Method and apparatus for transmission within a multi-carrier communication system

(54) Title: METHOD AND APPARATUS FOR (57) Summary:

TRANSMISSION WITHIN A MILTI-CARRIER COMMUNICATION SYSTEM (30) Unionist Priority: 07/03/2007 us 11 / 683,030 (73) Owner (s): Motorola, INC.

(72) Inventor (s): Arvind Krishnamoorthy, Brian K. Classon, Kevim L. Baum, Philippe J. Sartori, Robert T. Love, Yakum Sun (74) Attorney (s): Orlando de Souza (86) International Request: pct US2008054678 of 22/02/2008 (87) International Publication: wo 2008 / i09269de 12/09/2008

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METHOD AND APPLIANCE FOR TRANSMISSION WITHIN A SYSTEM OF

MULTI-CARRIER COMMUNICATION

<td colspan="2">TECHNICAL FIELD</td><td rowspan="2">PROVIDED invention</td><td rowspan="2">relates</td><td rowspan="2">generally</td><td rowspan="2">The</td>

<td>THE</td><td>gift</td>

<td>allocation</td><td colspan="2">appeal and,</td><td>in particular,</td><td>to a method</td><td>and</td>

<td>device</td><td>for</td><td>to allocate</td><td>resources and</td><td>schemes</td><td>in</td>

modulation / coding associated with the user.

HISTORY OF THE TECHNIQUE PROVIDED

Many modern orthogonal frequency division (OFDM) multiplexed system proposals include the ability to support frequency selective resource allocation. During the allocation of frequency selective resources, the channel bandwidth is divided into several sub-bands, which can be called resource tiles or blocks. Each resource block includes several adjacent OFDM subcarriers and can span multiple OFDM symbol periods. For example, a resource block size that has been considered in the effort to standardize 3GPP (LTE) long-term evolution is 12 adjacent sub-carriers for 14 OFDM symbol periods. The use of resource blocks allows the allocation of data for a particular user to be made in the resource block having the best channel quality.

However, when a high data rate needs to be supported to / from the user, it may be necessary to allocate multiple resource blocks (over frequency) to the user. This results in the difficulty of how to handle the allocation of multiple resource blocks. In a possible approach, the modulation and coding scheme (MCS) could be chosen independently

2/35 for each of the allocated resource blocks. However, this approach can be inefficient when the set of modulation encoding schemes is limited, as the quality of the best resource block may be much higher than is actually needed to support the highest speed MCS available in the system. Another possible approach is to use a single MCS over all allocated resource blocks, where the code word covers all allocated resource blocks to provide frequency diversity. The problem with this approach is that it may result in a lower data speed or productivity than the first approach. Therefore, there is a need for an improved method and apparatus to allocate resources and associated modulation / encoding schemes to the user.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a block diagram of a communication system.

Figure 2 illustrates the transmission of multiple subcarriers to the communication system of Figure 1.

Figure 3 is an illustration of a resource block for the OFDM system.

Figure 4 describes an exemplary frame structure.

Figure 5 is a block diagram of the equipment that can be used either as a base station or user equipment.

Figure 6 is a flow chart showing the operation of the device of Figure 5 when acting as a base station.

In Figure 7, there is a flow chart showing the operation of the device in Figure 5 while designating a maximum of two PDUs.

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In Figure 8, there is a flow chart showing the operation of the device in Figure 5 when designating a maximum of two PDUs.

Figure 9 is a flow chart showing the operation of the device in Figure 5 when used as a base station.

Figure 10 is a flow chart showing the operation of Figure 5 when used as user equipment. DETAILED DESCRIPTION OF THE DRAWINGS

To meet the need mentioned above, a method and apparatus are provided to indicate to a communication unit a plurality of modulation and coding schemes (MCSs) to be used for the communication. During a first MCS it is determined for the first resource block to be sent to a first remote unit or base station, and a second MCS is determined for a second resource block to be sent to the remote unit or base station. A message is transmitted indicating the first and second MCS and also indicating the first resource block and the second resource block. Finally, a first PDU is transmitted to the remote unit or base station in the first time using the first MCS and the first resource block and a second PDU is transmitted to the remote unit or base station in the first time using the second MCS and the second resource block.

The above technique provides an improved method for determining which resources to allocate to the user, and which modulation / encoding schemes (MCSs) should be used in those resources (for example, for improved link adaptation performance). The above technique takes into account

4/35 accounts for the fact that the set of MCSs available is limited, and that the quality of the channel may be higher in certain features than is necessary to support the higher speed MCS of the set of MCSs available. The provided technique performs resource allocations and MCS selections in such a way as to take advantage of excess signal quality to increase overall data speed when multiple resources (eg multiple resource blocks over frequency) are allocated to the user.

Different sets of resources assigned to the user on the frequency may carry different packet data units (PDUs) for that user. The technique provided also provides signaling methods that reduce the signaling burden to identify the resources and MCSs that must be assigned to the user.

The present invention encompasses a method for indicating to a communication unit a plurality of modulation and coding schemes (MCSs) to be used for communication. The method comprises the steps of determining a first MCS for the first resource block to be sent to a first remote unit or base station, determining a second MCS, different from the first MCS, for a second resource block to be sent to the unit remote or base station, and transmit a message indicating the first and second MCS and also indicating the first resource block and the second resource block. A first PDU is transmitted to the remote unit or base station in a first time using the first MCS and the first resource block, and a second PDU is transmitted to the

5/35 remote unit or base station in the first time using the second MCS and the second resource block.

