmission formats indicated in Table 1, the SM mode is used. They use two levels, although the modulation scheme and code rate are the same for both levels.

For the hierarchical mode, the selection of the number of hierarchical levels used may be performed by the base station 1410. The base station 1410 may select the number of hierarchical levels used. In a non-limiting embodiment, the base station 1410 receives feedback information from a subscriber station 1425. As part of the feedback information, any information characterizing transmission conditions can be transmitted. For example, feedback information may characterize the condition or quality of a channel. Or, the feedback information may simply indicate whether the previous transmission was successful or unsuccessful. The feedback information may also include the characteristics of the subscriber station 1425 for receiving data, or about its location, or any other information that may affect the transmission.

To provide the necessary coverage area for the MBS schedule, the base station 1410 may change the transmission format used in the SFN mode, depending on the feedback information for the MBS received from the subscriber stations 1425 with which the base station 1410 communicates.

In general, the feedback information for the MBS received from the subscriber station 1425 is data transmitted at a low rate that indicates the quality of the MBS service. Any suitable feedback scheme may be used, and the method by which the base station 1410 selects a transmission format depends on the type of feedback information received. In one embodiment, the feedback information may be a requested transmission format for MBS traffic. In another embodiment, the feedback information may be a Confirmation / Negative Acknowledgment (ACK / NACK) indicator, where NACK may indicate that the packet error rate for the MBS exceeds a certain threshold value.

In response to such information, the base station 1410 can switch to using only a subgroup of hierarchical levels. In some cases, the transmission format indicated in the MBS control information may not correspond to the actual transmission format used by the base station 1410. For example, the MBS control information may indicate the use of hierarchical levels, however, the base station 1410 may use only the first level. This can happen, for example, if the base station 1410 decided to reduce the number of hierarchical levels used to provide more reliable low-quality data transmission. In this case, although the subscriber stations 1425 that receive MBS traffic will not receive (all) enhancement data, they will still receive low quality data transmitted at a basic level.

It should be understood that the above Table 1 MCS schemes for MCS are presented only for purposes of illustration, which should not be construed as limiting the scope of the invention. In particular, it should be noted that the MCS schema table for the MCS may contain more or less fields / columns to indicate any information related to the transmission formats contained therein. The MCS schema table for MCS may contain more or less transmission formats, depending on the number of such transmission formats available for MBS.

table 2 provides a simpler example MCS schema table for: MCS Level Modulation Code rate Field one 00 2 01 3 10 four eleven

4 Table 2 (one MCS level for

As you can see, in Table 2 there are no two levels for modulation schemes and code rate. This table can be used when only one level mode is used for MBS. In addition, since there is no mode parameter field that defines the mode used for each transmission format specified in the table, Table 2 cannot be used to determine the mode (single level / SM / hierarchical mode).

However, if the information that the MBS schedule should be transmitted using the SM mode is obtained from another source (for example, if this is a known predefined condition for the MBS zone), then Table 2 can still be used to determine the transmission format if the base station has information that for all MBS transmission levels one modulation scheme and a code rate indicated in the table will be used. Similarly, if it is known that MBS transmission should be carried out using a hierarchical mode, then Table 2 can also be useful, provided that for all MBS transmission levels one modulation scheme and code rate indicated in the table will be used, or, in general, if No additional level information required.

Table 3 is an example MCS schema table for MBS for use with hierarchical mode only. MCS Level Level 1 Level 2 Field Modulation Code rate Modulation Code rate

one QPSK 1 / 3.2 rep. QPSK 1 / 3.2 rep. 00 2 QPSK 1/3 QPSK 1/3 01 3 QPSK 1 / 3.2 rep. 16 QAM 1 / 3.2 rep. 10 four QPSK 1/3 16 QAM 1/3 eleven

Table 3 (example MCS schema table for MBS, hierarchical mode)

Table 3 is an example of a table that can be used, for example, in cases where MBS traffic is transmitted using only hierarchical mode and does not contain a mode field. Since each transmission mode shown in Table 3 is implicitly defined as a mode using a hierarchical mode, each transmission mode indicates the modulation scheme and code rate used for several sublevels of the corresponding levels. In this embodiment, two levels are used in each transmission format. It should be understood that more levels may also be used. In addition, if multiple layers are used, not all transmission formats should use all layers.

Table 4 below is an example of an MCS MCS schema table that combines the single-layer transmission formats shown in Table 2 and some of the hierarchical transmission formats of Table 3. Thus, Table 4 defines the transmission formats that define the different modes.

MCS Level Level 1 Level 2 Field Modulation Code rate Modulation Code rate one QPSK 1/3, 2 rep. 000 2 QPSK 1/3 001 3 16 QAM 1/3 010 four 64 QAM 1/3 011 5 QPSK 1/3 QPSK 1/3 one hundred 6 QPSK 1/3 16 QAM 1/3 101 7 Reserve 110 8 Reserve 111

Table 4 (combines different modes)

A similar table can be obtained if the transmission formats include single-layer modes and SM modes. Table 5 below is an example of an MCS MCS schema table that shows transmission formats using single-layer mode and SM modes.

