RU2575013C2 - Systems and methods for transmission diversity for discrete fourier transform precoded channels - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: invention can be used in transmission systems which combine the advantages of DFT precoding and transmission diversity coding for PUCCH transmission. In one aspect, the invention provides an improved transmission diversity coding method and apparatus for DFTS-OFDM PUCCH with minimal impact on multiplexing capacity. In one embodiment, the improved transmission diversity method and apparatus are capable of employing frequency-domain separation for payload signals.

EFFECT: high throughput of transmission channels.

20 cl, 3 tbl, 10 dwg

Description

Cross reference to related application

This application claims the priority of provisional patent application US No. 61373531, filed August 13, 2010.

FIELD OF THE INVENTION

The invention relates to transmit diversity for precoded by discrete Fourier transform (DFT) channels.

State of the art

The Long Term Evolution (LTE) standard uses orthogonal frequency division multiplexing (OFDM) in the downlink and enhanced OFDM discrete Fourier transform (DFT) (DFTS-OFDM) in the uplink. DFTS-OFDM enables flexible bandwidth assignment and orthogonal multiple access not only in the time domain, but also in the frequency domain. Thus, the LTE uplink scheme is also sometimes referred to as single-carrier FDMA (SC-FDMA). In the time domain of the downlink and uplink transmissions, LTEs are organized into 10 ms radio frames, with each radio frame consisting of ten subframes of equal size with a length T _subframe = 1 ms. Resource assignment in LTE is usually described in terms of resource blocks, where the resource block corresponds to one slot (0.5 ms) (i.e., there are two slots per subframe) in the time domain and 12 adjacent subcarriers in the frequency domain.

In order to support the transmission of the downlink and uplink transport channels, some uplink layer 1 and uplink layer 2 (L1 / L2) control signaling is used. The uplink L1 / L2 control signaling includes: (a) a hybrid automatic repeat request (HARQ) acknowledgment (ACK / NACK) for received downlink data; (b) channel status reports related to the conditions of the downlink channel, wherein these reports can be used by the base station in scheduling data transmission in the downlink; and (c) scheduling requests indicating that the mobile terminal (also known as "user equipment (UE)") needs uplink resources for transmitting uplink data. For example, after receiving downlink data in a subframe from the base station, the UE attempts to decode the data and reports to the base station whether the decoding was successful (ACK) or not (NACK). In the event of an unsuccessful decoding attempt, the base station may retransmit erroneous data.

The UE must transmit the uplink L1 / L2 control signaling regardless of whether or not the UE has any uplink transport channel (UL-SCH) data for transmission, and thus, whether or not assigned UE any uplink resources for transmitting UL-SCH data. Therefore, two different methods are used to transmit the uplink L1 / L2 control signaling, depending on whether or not the UE has been assigned an uplink resource for transmitting UL-SCH data.

In the case where the UE does not have a valid scheduling permission — that is, no resources have been allocated for UL-SCH in the current subframe — a separate physical channel, a physical uplink control channel (PUCCH), is used to transmit the uplink L1 / L2 control signaling communication. Otherwise, the uplink L1 / L2 control signaling is multiplexed with UL-SCH coded on the physical uplink shared channel (PUSCH).

More specifically, if the UE has not been assigned an uplink resource for data transmission, L1 / L2 control information (eg, channel status reports, HARQ acknowledgments, and scheduling requests) is transmitted in uplink resources (resource blocks) specifically assigned for information uplink L1 / L2 control, by PUCCH. These resources are located at the borders of the full available bandwidth of the cell. Each such resource consists of 12 “subcarriers” (one resource block) within each of the two slots of the uplink subframe.

Version-8 LTE (Rel-8) has recently been standardized. LTE Rel-8 supports bandwidths up to 20 MHz. The Third Generation Partnership Project (3GPP) initiated work on LTE Version-10 (Rel-10). One part of LTE Rel-10 is designed to support bandwidths greater than 20 MHz. One important requirement imposed on LTE Rel-10 is to ensure backward compatibility with LTE Rel-8. It should also include spectral compatibility. Which should result in that the LTE Rel-10 carrier, wider than 20 MHz, should appear as a number of LTE carriers for the terminal version of LTE Rel-8. Each such carrier may be referred to as a composite carrier (CC). In particular, for initial LTE Rel-10 deployments, it may be expected that there will be fewer terminals supporting LTE Rel-10 compared to numerous terminals of previous LTE versions. Therefore, it is necessary to guarantee the effective use of the wide carrier for legacy terminals, i.e. the ability to implement carriers where legacy terminals can be scheduled in all parts of the LTE Rel-10 broadband carrier. A direct way to get this is by carrier aggregation (CA). CA implies that the LTE Rel-10 terminal can receive multiple CC carriers, where the CC carriers have, or at least have, the ability to have the same structure as the Rel-8 carrier.