The present invention additionally encompasses a method comprising the steps of determining a first quality index for the first resource block, determining a relative quality index for at least a second resource block, on which the relative quality index is based the quality of the at least second resource block in relation to a quality of the first resource block, transmit a message indicating the first quality score and the relative quality score, where the message causes the receiver to determine a first modulation and coding scheme for the first resource block and a second modulation and coding scheme for the at least second resource block. In this method, the number of bits used to represent the first quality index may differ from the number of bits used to represent the relative quality index.

The present invention additionally encompasses an apparatus comprising a set of logic circuits for performing the steps of determining a first MCS for the first block of resources to be sent to a first remote unit or base station and determining a second MCS, which differs from the first MCS, for a second block of resources to be sent to the remote unit or base station. A transmitter is provided to transmit a message indicating the first and second MCS and also indicating the first resource block and the second resource block, transmitting a first PDU to the remote unit

6/35 or base station in a first time using the first MCS and the first resource block, and transmit a second PDU to the remote unit or base station in the first time using the second MCS and the second resource block.

The present invention additionally encompasses an apparatus comprising a set of logic circuits to perform the steps of determining a first quality index for the first resource block, determining a relative quality index for at least a second resource block, in which the Relative quality index is based on the quantity of at least the second resource block in relation to a quality of the first resource block. A transmitter is provided to transmit a message indicating the first quality score and the relative quality score at which the message causes a receiver to determine a first modulation and coding scheme for the first resource block and a second modulation scheme / encoding for at least the second resource block.

For the description below, a packet data unit (PDU) can be considered as a particular block of data over which a single modulation and coding scheme (MCS) (for example, QPSK modulation with R = 1/2 coding turbo) is present. The PDU may contain one or more code words, or a portion of a single code word, and multiple PDUs having the same MCS may be present.

Moving now to the drawings, where equal numbers designate equal components, Figure 1 is a block diagram of the communication system 100. The communication system

Communication 100 comprises one or more cells 105 (only one shown) each having a base transceiver station (BTS, or base station) 104 in communication with a plurality of mobile or remote units 101-103. (Remote units 101-103 may also be referred to as communication units, User Equipment (UE), mobile, or simply users, while base station 101 may also be referred to as a communication unit or simply Nõ-B). In the preferred version of the present invention, the communication system 100 uses an Orthogonal Frequency Division Multiplexed (OFDM - Orthogonal Frequency Division Multiplexed) or multi-carrier architecture. The use of transmission diversity may also be employed. When using transmission diversity, base station 104 employs multiple antennas (not shown in Figure 1) to transmit multiple data streams across multiple OFDM subcarriers to one or more receiving devices 101-103. Base station 104 will also be able to use spreading techniques such as multiport CDMA (MC-CDMA), multiport direct sequence CDMA (MC-DS-CDMA), Code Division and Orthogonal Frequency Multiplexing (OFCDM) with uni- or two-dimensional scattering, or it may be based on the simplest time and / or frequency multiplexing / multiple access techniques, or a combination of these various techniques.

Base station 101 comprises a transmitter and receiver that serve a number of remote units within a sector. As it is known in technology, the physical area

The entire 8/35 served by the communication network may be divided into cells, and each cell may comprise one or more sectors. Base station 101 may employ multiple transmission antennas and / or multiple reception antennas to serve each sector to provide several advanced communication modes (eg adaptive beam formation, transmit / receive diversity, Space Division Multiple Access (SDMA) ) transmission / reception, multiple stream transmission / reception, etc.).

As will be recognized by someone of ordinary skill in the technology, during the operation of an OFDM system, multiple sub-carriers (for example, 300 sub-carriers, as considered for an LTE 3GPP mode) are used to transmit broadband data. This is illustrated in Figure 2. As shown in Figure 2, the broadband channel is divided into many narrow frequency bands (sub-carriers) 201, with data being transmitted in parallel on sub-carriers 201. In addition to OFDM, communication system 100 uses Adaptive Modulation and Coding (AMC - Adaptive Modulation and Coding). With AMC, the modulation and encoding format of a stream of data transmitted to a particular receiver is modified based on an expected received signal quality (at the receiver) or link quality for the particular frame being transmitted.

The modulation and coding scheme may change on a frame-by-frame basis (where the frame could be defined as one or more OFDM symbol periods) to keep up with variations in channel quality that occur in mobile communication systems. So blocks of us

High quality resources or links are typically referred to as higher order modulation rates and / or higher channel coding rates with the modulation order and / or the code rate decreasing with the decrease in quality. For those receivers who experience high quality, modulation schemes like 15 QAM or 256 WAM are used, while for those who experience low quality, modulation schemes like BPSK or QPSK are used. The selected modulation and encoding can only roughly match the current received signal quality for reasons such as delay in measuring channel quality or errors, delay or errors in reporting channel quality, efforts to measure or predict current interference and future, and efforts to measure or predict the future channel.