MCS Level Level 1 Level 2 Mode (SM / Hierarchical) Field Modulation Code rate Modulation Code rate one QPSK 1 / 3.2 rep. 000 2 QPSK 1/3 001 3 16 QAM 1/3 010 four 64 QAM 1/3 011 5 QPSK 1/3 QPSK 1/3 Sm one hundred 6 16 QAM 1/3 16 QAM 1/3 Sm 101 7 Reserve 110 8 Reserve 111

Table 5 (combines different modes)

Finally, in the MCS schema table for MBS, transmission formats using one layer, SM, and hierarchical modes can be indicated. Table 6 is an example of such a MCS schema table for MBS. As you can see, Table 6 contains fields for modulation and coding for two levels, the fields of which can take different values if the mode specified for a particular transmission is a hierarchical mode.

MCS Level Level 1 Level 2 Mode (SM / Hierarchical) Field Modulation Code rate Modulation Code rate one QPSK 1 / 3.2 rep. QPSK 1 / 3.2 rep. N 000 2 QPSK 1/3 QPSK 1/3 N 001 3 QPSK 1/3 16QAM 1/3 N 010

four 16 QAM 1/3 011 5 64 QAM 1/3 one hundred 6 QPSK 1/3 QPSK 1/3 Sm 101 7 16 QAM 1/3 16 QAM 1/3 Sm 110 8 Reserve 111

Table 6 (example MCS schema table for MBS)

If there are several MBS transmission networks or territories in which different MBS transmissions are performed in the cellular communication system 1400, then neighboring MBS transmission territories may use non-overlapping MBS zones to transmit the corresponding MBS content. The resources used by the neighboring MBS transmission network can transmit unicast data with less power.

In addition, for sectors 1415 at the edge of the MBS zone, additional resources may be used to transmit MBS traffic. For gradually increasing redundancy, as occurs in HARQ mode when transmitting unicast data, additional information may be transmitted. This information may be transmitted in the same subframe as the initial MBS transmission or in the next subframe. This can be done for several sectors in which SFN is used, or independently by sector.

The above embodiments of the present invention are given only as examples. Specialists in the art can propose various changes and modifications of these specific options without going beyond the scope of the present invention.

Claims (13)

1. A method of transmitting related to the service of group and broadcast information transmission (MBS), when communicating according to the scheme "multiple inputs - multiple outputs" (ΜΙΜΟ), containing stages in which:
a. transmitting the first data at the first level ΜΙΜΟ, the first data being data of poor quality;
b. transmitting the second data at the second level ΜΙΜΟ, the second data being an improvement data providing an improvement in the data of poor quality; and
c. transmitting third data at the third level ΜΙΜΟ, and the third data is additional improving data to further improve data of poor quality,
moreover, the MBS transmission should be determined at the subscriber station based on the result of improving the data of poor quality with improving data if the first and second data are successfully received, and the MBS transmission should be determined at the subscriber station only with poor quality data if the first data is received successfully and the second is not. 2. The method according to claim 1, wherein the first data is transmitted at the first level ΜΙΜΟ using the first encoding scheme, and the second data is transmitted at the second level ΜΙΜΟ using the second encoding scheme, different from the first encoding scheme. 3. The method of claim 2, wherein the first encoding scheme is a QPSK scheme and the second encoding scheme is a 16 QAM scheme. 4. The method of claim 1, wherein further improving the data of poor quality comprises applying said additional improving data to the result of improving the data of poor quality
improving data. 5. A method for performing a transmission related to a group and broadcast information transfer service (MBS) when communicating according to the “multiple inputs - multiple outputs” (ΜΙΜΟ) scheme, comprising the steps of:
a. transmitting the first data at the first level ΜΙΜΟ, the first data being data of poor quality;
b. decide on whether to transmit the second data at the second level ΜΙΜΟ, the second data being an improvement data providing an improvement in low quality data; and
c. decide on whether to transmit third data at the third level ΜΙΜΟ, and the third data is additional improving data, providing additional improvement of low quality data,
moreover, the MBS transmission should be determined at the subscriber station based on the result of improving the data of poor quality with improving data if the first and second data are successfully received, and the MBS transmission should be determined at the subscriber station only with poor quality data if the first data is received successfully and the second is not. 6. The method according to claim 5, further comprising the step of receiving feedback information describing the transmission conditions from the subscriber station, the decision being made as to whether to transmit the second data based on this feedback information. 7. The method of claim 6, wherein said decision is made on whether to transmit third data based on
mentioned feedback information. 8. The method of claim 6, wherein said decision is made on whether to transmit second data based on a geographical location. 9. The method of claim 7, wherein said decision on whether to transmit second data is based on proximity to the edge of the MBS coverage area. 10. A method for transmitting traffic of a group and broadcast information service (MBS) when communicating according to a "multiple inputs - multiple outputs" (ΜΙΜΟ) scheme, comprising:
a. selecting a transmission format for transmitting MBS data from a plurality of available transmission formats, each of which has a transmission mode;
b. transmit MBS traffic using the selected transmission format; and
c. transmitting third data at the third level ΜΙΜΟ, and the third data is additional improving data to further improve data of poor quality,
wherein said plurality of available transmission formats includes at least one transmission format comprising one of a transmission mode at one level, a spatial multiplexing (SM) mode, and a hierarchical mode, and at least another transmission format comprising another one from transmission mode at one level, spatial multiplexing (SM) mode and hierarchical mode. 11. The method of claim 10, wherein said plurality of transmission formats are defined in a modulation and coding scheme (MCS) table for
MBS 12. The method of claim 10, wherein said plurality of transmission formats includes a first transmission format comprising a hierarchical mode. 13. The method according to p. 12, in which the first transmission format further comprises a first modulation and coding scheme for transmitting the first data at the first level and a second modulation and coding scheme for transmitting the second data at the second level, the second data supplementing the first data.

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