CA PUCCH is based on DFTS-OFDM for a UE supporting more than 4 ACK / NACK bits. Multiple ACK / NACK bits (may also include scheduling request (SR) bits) are encoded to form 48 encoded bits. The 48 encoded bits are then scrambled using cell-specific (and possibly DFTS-OFDM character dependent) sequences. The first 24 bits are transmitted inside the first slot, and the other 24 bits are transmitted inside the second slot. 24 bits per interval are converted to 12 QPSK symbols, expanded by five DFTS-OFDM symbols, pre-encoded by DFT and transmitted within one resource block (bandwidth) and five DFTS-OFDM symbols (time). The extension sequence is special for the UE and provides the ability to multiplex up to five users within the same resource block. A demodulation reference signal is also transmitted in each slot. The reference signal comprises a reference sequence. The “reference sequence” referred to herein may represent any information transmitted by a transmitting device to enable or otherwise facilitate demodulation, by a receiving device, of data associated with the reference sequence (eg, data transmitted with the reference sequence). For example, in specific embodiments, the reference sequence may be a CAZAC cyclic shifted sequence (eg, computer-optimized sequences in 3GPP TS 36.211). To further improve orthogonality among the reference signals, an orthogonal coverage code of two lengths may be applied to the reference signals.

In the ongoing development of the LTE system, additional transmit antennas are introduced in the UE to improve transmission performance. There is therefore a need to design transmission methods and devices that combine the benefits of precoding by DFT and transmit diversity coding for PUCCH transmission (including CA PUCCH transmission).

Disclosure of invention

In one aspect, specific embodiments of the disclosed solution provide a transmission method and apparatus that combines the benefits of precoding by DFT and transmit diversity coding for PUCCH transmission. For example, specific embodiments provide a method and apparatus for improved transmit diversity coding for a DFTS-OFDM PUCCH with minimal impact on multiplexing capability. In some embodiments, the enhanced transmission diversity method and apparatus is capable of performing frequency domain separation for payload signals, as well as orthogonal time domain expansion and / or phase shift separation of the sequence.

In one embodiment, a transmit diversity coding method for DFT-encoded channels (e.g., DFTS-OFDM PUCCH) includes generating a data symbol block and transforming a data symbol block to generate a first transformed symbol block and a second transformed symbol block . The first antenna of the mobile terminal is used to transmit, during the interval of the subframe of the radio frame and using only the first set of subcarriers, the first block of converted symbols. The first antenna is also used to transmit the first reference sequence during the same interval. The second antenna of the mobile terminal is used to transmit, during the same interval and using only the second set of subcarriers, a second block of converted symbols. A second antenna is also used to transmit the second reference sequence during the same interval. In order to enhance signal diversity, the first set of subcarriers is orthogonal with the second set of subcarriers. Additionally, the first reference sequence and the second reference sequence may be transmitted using a third set of subcarriers, which comprises a first set of subcarriers and a second set of subcarriers.

In some embodiments, the method also includes generating a second data symbol block and converting a second data symbol block to generate a third transformed symbol block and a fourth transformed symbol block. In these embodiments, the method also includes the steps of: (i) using the first antenna to transmit the third block of converted symbols and the first reference sequence during the second subframe interval, and (ii) using the second antenna to transmit during the second interval the fourth block of converted characters and the second reference sequence. A third converted symbol block may be transmitted using the fourth set of subcarriers, and a fourth converted symbol block may be transmitted using the fifth set of subcarriers, which is orthogonal with the fourth set of subcarriers. In some embodiments, the first and fifth sets of subcarriers consist only of subcarriers with even indices, and the second and fourth sets of subcarriers consist of only subcarriers with odd indices. In other embodiments, the first and fifth sets of subcarriers consist of only subcarriers with odd indices, and the second and fourth sets of subcarriers consist of only subcarriers with even indices.

In some embodiments, the first reference sequence may be orthogonal to the second reference sequence. For example, the first reference sequence may be a cyclic shift of the second reference sequence.

In some embodiments, the step of converting the data symbol block includes the steps of: dividing the data symbol block into at least a first subunit and a second subunit; applying a discrete Fourier transform (DFT) to the first subblock to generate a first block of transformed symbols; and applying a discrete Fourier transform (DFT) to the second subblock to generate a second block of transformed symbols.

In a particular embodiment, a data symbol block consists of twelve data symbols. In this particular embodiment, the step of converting the block of twelve data symbols may include the steps of: dividing the block of twelve symbols into a first sub-block of six symbols and a second sub-block of six symbols; applying a six-DFT to the first sub-block of six characters to generate a first block of transformed characters; and applying a six-DFT to a second sub-block of six symbols to generate a second block of transformed symbols.

In some embodiments, the step of transmitting the first transformed symbol block includes the steps of mapping each symbol within the first transformed symbol block to a particular subcarrier within the first set of subcarriers and applying the inverse fast Fourier transform (IFFT) to the first transformed symbol block. Similarly, the step of transmitting the second block of converted symbols may include the steps of mapping each symbol within the second block of converted symbols to a particular subcarrier within the second set of subcarriers and applying IFFT to the second block of converted symbols.

In one embodiment, a transmit diversity apparatus for pre-coded by Discrete Fourier Transform (DFT) channels includes a first antenna, a second antenna, and a data processor coupled to the first antenna and the second antenna. The data processor is configured to: (a) generate a data symbol block from a set of message bits, (b) convert a data symbol block to generate a first transformed symbol block and a second transformed symbol block; (c) use the first antenna to transmit the first block of transformed symbols and the first reference sequence during the interval of the subframe of the radio frame; and (d) use a second antenna to transmit during the same interval a second block of converted symbols and a second reference sequence. The data processor may further be configured such that (i) the first block of converted symbols is transmitted using the first set of subcarriers, (ii) the second block of converted symbols is transmitted using the second set of subcarriers that is orthogonal with the first set of subcarriers, and (iii) the first reference the sequence and the second reference sequence are transmitted using a third set of subcarriers, which contains a first set of subcarriers and a second set of subcarriers.