Multiple encoding rates may be available for each modulation scheme to provide finer AMC granularity, to allow for a closer match between the quality and characteristics of the transmitted signal (for example, R = 1/4, and% for QPSK;

R = 1/2 and R = 2/3 for 16 QAM, etc.). Note that adaptive modulation and coding (AMC) can be done in the time dimension (for example, updating the modulation / coding every Ni OFDM symbol periods) or in the frequency dimension (for example, updating the modification / coding every N_sand sub-carriers) or a combination of the two. The combination of a particular modulation scheme (for example, 16-QAM) with a particular encoding scheme (for example, R = 1/2 turbo encoding) can be referred to as an MCS. Each MCS that is

10/35 used in a system may have an associated data rate value that is preferably normalized to units of information bits per symbol. For example, the MCS of R = 1/2 QPSK can provide one bit of information per symbol (charges, such as back bits, if present, could also be factored into the rate value, if desired). For convenience, the fee amount for an MCS will be referred to as MCSR. An example set of MCSs is shown in Table 1.

Table 1

<td>MCS (or MCS index)</td><td>Modulation</td><td>Rate of code</td><td>MCSR</td>

<td> 1</td><td>BPSK</td><td>K</td><td> 0,5</td>

<td> 2</td><td>QPSK</td><td></td><td> 1</td>

<td> 3</td><td>QPSK</td><td></td><td> 1,5</td>

<td> 4</td><td>16-QAM</td><td> 1/2</td><td> 2</td>

<td> 5</td><td>64-QAM</td><td></td><td> 3</td>

<td> 6</td><td>64-QAM</td><td></td><td> 4,5</td>

<td> 7</td><td>64-QAM</td><td>1 (no encoded)</td><td> 6</td>

Figure 3 illustrates the concept of Resource Blocks (RB Resource Blocks). A resource block type consists of one or more subcarriers occupying one or more OFDM symbols. For example, a resource block may be a tile of 12 subcarriers per 14 OFDM symbols. Not all modulation symbols within an RB may be available for the transmission of data load, as some of the modulation symbols may be used for other purposes such as control channels or reference signals (for example, pilot). Furthermore, not all

11/35 RB symbols need to be assigned to a single user. For example, some of the symbols could be assigned to a first user and other symbols could be assigned to a second user.

Figure 4 illustrates an exemplary frame structure using the resource block structure of Figure 3. As shown in Figure 4, the total bandwidth is divided into several resource blocks (such as 401 and 403). As shown in detail for resource block 041, each resource block can have the structure of Figure 3. To simplify signaling and reduce signaling expenses, the resource block is preferably defined as the atomic resource allocation that the user can obtain in a single frame. One possibility is to assign all resource blocks to a user and a Packet Data Unit (PDU -Packet Data Unit). Another possibility is to designate multiple users on the board by giving them different resource blocks. For example, one user may be allocated resource block 401, and another user may be allocated resource block 403. Yet another possibility is to allocate the entire frame to a user, but share the resource blocks between one or more PDUs. For example, resource block 401 may be allocated to user 1 for PDU1, and resource block 402 may be allocated to user 2 for PDU2. Other possibilities also exist.

Allocating one or more PDUs to the same user in the same frame with each PDU being assigned its own MCS can have significant performance benefits. The PDU encoded with an MCS will preferably comprise at least one error correction code word, such as the

12/35 turbo coded codeword. These code words may be called forward error correction (FEC) code words. In some cases, the PDU encoded with an MCS may comprise more than one FEC codeword, for example, when the PDU is greater than the maximum number of bits of information that can be included within a single FEC codeword. The code word or code words associated with the PDU can be communicated on the same ARQ channel or the same hybrid ARQ channel (HARQ), or it can be communicated on separate ARQ or HARQ channels. It is also possible that spreading with or without multi-code transmission can be used either in addition to or instead of the FEC for one or more MCS levels. Like FEC, spreading introduces memory through transmitted data.

Figure 5 is a block diagram of equipment 500 that can be used either as a base station or user equipment. As shown, equipment 500 comprises logic circuitry 501, transmission circuitry 502, reception circuitry 503, and storage (database) 504. Storage 504 serves to store index values ​​for various schematics. modulation and coding or quality levels. For example, an index of 1 could correspond to QPSK 1/8, an index of 2 to QPSK \ í, etc. In another version, if the exponential effective SNR mapping methodology is used, the beta values ​​and E limits_s/ N₀corresponding static values ​​can be stored at 504.

The logic circuitry 501 preferably comprises a microprocessor controller, such as, but

13/35 without limiting it, a Freescale PowerPC microprocessor. In the preferred version of the present invention, the logic circuitry 501 serves as a means to control the equipment 500, and as a means to analyze the content of the received message, and a means to determine the modulation and coding schemes for various resource blocks . The transmission and receiving circuitry 502-503 are common circuits known in technology for communication using well-known OFDM protocols, and serve as a means for transmitting and receiving messages.

Figure 6 is a flow chart showing the operation of the Figure 5 device when it acts as a base station. In particular, the logic flow in Figure 6 illustrates an example of implementing such a process in which more than one PDU, each with its own MCS, is assigned to a single user. The logic starts at step 601, in which a set of RBs (for example, all RBs across the channel bandwidth, or a subset of the RBs) are classified by logic circuit set 501 in order of descending quality so that the first rated RB in the set is the RB where the best radio performance (for example, highest link quality, highest MCS, signal-to-noise ratio (SNR), ETC.) can be expected (for example, based on signal quality measurements, or channel quality feedback information), and the bottom ranked RB of the set is the one where the worst performance is expected. For example, channel quality information may be received at receiver 503. In step 603, a first allocation RB, S, is initiated by the set of