In another aspect, specific embodiments of the disclosed solution provide a mobile terminal comprising any of the transmit diversity devices described herein for precoded using Discrete Fourier Transform (DFT) channels.

The above and other aspects and embodiments are described below with reference to the accompanying drawings.

Brief Description of the Drawings

The accompanying drawings, which are contained herein and form part of the description, illustrate various embodiments of the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the art to make and use the invention. In the drawings, like reference numerals show identical or functionally similar elements.

1 illustrates a specific embodiment of a wireless communication system that supports transmit diversity coding for PUCCH transmissions.

2 is a flowchart illustrating processing for coding transmit diversity of a DFTS-OFDM PUCCH channel.

3A, 3B, 4A, and 4B illustrate various subcarrier mappings according to particular embodiments.

5 illustrates data summarizing the performance of a transmission diversity method according to particular embodiments.

FIG. 6 is a flowchart illustrating illustrative processing for implementing some of the steps shown in FIG. 2.

7 is a block diagram of a specific embodiment of a device for coding transmit diversity DFTS-OFDM PUCCH.

FIG. 8 is a block diagram of a DFT module that can be used in specific embodiments of the device shown in FIG. 7.

Fig.9 is a block diagram of an alternative embodiment of the device shown in Fig.7.

10 is a block diagram of a mobile terminal.

The implementation of the invention

Referring now to FIG. 1, FIG. 1 illustrates a mobile terminal 102 having multiple antennas (eg, antenna 111 and antenna 112) and communicating wirelessly with network 110. Specific embodiments of mobile terminal 102 provide enhanced transmit diversity coding processing for DFTS- OFDM PUCCH.

, согласно

, где

и последовательность скремблирования

задается посредством раздела 7.2 из 3GPP TS 36.211. Генератор последовательности скремблирования может, например, инициализироваться с помощью

в начале каждого подкадра.Referring now to FIG. 2, FIG. 2 is a flowchart illustrating an example of such processing 200 that can be performed by specific embodiments of mobile devices 102. Processing 200 assumes that the mobile terminal 102 includes only two antennas: an antenna 111 and antenna 112, but the described solution is not limited to two antennas, since more than two antennas can be used. Processing 200 may begin at block 202, where the medium access control (MAC) layer of the mobile terminal 102 generates message bits (e.g., control information such as ACK / NACK bits, ACK / NACK bits plus a scheduling request bit, etc. .). At step 204, the message bits are encoded into a block of B bits (for example, message bits can be encoded to form a block 48 of encoded bits). At step 206, a block of encoded bits is scrambled. In some embodiments, a block of coded bits may be scrambled using a cell-specific (and possibly dependent on DFTS-OFDM symbols) sequence to generate a block B (e.g., B = 48) of scrambled bits

according to

where

and scrambling sequence

defined by section 7.2 of 3GPP TS 36.211. The scrambling sequence generator may, for example, be initialized with

at the beginning of each subframe.

At 208, a data symbol set is generated from a block of scrambled bits. For example, in step 208, a first subset of a block of scrambled bits is used (e.g., 24 of 48 bits) to generate a first block of N data symbols (e.g., 12 data symbols), and a second subset of a block of scrambled bits is used (e.g., the other 24 of 48 bits ) to generate a second block of N data symbols. In one embodiment, at block 208, the block of scrambled bits can QPSK be modulated to generate two blocks of complex-valued modulation symbols: d (0), ..., d (N-1) and d (N), ..., d (2N-1).

At step 210, the data symbol set is divided into two blocks: a first data symbol block (e.g., d (0), ..., d (N-1)) and a second data symbol block (e.g., d (N), ... , d (2N-1)). The first block will be transmitted during the first subframe interval and the second block will be transmitted during the second subframe interval.

At step 212, the first block of data symbols is converted to generate DFT-encoded data (for example, in some embodiments, prior to converting the block of data symbols, each data symbol is multiplied by a value (w (i))). In specific embodiments, the first block of data symbols is converted to generate a first block of converted data symbols and a second block of converted data symbols.

At step 214, the antenna 111 of the mobile terminal 102 and the first set of subcarriers are used during the first subframe interval to transmit the first block of transformed data symbols. At step 215, the antenna 111 is used during the first subframe interval to transmit the first reference sequence. At step 216, the antenna 112 of the mobile terminal 102 and the second set of subcarriers are used during the first subframe interval to transmit a second block of transformed data symbols. At step 217, the antenna 112 is used during the first subframe interval to transmit the second reference sequence.

Preferably, the first set of subcarriers is orthogonal with the second set of subcarriers. This is illustrated in FIG. 3A. As shown in FIG. 3A, subcarriers with even indices (i.e., f0, f2, ..., f10) are used to transmit the first block of transformed data symbols, and subcarriers with odd indices are set to zero, and subcarriers with odd indices (i.e. f1, f3, ..., f11) are used to transmit the second block of converted data symbols, and subcarriers with even indices are set to zero (in the example, antenna port 0 corresponds to antenna 111 and antenna port 1 corresponds to antenna 112 )

This provides the functionality of dividing the frequency domain for payload signals (i.e., first and second blocks of transformed data symbols) and dividing the orthogonal expansion of the time domain and / or dividing the phase shift of the sequence. At steps 215 and 217, reference sequences may be transmitted using all of the twelve available subcarriers, in which case the first reference sequence should be orthogonal with the second reference sequence. In an alternative embodiment, the reference sequences need not be orthogonal. In such embodiments, it will be preferable to transmit the first reference sequences using a set of subcarriers and to transmit the second reference sequences using a set of subcarriers that are orthogonal with the subcarriers used to transmit the first reference sequence.

At step 218, a second block of data symbols is converted to generate DFT encoded data. For example, a second block of data symbols is converted to generate a third block of converted data symbols and a fourth block of converted data symbols. At step 220, the antenna 111 and the third set of subcarriers are used during the second subframe interval to transmit the third block of converted data symbols. At step 221, the antenna 111 is used during the second subframe interval to transmit the first reference sequence. At step 222, the antenna 112 and the fourth set of subcarriers are used during the second subframe interval to transmit the fourth block of transformed data symbols. At step 223, the antenna 112 is used during the second subframe interval to transmit the second reference sequence.

Preferably, the third set of subcarriers is orthogonal with the fourth set of subcarriers. This is illustrated in FIG. 3B. 3B, subcarriers with even indices (i.e., f0, f2, ..., f10) are used to transmit a third block of transformed data symbols, and subcarriers with odd indices are set to zero, and subcarriers with odd indices (i.e., f1, f3, ..., f11) are used to transmit the fourth block of transformed data symbols, and subcarriers with even indices are set to zero. This provides the functionality of dividing the frequency domain for payload signals (i.e., the third and fourth blocks of converted data symbols) and dividing the orthogonal expansion of the time domain and / or dividing the phase shift of the sequence. At steps 221 and 223, reference sequences may be transmitted using all of the twelve available subcarriers. In this case, the first reference sequence should be orthogonal with the second reference sequence.

In another embodiment, to provide even more uniform spatial diversity for all signals, a cyclic frequency offset for different symbols can be introduced, as illustrated in FIGS. 4A, B. As shown in these figures, only subcarriers with even indices (i.e. .f0, f2, ..., f10) are used to transmit the first and fourth blocks of transformed data symbols, while this data is transmitted via antenna ports 0 and 1, respectively, and only subcarriers with odd indices (i.e. f1, f3, .. ., f11) are used to transmit the second and third blocks of the converted data symbols, while this data is transmitted via the antenna ports 0 and 1, respectively.

The above transmission diversity scheme for DFTS-OFDM PUCCH provides significant link performance enhancements. The required operational SNR for these different schemes is determined based on the following performance requirements:

Frequency (PUCCH DTX → ACK bits) = $$\frac{\#(l\mathrm{about}\mathrm{well}ns{e}^{}b\mathrm{and}t{s}^{}ACK)}{\#(PUCC{H}^{}DTX)}\le {10}^{-2}$$

Pr (NAK or DTX bits → ACK bits) ≤ 10 ^-3

Pr (ACK bits → NAK or DTX bits) ≤ 10 ^-2

The link simulations are set so that the Frequency (PUCCH DTX → ACK bits) = 10 ^-2 . The working SNR is taken as the larger of the relationships required to achieve Pr (ACK bits → NAK or DTX bits) = 10 ^-2 and Pr (NAK or DTX bits → ACK bits) = 10 ^-3 . The performance of the transmission diversity scheme is summarized in FIG. You may notice that with two antenna ports, gain in communication line performance of about 2-2.5 dB can be obtained. Transmission diversity with three or four antenna ports may offer additional link performance enhancements.

Referring now to FIG. 6, FIG. 6 illustrates (a) illustrative steps 602-606 that may be performed in processing step 212 of processing 200, and (b) illustrative steps 608-610 that could be performed in implementing step 214 of processing 200. At 602, the first block M of data symbols is divided into two equally sized subblocks: a first subblock of M / 2 data symbols and a second subblock of M / 2 data symbols. At 604, an M / 2 size DFT is applied to the first sub-block of data symbols to generate a first block of transformed data symbols. Similarly, in step 606, an M / 2 DFT is applied to the second sub-block of data symbols to generate a second block of transformed data symbols. At 608, each data symbol within the first block of transformed data symbols is mapped to a particular subcarrier within the first set of subcarriers. At 610, an inverse fast Fourier transform (IFFT) is applied to the first block of converted data symbols.

Referring now to FIG. 7, FIG. 7 illustrates a transmission diversity coding apparatus 700 for a DFTS-OFDM PUCCH, according to one embodiment.

) от уровня управления доступом к среде передачи (MAC) (например, биты HARQ ACK/NACK) и применять кодировщик 702 для кодирования битов сообщения в блок битов

согласно разделу 5.2.2.6.4 из 3GPP TS 36.212, где

(например, биты могут кодироваться, чтобы формировать блок из 48 кодированных битов).As shown in FIG. 7, device 700 may receive message bits (indicated by

) from the medium access control (MAC) level (for example, HARQ ACK / NACK bits) and use the encoder 702 to encode the message bits into a block of bits

according to section 5.2.2.6.4 of 3GPP TS 36.212, where

(for example, bits may be encoded to form a block of 48 encoded bits).