14/35 logic circuits 501 when initializing S for the first RB (the best) of the set. In step 605, MCS_ifi, the best sustainable MCS over S is determined by logic circuitry 501. An example criterion for the best sustainable MCS is an MCS that if designated provides the highest possible data rate (for example, highest MCSR) for a acceptable probability of successful transmission. In step 607, the best remaining RB of the set (that is, excluding the RB that was selected in step 603) is selected by logic circuit set 501. In step 609, an evaluation is performed by the logic circuitry 501 to determine whether MCS_ifi could still be supported by an allocation covering both S and this best remaining RB (that is, a resource allocation that includes both the highest rated RB and the second highest rated RB). If positive, then the

<td>set</td><td>of circuits</td><td>logical</td><td> 501</td><td>adds</td><td colspan="2">the best RB</td>

<td>remaining</td><td>to the S in step</td><td>619, ec</td><td colspan="2">&gt; logical flow</td><td>to be continued</td><td>for</td>

<td>the stage</td><td>515 where the</td><td>set</td><td>in</td><td>circuits</td><td>logical</td><td> 501</td>

determines whether there are any remaining RBs left in the pool that have not yet been considered. If the determination is positive at step 615, the process returns to step 607 followed by step 609 again.

If the result of step 609 is negative, then the total allocation S over which MCS_ifl can be sustained has been determined and can be assigned together with MCS_ifi for the user in step 611 (or stored in storage 504 until the entire process flow is complete, for later use). The designation process involves designating a PDU to be transmitted with the 502 transmitter in

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RBs in allocation with MCS_ifi.

Continuing, the logic flow continues to step 513 where the logic circuitry 501 resets S to the best remaining RB of the set as determined in step 607. Also, in step 607, a new MCS value_sei is determined by the logic circuitry 501 for the newly defined S. The logic flow then proceeds to step 615 where the logic circuitry 501 determines whether there is any remaining RB left from the set that has not yet been considered. If the determination of step 615 is positive, then the logic flow returns to step 607. If the determination of step 607 is negative, then all RBs in the set have been considered and the current allocation S and MCS_ifi can be assigned by the very logical logic circuitry circ 501 to the user together with all the allocations previously determined. Note that each of the S allocations has a different MCS. Also note that RBs that comprise a particular allocation based on this process are not necessarily contiguous.

The process in Figure 6 could potentially assign multiple PDUs to a single user. However, it is expected that allowing only two PDUs to be assigned to a user will provide most of the performance benefit of the technique provided while simplifying the process and potentially reducing signaling expenses.

In Figure 7, there is a flow chart showing the operation of the device in Figure 5 when designating a maximum of two PDUs. The logic starts at step 7 01, in which the RBs of the set are classified by the set of circuits

16/35 logic 501 in descending order of quality so that the first RB is the RB where the best radio performance can be expected, and the last RB is the one where the worst performance is expected. Then, in step 703, the first allocation of RB, S, is initialized by the logic circuitry 501 when initializing S to the first RB (the best). In step 705, MCS_ifi, the best sustainable MCS over S is determined by the logic circuitry 501. In step 707, the best remaining RB is selected by the logic circuitry 501. In step 709, the logic circuitry 501 assesses whether MCS_ifi can be sustained over an RB allocation that spans S and this best remaining RB. In the set notation, this is the Su {RB} set. If it is positive, the best remaining RB is added by the logic circuitry 501 to S in step 715. The logic flow then continues in step 717 where the logic circuitry 501 determines whether there are still RBs remaining in the set to process: if positive , the logic flow returns to step 707. If there are no more RBs remaining, the logic flow continues at step 719 where logic circuitry 501 allocates the first PDU over S (possibly all available RBs) and instructs transmitter 501 to transmit using MCS_ifi. If, on the other hand, in step 709, it is determined that MCS_ifi cannot be sustained over an RB allocation that spans S and the best remaining RB, the logic circuitry 501 evaluates MCS_ifi, the best sustainable MCS over all remaining RBs in the array does not depart from S in step 711. In step 713, logic circuitry 501 designates the first PDU for S to be transmitted with MCS_ifie

17/35 a second PDU to be transmitted over all remaining RBs in the set (which are not part of S) to be transmitted with MCS_rest ·

Another process for assigning a maximum of two PDUs to the same user in the same frame is shown in Figure 8. The process described in Figure 8 could potentially provide link efficiency mediated by increased bandwidth or data rate when compared to the process in Figure 7, at the cost of greater complexity in the process. The logic begins at step 8 01, where a set of RBs are classified by the logic circuitry 501 in descending order of quality so that the first RB is the RB where the best radio performance can be expected, and the last RB is one where the worst performance is expected. In step 803, an index is initialized by logic circuitry 501. In step 805, two MCSs are determined by logic circuitry 501: MCS_Best (i), the best sustainable MCS in i best RB, and MCS_rest (i), the best sustainable MCS in the remaining Ni RBs. The rate values ​​associated with MCS_best (i) and MCS_rest (i) are denoted as MCSR_besyou) ^and MCSR_rest (i), respectively. In step 807, another value, MCSR_eg(i), which represents the equivalent or net MCSR over the entire set of RGBs is calculated by the logic circuitry 501 and is preferably calculated based on the following equation:

MCSReg (i) = i * MCSR_best (i) + (N- 1) * MCSR_rest (i) ·

In step 809, logic circuitry 501 increments i by 1. In step 811, logic circuitry 501 compares i against N + l, and the logic flow returns to step 805. If i = N + l, j , the index that maximized

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MCSReq is determined by the logic circuitry 501 in step 813. In step 815, a first PDU is allocated by the logic circuitry 501 for the best RBs and the logic circuitry 501 will instruct transmitter 502 to transmit with MCS_best (j) θ a second PDU for the remaining RBs (MCS_rest(j)).