) и бита запроса планирования (например, бита

). Бит запроса планирования должен быть установлен на 1, чтобы запрашивать планирование, и 0 в противном случае. В еще другом варианте осуществления биты, соответствующие обратной связи HARQ могут получаться посредством логической операции AND нескольких индивидуальных битов обратной связи HARQ. Этот вариант осуществления соответствует частичному связыванию, где множественные биты обратной связи HARQ комбинируются с использованием логического AND и только один бит передается в расчете на связку.In one embodiment, these message bits may consist of HARQ ACK / NACK bits. In another embodiment, the message bits may consist of HARQ ACK / NACK bits (e.g., a bit

) and the scheduling request bit (e.g. bit

) The scheduling request bit must be set to 1 to request scheduling, and 0 otherwise. In yet another embodiment, bits corresponding to HARQ feedback may be obtained by logical operation AND of several individual HARQ feedback bits. This embodiment corresponds to partial linking, where multiple HARQ feedback bits are combined using a logical AND and only one bit is transmitted per link.

. Скремблер может использовать специальную для ячейки (и возможно зависящую от символов DFTS-OFDM) последовательность, чтобы генерировать блок B скремблированных битов

согласно

, где

и последовательность скремблирования

задается посредством раздела 7.2 из 3GPP TS 36.211. Генератор последовательности скремблирования может, например, инициализироваться с помощью

в начале каждого подкадра.Apparatus 700 includes a scrambler 704 for scrambling a block of encoded bits

. The scrambler may use a cell-specific (and possibly DFTS-OFDM character dependent) sequence to generate block B of scrambled bits

according to

where

and scrambling sequence

defined by section 7.2 of 3GPP TS 36.211. The scrambling sequence generator may, for example, be initialized with

at the beginning of each subframe.

и второй подблок

. Первый подблок повторяется

раз и второй подблок повторяется

раз. Повторенная последовательность кодированных битов затем скремблируется посредством последовательности кода скремблирования с помощью способа инициализации, раскрытого выше. Устройство 700 также включает в себя генератор 706 символов, который принимает кодированные и скремблированные биты, использует первый набор этих битов (например, 24 из 48 битов), чтобы генерировать первый блок N символов 791 данных (например, 12 символов данных), и использует другие биты (например, другие 24 из 48 битов), чтобы генерировать второй блок N символов 792 данных. Например, генератор 706 символов может быть модулятором, который осуществляет QPSK модуляцию битов, чтобы генерировать блок комплексно-значных символов данных:

, которые могут разделяться на два блока комплексно-значных символов модуляции: первый блок

и второй блок

.In one embodiment, illustrated in Fig.7, the output from the encoder 702 can be divided into two subunits: the first subunit

and second subunit

. The first sub block is repeated

once and the second sub-block is repeated

time. The repeated sequence of encoded bits is then scrambled by a sequence of scrambling code using the initialization method disclosed above. Apparatus 700 also includes a symbol generator 706 that receives coded and scrambled bits, uses a first set of these bits (e.g., 24 of 48 bits) to generate a first block of N data symbols 791 (e.g., 12 data symbols), and uses other bits (for example, the other 24 of 48 bits) to generate a second block of N data symbols 792. For example, symbol generator 706 may be a modulator that performs QPSK modulation of bits to generate a block of complex-valued data symbols:

that can be divided into two blocks of complex-valued modulation symbols: the first block

and second block

.

, тем самым формируя, в целом, блок комплексно-значных символов данных

согласно:As shown in FIG. 7, for each of the first and second data symbol blocks, the data symbol block is expanded with an orthogonal sequence

, thereby forming, as a whole, a block of complex-valued data symbols

according to:

Where

и

. Для укороченного DFT-S-OFDM PUCCH

и

.For normal DFT-S-OFDM PUCCH

and

. For shortened DFT-S-OFDM PUCCH

and

.

задается в таблицах I и II ниже.Sequence

defined in tables I and II below.

для

.Table I
Orthogonal sequences

for

. Sequence index

Orthogonal sequences

0

one

2

3

four

для

.Table II
Orthogonal sequences

for

. Sequence index

Orthogonal sequences

0

one

2

3

разделяется на

блоков, где

. В показанном примере количество блоков равняется 10 и каждый блок соответствует одному символу SC-FDMA. Например, первый блок состоит из

, второй блок состоит из

, и десятый блок состоит из

.Block of complex-valued data characters

divided into

blocks where

. In the example shown, the number of blocks is 10 and each block corresponds to one SC-FDMA symbol. For example, the first block consists of

The second block consists of

, and the tenth block consists of

.

In the embodiment shown, five of ten data symbol blocks are processed by a set of DFT transforms 708 and an IFFT transform set 710, wherein said IFFT transform set consists of a first subset of IFFT transforms 711 and a second subset of IFFT transforms 712. The other five data symbol blocks are processed by a set DFT 718 transforms and IFFT 720 transform set, wherein said IFFT transform set consists of a first subset of IFFT transforms 721 and a second subset of transform IFFT 722. Data processed by DFT transforms 708 and IFFT transforms 710 are transmitted in a first subframe interval, and data processed by DFT transforms 718 and IFFT 720 transforms are transmitted in a second subframe interval.

. В некотором варианте осуществления предварительное кодирование посредством преобразования, применяемое посредством преобразований DFT, применяется согласно:Each DFT in sets 708 and 718 is pre-encoded by converting one of the above data symbol sets. For example, the DFT 708a will pre-encode by converting a data symbol block

. In some embodiment, transform precoding applied by DFT transforms is applied according to:

if

if

, где p=0, …, P-1 и P равняется количеству передающих антенн (в показанном варианте осуществления P=2, но P может быть большим, чем 2). p-ый блок комплексно-значных символов

передается на антенном порте p. В нашем примере антенный порт 0 соответствует антенне 111 и антенный порт 1 соответствует антенне 112. Из вышеописанного вычисления можно видеть, что p-ый блок может иметь ненулевые значения при индексах

и нули при всех других индексах. Это иллюстрируется для случая P=2 на фиг.3A и 3B.giving the result P blocks of complex-valued characters

, where p = 0, ..., P-1 and P is equal to the number of transmitting antennas (in the shown embodiment, P = 2, but P may be greater than 2). p-th block of complex-valued characters

transmitted at antenna port p. In our example, antenna port 0 corresponds to antenna 111 and antenna port 1 corresponds to antenna 112. From the above calculation, it can be seen that the pth block can have nonzero values at the indices

and zeros for all other indices. This is illustrated for the case P = 2 in FIGS. 3A and 3B.

и второй блок преобразованных символов

. Как описано выше, первый блок преобразованных символов

имеет ненулевые значения при индексах [0, 2, 4,...] и нули при всех других индексах, тогда как второй блок преобразованных символов

имеет ненулевые значения при индексах [1, 3, 5, ….] и нули при всех других индексах.As an example, DFT 708a will generate two blocks of converted data symbols: the first block of converted symbols

and the second block of converted characters

. As described above, the first block of converted characters

has nonzero values at indices [0, 2, 4, ...] and zeros at all other indices, while the second block of converted characters

has nonzero values at the indices [1, 3, 5, ....] and zeros at all other indices.

Referring now to FIG. 8, FIG. 8 illustrates an illustrative embodiment of a DFT 708a. As shown, the DFT 708a includes two 6 point DFT transforms: DFT 802 and DFT 804. As further shown, the input to the DFT 802 is y (0), y (2), y (4), y (6), y (8), y (10). DFT 802 converts this input in a standard way to generate the first block of six converted characters z (0), z (2), z (4), z (6), z (8), z (10). This first block of six converted characters, together with six 0 for filling, are provided in the twelve consecutive inputs of IFFT 711a, as shown. Similarly, input to the DFT 804 is y (1), y (3), y (5), y (7), y (9), y (11). DFT 804 converts this input in a standard way to generate a second block of six converted characters z (1), z (3), z (5), z (7), z (9), z (11). This second block of six converted characters together with six 0 for filling are provided in the twelve consecutive inputs of IFFT 712a, as shown.

IFFT terminal 711a is connected via standard transmission components to antenna port 0 and IFFT 712a is connected via standard transmission components to antenna port 1, so that the first and second converted symbol blocks are transmitted via antennas 111 and 112, respectively, during the first subframe interval. As described above, the first set of subcarriers will be used to transmit the first block of converted symbols, and the second set of subcarriers will be used to transmit the second block of converted symbols, where the first set of subcarriers is orthogonal with the second set of subcarriers (see, for example, FIG. 3A) .

In another embodiment, in order to allow cyclic frequency offset per SC-FDMA symbol, the transform precoding procedure described above can be modified so that transform precoding used by DFT transforms is applied according to:

if

if

Where

, где

. p-ый блок комплексно-значных символов

должен передаваться на антенном порте p. Иллюстрация циклического частотного смещения в расчете на символ SC-FDMA для случая P=2 дается на фиг.4A, B. Шаг циклического частотного смещения

может также быть большим, чем 1. В общем, расширенное предварительное кодирование посредством преобразования задается посредствомAs with the other described precoding procedure through conversion, this procedure yields P blocks of complex-valued characters

where

. p-th block of complex-valued characters

must be transmitted on the antenna port p. An illustration of the cyclic frequency bias per SC-FDMA symbol for the case P = 2 is given in FIGS. 4A, B. The cyclic frequency bias step

may also be larger than 1. In general, advanced precoding by conversion is specified by

if

if

A slightly different display is

if

if

which leads to the same subcarrier mapping of each Pth SC-FDMA symbol.

Demodulation Reference

As shown in FIG. 1, since there are P transmit antennas, P different reference sequences can be used to generate demodulation reference signals. In the example shown, P = 2, thus, two reference sequences are used: the first reference sequence (RS1) and the second reference sequence (RS2). RS1 is transmitted using antenna port 0 and RS2 is transmitted using antenna port 1. Each RS can be transmitted once or twice during the interval, depending on whether the normal or extended cyclic prefix (CP) subframes are used. In the example shown, normal CP subframes are used. The same demodulation reference signal generation is used for PUCCH format 2 except that the orthogonal sequences are specified in Table III below:

для DFT-S-OFDM PUCCH.Table III
Orthogonal sequences

for DFT-S-OFDM PUCCH. Sequence index

Normal cyclic prefix Extended cyclic prefix 0 [+1 +1] [one] one [+1 -1] Not applicable

и стандартной установкой

в подкадрах нормального CP имеется 12 доступных опорных последовательностей. Количества оборудований UE, которые могут мультиплексироваться на одном и том же ресурсном блоке, - это 5, 5, 4 и 3 для P=1, 2, 3 и 4 соответственно. С

и стандартной установкой

в подкадрах расширенного CP имеется 6 доступных опорных последовательностей. Количества оборудований UE, которые могут мультиплексироваться на одном и том же RB, - это 5, 3, 2 и 1 для P=1, 2, 3 и 4 соответственно.FROM

and standard installation

there are 12 available reference sequences in the normal CP subframes. The number of UE equipments that can be multiplexed on the same resource block is 5, 5, 4, and 3 for P = 1, 2, 3, and 4, respectively. FROM

and standard installation

the extended CP subframes have 6 available reference sequences. The number of UE equipments that can be multiplexed on the same RB is 5, 3, 2, and 1 for P = 1, 2, 3, and 4, respectively.