In an additional aspect, energy redistribution can optionally be employed to further improve system performance. For example, when two MCSs were designated using the algorithm described in Figure 8, the excess energy in both PDU1 (with MCS_X) as in PDU2 (with MCS₂) can be collected for each PDU, just enough energy is allocated to support the selected MCS. The remaining energy can then be redistributed: a policy may be to redistribute energy to add RBs initially allocated to PDU2, the PDU with the lowest MCSR, to PDU1, the PDU with the best MCS. The RBs, when ordered from best to worst, are then taken sequentially to improve the MCS in the RB considered by some amount. Alternatively, the RBs can be selected in a way that the energy redistribution will maximize the link efficiency (on average over the two PDUs, like the equivalent or net MCSR). Power redistribution is particularly useful in a multi-user context where users are likely to be staggered at their best RBs and when the resource blocks or shelves allocated to the second PDU are likely to be used for collision resolution.

Any of the techniques described above can be applied either on the uplink or on the link

19/35 descending, regardless of the duplexing method (for example, TDD or FDD). Furthermore, several modifications can be made to the processes while remaining within the scope of the technique provided, or different processes could be used, while remaining within the scope of the technique provided, which provide the same effect of allocating multiple MCS over frequency to a single user while takes advantage of excess signal quality in one or more RBs to expand the number of RBs that can effectively support / use a particular MCS.

An additional aspect of the technique provided involves improved signaling / texting. The following versions will be described for the case where the user transmits channel quality information to a base station to assist the base station in determining the sets of RBs and their associated MCSs to use when transmitting to the user on the downlink, but the technique provided is also applicable to other scenarios (for example, role of the downlink and inverted uplink, role of the base station and the inverted user, etc.).

The use of different modulation and coding schemes for each resource block set requires messages to identify each resource block set and the modulation and coding scheme used in each of the resource block sets. Providing this information increases the cost of signaling, and to be as efficient as possible, the amount of feedback needs to be reduced.

To address this issue, the user's equipment can determine the channel quality information (CQI)

20/35 which includes, for example, the set of resource blocks it recommends to be included in each allocation along with the channel quality indicator (for example, SNR, SINR, or MCS index) for each of the recommended allocations. The user equipment can then feed back the channel quality information (CQI) of each set of resource blocks in a single message so that the appropriate MCS can be chosen for each of the set of resource blocks. For example, when two sets of resource blocks are being used, the user's equipment will be determining the first quality information and a corresponding first index for the first set of resource blocks and determining the second quality information for the second set of resources. resource blocks. Quality index values ​​for the first and second quality information will be determined and a single message will be transmitted from the user's equipment indicating the first and second qualities. The first and second qualities can be represented individually, or by linking the value of one quality index to the other (for example, by the first quality index and the difference between the second index and the first quality index, respectively). More particularly, for the linked case, the second quality information can be relative to the first quality information and can be communicated by a relative quality index as the difference in quality index between the first and the second quality index. The relative quality score allows the receiver to determine the second quality score when both the

21/35 first quality score as the relative quality score are known. In one example, a single bit indicator can be used to signal the difference in the quality index such that if the bit value is 0, then the MCS index₂ is the MCSi index minus 1 and if the bit value is 1, then the MCS index₂ is the index of CMS1 minus 2. Additionally, the message may comprise an indication of which resource blocks should use the first MCS (or which resource blocks are associated with the first quality value) and which resource blocks should use the second MCS (or which resource blocks

<td>They are</td><td>associated with</td><td>second</td><td>value</td><td>Of Quality).</td><td>An</td>

<td colspan="2">map representation</td><td>bit</td><td>may</td><td>be used</td><td>for</td>

<td>take along</td><td>efficiently</td><td colspan="2">this information.</td><td>A message</td><td>CQI</td>

<td colspan="4">copy may be as follows:</td><td></td><td></td>

<td> 1.</td><td>. MCSi</td><td></td><td></td><td></td><td></td>

<td> 2 ,</td><td>. MCS₂</td><td></td><td></td><td></td><td></td>

<td> 3 .</td><td>, A message from</td><td>map of</td><td>bits of</td><td>N bits, where</td><td>Huh</td>

the number of resource blocks available. The bit value of 1 in position k would mean that MCSi is associated with the number RB k, while the bit value of 0 in position k would mean that MCS₂ is associated with the number RB k.

Note that with this type of CQI message, the user's equipment is indicating to the base station that when the base station subsequently transmits to the user's equipment, the first PDU can be supported with the best sustainable MCSi on all RBs with the value bit 1, and a second PDU can be supported with the most sustainable MCS2 of all RBs with the value

22/35 bit 0, where each PDU is separately modulated and encoded. Please also note that if the channel quality varies over time, a new CQI message, based on the current channel conditions, may need to be transmitted periodically by the user's equipment to enable quality changes to be tracked.

The current RBs and MCS used for the transmission may be the same or different than those in which the CQI is reported. Furthermore, the CQI message may not be all transmitted in a single frame. For example, a frame can contain either MCSi or MCS₂ or part of the bitmap. As another example, one frame may contain MCSx and part of the bitmap, and another frame may contain MCS2 and part of the bitmap. In another example, the CQI message in some frames may be configured to provide a differential update to the information that was transmitted in a previous frame or frames.

MCSi and MCS₂ can be represented by an MCS index. To further reduce feedback, MCS₂ can be sent in relation to MCSi: in other words, the index corresponding to MCS2 can be sent as the difference between the index corresponding to MCSi_X and the index corresponding to MCS₂. For example, the difference in values ​​represented by the corresponding bits in the message may be fixed, or it could be dependent on the value of MCSi, or other factors. In general, to reduce expenditure, MCS₂ it may be dependent on any information known to both the base station and the remote unit. Some examples of this other information could be the value of MCS1, or a

23/35 average SNR per band. For example, the user's equipment can feed back a medium channel quality indicator (for example, SNR) in addition to other CQI information. In an example of using the average CQI per band, for an average SNR per band greater than 10 dB, the value of 1 (respectively 0) for MCS₂ may mean that for the second set of resource blocks, the transmitter must use the MCS index corresponding to the index

MCS for

MCSi minus one (minus two, respectively). For example, for an average SNR per band greater than 10 dB, the value of 1 (0 respectively) for MCS₂ it may mean that for the second set of resource blocks, the transmitter must use the MCS index corresponding to the MCS index for MCS1 minus two (minus three, respectively). Alternatively, instead of sending values ​​from the MCS index, the user's equipment can transmit any quality information from the radio link that can be used to determine the MCS, such as the SNR value, an effective SNR value, the information value mutual, or the data rate value. For example, depending on the average SNR value per b walk and a single bit being used for MCS₂, the value of 1 may correspond to a reduction of 1 bit per symbol of spectral efficiency, while the value of 0 may correspond to a reduction of 0.5 bit per symbol of spectral efficiency. Alternatively, MCS₂ it could also always be selected as a known value (for example, QPSK R 1/3). In another example, to reduce signaling, the MCSs and the set of RBs selected for PDU1 and PDU2 can be decided such that there is a finite set of

24/35 possible differences between the MCSi and MCS indices₂ . This further reduces the number of bits to encode the difference between the MCS index₂ and the MCSi index.

After the base station determines which resource blocks and MCSs to actually assign to the user's equipment (for the user's equipment to receive information from the base station), the designation information can be communicated to the user's equipment using a control channel on the downlink. To limit the size of the control channel message transmitted by the base station to the remote unit, several possibilities are listed below for the designation message format:

EXAMPLE 1: FIXED SIZE DESIGNATION, ONE HARQ CHANNEL

For some versions, the size of the control message may be fixed for each user's equipment. In that case, the following fields may be included in the fixed size designation message:

1. HARQ channel ID;

2. User ID;

3. The set of resource blocks (RB1) used for PDU1;

4. The modulation and coding scheme for RB1;

5. The set of resource blocks (RB2) used for PDU2; and

6. The modulation and coding scheme for RB2 (MCS2).

In this example, the same HARQ channel is used for both PDU1 and PDU2, with the consequence that if only one of the two PDUs transmitted cannot be decoded,

25/35 both will have to be retransmitted. The user ID is an uniquely assigned identifier so that it can be determined to which user equipment this resource designation message applies. The MCS can be signaled in a similar way to the CQI information. In particular, MCS₂can be indicated with an index related to MCSi with a similar process to that described above to save signaling bits. Similarly, the two sets of resource blocks can be indicated with a bitmap field similar to the CQI bitmap field. It is implicitly indicated that a separate packet data unit (PDU) will then be transmitted over each set of resource blocks for the same period of time, and that each PDU will be modulated and encoded separately. The user ID can be a MAC ID.

EXAMPLE 2: DESIGNATION OF FIXED SIZE, TWO CHANNELS HARQ

In example 1, when sending a unique HARQ channel ID, failure in one of the two transmitted PDUs will trigger the retransmission of the two transmitted PDUs, even if one was received correctly. To avoid this problem, the base station can send two HARQ channel IDs in the assignment message (one for PDU1 and one for PDU2). In addition, the HARQ channel ID for PDU2 can be implicitly flagged: for example, if HARQ_ID1 is used for PDU1, HARQ_ID2 can be automatically set to HARQ_ID1 module of the number of HARQ channels.

EXAMPLE 3: JOINT DESIGNATION, ONE HARQ CHANNEL

Since more than one user can be staggered in a frame, the base station can take advantage of this multi-user situation by jointly encoding all messages

26/35 designation in a single designation message. For example, the base station may be able to transmit.

1. A list of user IDs

2. The following fields, M times (where M is the number of user equipment staggered in the same table):

The. HARQ channel ID

B. MCS1

ç. MCS2

3. A bitmap region with the following fields, N times (where N is the number of available block resources):

The. Short user equipment ID

B. One bit, where 0 means that this particular resource block is for the first set of resource blocks (corresponding to PDU1), and 1 means that this particular resource block is for the second set of resource blocks (corresponding to PDU2 ).

The short UE ID is a unique identifier for a particular user ID and is valid for this frame only. It can be derived from the order in which user IDs M are transmitted: for example, the user whose user ID is listed first would be designated the short ID of value 0 (in decimal), the second the short ID of value 1, etc. Alternatively, the short ID can be explicitly flagged when the list of user IDs is transmitted, and can be valid for more than one frame.