. Подходящие последовательности являются последовательностями CASAC длины

или компьютерно-оптимизированными последовательностями. Из одной базовой последовательности дополнительные ортогональные последовательности могут выводиться посредством циклического сдвига базовой последовательности, как описано в 3GPP TS 36.211, "Physical Channel and Modulation". Для нормального CP с

RS в расчете на интервал может применяться расширение блока временной области, чтобы увеличивать количество доступных последовательностей RS или альтернативно, чтобы увеличивать расстояние циклического сдвига между последовательностями RS.RS1 and RS2 may be of length

. Suitable sequences are CASAC length sequences

or computer-optimized sequences. From one base sequence, additional orthogonal sequences can be derived by cyclically shifting the base sequence, as described in 3GPP TS 36.211, “Physical Channel and Modulation”. For normal CP with

RS per interval, an extension of the time domain block may be used to increase the number of available RS sequences or alternatively to increase the cyclic shift distance between RS sequences.

RS1 and RS2 may be transmitted on the same set of subcarriers. In such embodiments, RS1 and RS2 may be orthogonal. For example, RS1 may be a cyclic shift of the second reference sequence.

In other embodiments, reference sequences may be displayed in a distributed manner, like a data payload, as described above. That is, RSs of different antenna ports are mapped to different comb structures of the frequency domain. For example, for P = 2 antennas: RS for antenna port 0 (for example, RS1) occupies subcarriers with even indices in SC-FDMA symbols with even indices and in subcarriers with odd indices in SC-FDMA symbols with odd indices (or vice versa); and the RS signal for antenna port 1 (e.g., RS2) occupies subcarriers with odd indices in SC-FDMA even-numbered symbols and in subcarriers with even indices in SC-FDMA odd-numbered symbols (or vice versa).

Referring now to FIG. 9, FIG. 9 illustrates an alternative embodiment of a transmission diversity coding apparatus shown in FIG. 7. This alternative embodiment, the device 900, is almost identical with the device 700, with the exception that the device 700 has a single scrambler and a symbol generator, while, in the device 900, a scrambler 704 and a symbol generator (SG) 706 are placed in each branch corresponding to the SC-FDMA symbol.

At device 900, the scrambling code can be made dependent on SC-FDMA characters by initializing each scrambler shown in FIG. 9 at the beginning of each interval with a seed number that depends on the number of the interval or subframe.

и для второго интервала биты

повторяются

и

раз, соответственно. Биты в первом и втором интервале затем скремблируются посредством последовательности

и

элементов в длину, соответственно. Генератор последовательности скремблирования инициализируется в начале каждого интервала с помощью начального числа, которое зависит от номера интервала или подкадра. Скремблированные биты затем отображаются в символы QPSK, и

символов QPSK передаются в каждой SC-FDMA.Other methods are possible to make the scrambling code dependent on SC-FDMA characters. For example, for the first bit interval

and for the second interval bits

are repeated

and

times, respectively. The bits in the first and second interval are then scrambled by means of a sequence

and

items in length, respectively. The scrambling sequence generator is initialized at the beginning of each interval with an initial number, which depends on the number of the interval or subframe. The scrambled bits are then mapped to QPSK characters, and

QPSK characters are transmitted in each SC-FDMA.

повторяется

раз и конкатенируется с блоком битов

, который повторяется

раз, чтобы формировать блок битов

элементов в длину. Эта битовая последовательность затем скремблируется. Генератор последовательности скремблирования инициализируется в начале каждого подкадра с помощью начального числа, которое зависит от номера подкадра. Скремблированные биты затем отображаются в символы QPSK, и

символов QPSK передаются в каждой SC-FDMA.Alternatively, a block of bits

repeated

times and is concatenated with a block of bits

which is repeated

times to form a block of bits

items in length. This bit sequence is then scrambled. The scrambling sequence generator is initialized at the beginning of each subframe with an initial number that depends on the number of the subframe. The scrambled bits are then mapped to QPSK characters, and

QPSK characters are transmitted in each SC-FDMA.

Referring now to FIG. 10, FIG. 10 illustrates a block diagram of an example of a mobile terminal 102 in which a transmission diversity coding apparatus 700 and / or a transmission diversity coding apparatus 900 may be implemented. As shown in FIG. 10, terminal 102 may include: a data processor 1002, which may include one or more microprocessors and / or one or more circuits, such as a specialized integrated circuit (ASIC), user programmable gate arrays (FPGAs) ) etc.; transmitter and receiver 1004 connected to antennas 111 and 112 via antenna port 0 (p0) and antenna port 1 (p1), respectively, for wireless communication; input / output devices 1021 (e.g., display screen 1022); a storage system 1006, which may include one or more non-volatile memory devices and / or one or more volatile memory devices (eg, random access memory (RAM)). In embodiments where the data processor 1002 includes a microprocessor, computer instructions 1008 (i.e., machine-readable code means) may be stored in the storage system 1006. Configuration parameters 1010 may also be stored. Computer instructions 1008 may be executed in a computer program stored using computer-readable means, such as, but not limited to, magnetic media (eg, hard disk), optical media (eg, DVD), memory devices ( e.g. random access memory), etc. In some embodiments, computer instructions 1008 are configured such that when computer instructions 1008 are executed, computer instructions 1008 cause the mobile terminal 102 to perform the steps described above (for example, the steps described above with reference to the flowcharts shown in FIG. 2 and 6). In other embodiments, the mobile terminal 102 is configured to perform the steps described above without the need for computer instructions 1008. That is, for example, the data processor 1002 may simply consist of one or more ASICs. Therefore, the features of the present invention described above can be implemented in hardware and / or software. For example, in specific embodiments, the functional components of the device 700 and / or device 900 described above may be implemented in the terminal 102 by a processor 1002 executing computer instructions 1008, by a processor 1002 operating independent of any computer instructions 1008, or by any suitable combination of hardware and / or software.