EXAMPLE 4: JOINT DESIGNATION, TWO CHANNELS HARQ

This version is similar to the previous one, but two HARQ channel IDs are signaled, one for the first PDU and one

27/35 for the second PDU.

EXAMPLE 5: JOINT DESIGNATION WITH VARIABLE CONTROL DESIGNATION SIZE

With Example 3, the size of the control designation message is fixed. While this is appropriate if all users transmit two PDUs, it could result in unnecessary resource expenditure if some users transmit only one PDU. The solution in this case is to send the information to PDU2 only when necessary. The format of the resource designation message can be as follows:

1. A list of user IDs

2. The following fields, M times (where M is the number of user equipment staggered in the same table):

The. A bit to indicate whether the designation is for one or two PDUs

B. HARQ channel ID

ç. MCS1

<td colspan="5">d. MCS2 (if two designations)</td><td rowspan="2">the fields</td>

<td>3. An</td><td>region</td><td>in</td><td>maps of</td><td>bits with</td>

<td>following, N</td><td>times</td><td>(in</td><td>that N is the</td><td>number of</td><td>blocks of</td>

<td colspan="2">available resources)</td><td></td><td></td><td></td><td></td>

<td>The. ID</td><td colspan="2">equipment</td><td>of user</td><td>I enjoy</td><td></td>

B. If only one designation, that's all. If more than one designation, a bit, where 0 means that this particular resource block is for the first set of resource blocks (corresponding to PDU1), and 1 means that this particular resource block is for the second set of blocks of resources (corresponding to PDU2).

Of course, it is possible to flag two channel IDs

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When to broadcast

HARQ if necessary.

A packet data unit (PDU) will then be communicated over each set of resource blocks for the same period of time. Each PDU will be separately modulated and coded.

The system can support transmission by multiple antennas, such as transmission diversity, Multiple Input, Multiple Output (MIMO) open loop, closed loop formation, or Multiple Input, Multiple Output (MIMO) closed loop. The format of multiple antennas may include weightings of possibly complex and different transmission antennas applied to each resource block. A transmission of multiple antennas may include multiple spatial streams in a resource block that was intended for a single remote unit, where in the resource block different antenna weights are used to transmit each spatial flow. These spatial flows may either be intended to have their own PDU or intended to have a single PDU for all flows, or some combination. With multi-stream transmission, there is at least one resource block in which two or more flows are transmitted by spatial multiplexing.

multiple antennas are used for multiple streams, each stream can be configured to have two PDUs each with an MCS and a set of RB. The transmission format of multiple antennas may be communicated in addition to the designation information for the PDUs (MCS_X, set RB1, MCS₂, set RB2). Such communication may include an indication of the transmission weight of the antenna as through a

29/35 code book. If multiple spatial streams are present and multiple PDUs are desired, multiple sets of PDUl and PDU2 (with MCS_X and associated RBls) may be transmitted. For example, flow 1 may have PDU1 and PDU2, while flow 2 may have PDU3 and PDU4. To reduce signaling, RB1 = RB3 and RB2-RB4. Alternatively, stream 2 may have only a single MCS in its designated RBs, which may be part or all of RBl and RB2.

To reduce signaling when multiple antenna techniques are supported, signaling can be configured to support either Multiple Input, Multiple Output (MIMO) multi-stream or two or more PDUs in non-overlapping sets of RBs. This reconfigurable signaling can be especially efficient if the multi-stream case has two intended PDUs and two PDUs (with different RBs and MCS) are also supported. In this case, the system may have flow 1 with PDUl / MCS_χ/ RBl and PDU2 / MCS₂/ RB2, or flow 1 PDUl / MCSi and flow 2 PDU2 / MCS₂. For the multi-flow case, RBl and RB2 overlap in at least one RB, and RBl may be equal to RB2. Signaling can be configured in a number of ways, including:

- A bit that indicates Multiple Input, Multiple Output (MIMO) of multi-flow or not.

An entry in a table indexed by a multi-bit multi-antenna field.

- A codebook entry having a certain value to indicate 2 PDUs in a single flow.

- Two codebook entries having the same value that indicates 2 PDUs in a single flow.

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- A transmission matrix is ​​sent that is level 1.

- The remote unit blindly decodes the control channel in search of each of the two possible formats. The formats may differ physically either in the number of bits of information, encoding rate, or seeded CRC.

In addition to the general configuration, different bit fields can be either retained or remapped. For example, both modes may require an MCS field for each PDU. If for the multi-stream configuration only a single RB allocation is present (both flows use the same set of RBs) then in the case of two PDUs and a single flow a second RB allocation may be provided, or the RB allocation may be assumed as the inverse of the RB allocation of the first PDU in all or part of the band.

The number of streams that can be supported with multi-stream transmission is not constant. For example, because of changes in the space environment, two flows may no longer be supported. When a flow is finished, the current HARQ process in that flow can be mapped over one of the remaining flows using a different set of RBs. One of the algorithms described above can be used to determine the MCS in the two sets of RBs. When a flow is added, signaling for the second HARQ channel can be used.

EXAMPLE 7: FIXED DESIGNATION MESSAGE WITH ENERGY ALLOCATION

To further improve system performance, it is possible to allocate energy on a RB basis. In that case, the message in example 1 can be reused. In addition, a bitmap message with the allocation of

31/35 energy per RB can be transmitted. To limit the feedback, the energy indication can be coded differently, with the reference energy value known by both the transmitter and the receiver.

Figure 9 is a flow chart showing the operation of equipment 500 when used as a base station. During operation, a CQI message is received by the receiver 503 of the user's equipment (step 901). As discussed above, the CQI message will comprise information about the quality of any signal received by a number of resource blocks being used. Thus, in step 901 at least the first quality information is received for a first set of resource blocks, and the second / relative quality information is received for a second set of resource blocks (in one of the many examples outlined above) . The first and second sets of resource blocks may simply comprise a resource block. In addition, as discussed above, each resource block comprises a contiguous set of sub-carriers.

In step 903, logic circuitry 501 determines a first MCS for a first set of resource blocks and a second MCS for a second set of resource blocks. As someone of ordinary skill in the technology will recognize, the MCS chosen for each set of resource blocks is related to at least the quality perceived on this set of resource blocks by the user's equipment. The logic circuitry then accesses storage 504 and determines a first MCS index for the first circuitry

32/35 resource blocks and a second MCS index for the second set of resource blocks (step 905). They can be represented as a first and a second bit, the first bit indicating a set of resource blocks in which the first resource block is allocated, and the second bit indicating a second set of resource blocks in which the second block of resources is allocated. resources are allocated.

In step 907, logic circuitry 501 instructs transmitter 501 to transmit a message to the user's equipment indicating the first and second MCS and also indicating the first and second resource blocks. The first and second MCS are represented by the first and second MCS index. Alternatively, the first and second MCS can be represented by the first MCS index and the difference between the first MCS index and the second MCS index, respectively. Alternatively, the MCS can be signaled by any of the examples given above, finally, in step 909, transmitter 502 transmits a first PDU to the user's equipment in a first time using the first MCS and the first set of resource blocks and additionally transmits a second PDU to the user's equipment in the first time using the second MCS and the second set of resource blocks.

It should be noted that, although the logic flow above was directed towards a base station transmitting to a mobile station, or remote unit, someone of ordinary skill in the technology will recognize that the logic flow above may be implemented within a remote unit that is transmitting data to the base station

33/35 using multiple resource blocks. It should also be noted that when energy allocation is taking place, a first energy allocation for the first resource block and a second energy allocation for the second resource block may be determined by logic circuitry 501 and a second message may be be transmitted by transmitter 502 indicating the first and second allocations of energy. Furthermore, when the need to send the first and second PDUs within a single Multiple Input, Multiple Output (MIMO) stream is determined, the first Multiple Input, Multiple Output codebook index (MIMO) may be transmitted within of the first message. A multi-antenna field may additionally be transmitted within the first message, where the multi-antenna field indicates that the transmission is not a multi-stream transmission.

When HARQ is being used, transmitter 502 will also be able to transmit a single HARQ channel indicator for the first PDU sent in the first resource block and the second PDU sent in the second resource block. Alternatively, a first HARQ channel indicator for the first PDU sent in the first resource block and a second HARQ channel indicator for the second PDU sent in the second resource block can be transmitted.

Figure 10 is a flow chart showing the operation of equipment 500 when it is being used as user equipment. The logic flow begins at step 1001 where the set of logic circuits determines the first quality information for a first set of resource blocks and a second quality information for a

34/35 second set of resource blocks. Each resource block set can comprise only a single resource block. In step 1003 the logic circuitry accesses storage 504 and determines a first quality index and a second quality index. The quality score reflects a quality value in some predetermined format (for example, a set of one or more bits that represent a numeric quality value directly or indirectly, one or more bits that serve as a flag within a predefined table (for example, example, the MCS index in Table 1, a SINR table, etc.). The second quality index can be represented either directly, or as a relative quality index or different from the first quality index, so that the second quality can be referred to in the denoted as a second / relative quality. The quality and / or index information is preferably based on at least one of SNR, effective SNR, SINR, effective SINR, mutual information, MCS, or data speed, or may comprise other quality information. Note that the expense with feedback can be reduced if the relative quality is used as the number of bits used to represent the first quality index may differ from the number of bits used to represent the relative quality index. For example, a plurality of bits can be used to represent the first quality index with good precision, and the relative quality index can be represented with a smaller number of bits (as little as 1 bit) to reduce spending, especially when the quality of the second block of resources is expected to be

35/35 correlated or close to that of the first block.

The logic circuitry 501 then instructs transmitter 502 to transmit a message indicating the first quality and the relative quality information (step 1005). As already discussed, the first quality and the relative quality are represented by the first quality index, and a relative index, respectively. The message causes the receiver to determine the modulation and coding schemes for the first resource block and the second resource block.

Finally, in step 1007, data is received about the first and the second set of resource blocks. As discussed above, the data for each set of resource blocks will have a modulation and coding scheme based on the quality of each set of resource blocks.

Although the technique provided has been shown and described particularly with reference to a particular environment, it will be understood by those skilled in the technology that various changes in form and details can be made in it without deviating from the spirit and scope of the technique provided. For example, in a communication system that uses Multiple Input, Multiple Output (MIMO - Multiple-Input-Multiple-Output), the signaling used to signal two PDUs can be reused, at least in part. For example, if the first and second codebook indexes are identical, then it could mean that two PDUs are sent in a single stream. The MCSs for flow one could be used for PDU1. These changes are intended to fall within the scope of the following claims.

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