While various embodiments of the present invention have been described above, it should be understood that they were presented by way of example only and not limitation. Thus, the breadth and scope of the present invention should not be limited by any of the above illustrative embodiments. Moreover, the invention encompasses any combination of the above elements in all possible variations thereof, unless otherwise indicated herein or otherwise explicitly denied by the context.

Additionally, while the treatments described above and illustrated in the drawings are shown as a sequence of steps, this was done for illustrative purposes only. Accordingly, it is contemplated that some steps may be added, some steps may be skipped, the order of steps may be rearranged, and some steps may be performed in parallel.

Claims (20)

1. Transmission diversity method (200) for precoded by Discrete Fourier Transform (DFT) channels used in a mobile terminal (102) having a first antenna (111) and a second antenna (112), the method comprising the steps of:
generate a block of data symbols,
converting said block of data symbols to generate a first block of converted symbols and a second block of converted symbols,
using the first antenna transmit the first block of converted symbols and the first reference sequence, while the transmission step occurs during the interval of the subframe of the radio frame, and
using the second antenna, during the said interval, a second block of converted symbols and a second reference sequence are transmitted,
wherein the first block of converted symbols is transmitted using the first set of subcarriers,
a second block of transformed symbols is transmitted using a second set of subcarriers that is orthogonal to the first set of subcarriers, and
the first reference sequence and the second reference sequence are transmitted using a third set of subcarriers, which comprises said first set of subcarriers and said second set of subcarriers. 2. The method of claim 1, wherein the first reference sequence is orthogonal to the second reference sequence. 3. The method of claim 2, wherein the first reference sequence is a cyclic shift of the second reference sequence. 4. The method according to any one of paragraphs. 1-3, in which the step of converting said data symbol block comprises the steps of:
dividing the data symbol block into at least a first subunit and a second subunit,
applying a discrete Fourier transform (DFT) to the first subblock to generate a first block of transformed symbols, and
apply the discrete Fourier transform (DFT) to the second subblock to generate a second block of transformed symbols. 5. The method according to claim 4, in which the data symbol block consists of twelve data symbols, and the step of converting said block of twelve data symbols comprises the steps of:
dividing a block of twelve characters into a first sub-block of six characters and a second sub-block of six characters,
applying six (802) DFTs to the first six-character subblock to generate a first block of transformed characters, and
apply six (804) DFTs to a second sub-block of six characters to generate a second block of transformed characters. 6. The method according to p. 1, in which
the step of transmitting the first block of the converted symbols contains steps in which each symbol within the first block of the converted symbols is mapped to a particular subcarrier within the first set of subcarriers and the inverse fast Fourier transform (IFFT) is applied to the first block of the converted symbols, and
the step of transmitting the second block of converted symbols contains the steps of mapping each symbol within the second block of converted symbols to a particular subcarrier within the second set of subcarriers and applying IFFT to the second block of converted symbols. 7. The method according to claim 1, further comprising stages in which:
generating a second block of data symbols,
converting said second block of data symbols to generate a third block of converted symbols and a fourth block of converted symbols,
using the first antenna transmit the third block of converted symbols and the first reference sequence, while the transmission step occurs during the second interval of the subframe, and
using the second antenna, during the second interval, the fourth block of converted symbols and the second reference sequence are transmitted,
wherein the third block of converted symbols is transmitted using the fourth set of subcarriers and
a fourth block of transformed symbols is transmitted using the fifth set of subcarriers, which is orthogonal with the fourth set of subcarriers. 8. The method according to p. 1, in which
the first and fifth subcarrier sets consist only of subcarriers with even indices, and the second and fourth subcarrier sets consist of only subcarriers with odd indices, or
the first and fifth subcarrier sets consist only of subcarriers with odd indices, and the second and fourth subcarrier sets consist of only subcarriers with even indices. 9. Device (102) transmit diversity for pre-encoded by discrete Fourier transform (DFT) channels, the device contains:
the first antenna (111),
a second antenna (112) and
a data processor (1002) connected to the first antenna and the second antenna, wherein the data processor is configured to: (a) generate a data symbol block from the set of message bits; (b) converting said data symbol block to generate a first converted symbol block and a second converted symbol block; (c) use the first antenna to transmit the first block of transformed symbols and the first reference sequence during the interval of the subframe of the radio frame; and (d) use a second antenna to transmit, during said interval, a second block of transformed symbols and a second reference sequence,
wherein the data processor is further configured so that (a) the first block of converted symbols is transmitted using the first set of subcarriers, (b) the second block of converted symbols is transmitted using the second set of subcarriers that is orthogonal to the first set of subcarriers, and (c) the first the reference sequence and the second reference sequence are transmitted using a third set of subcarriers, which comprises said first set of subcarriers and said second set of subcarriers. 10. The device according to claim 9, in which the first reference sequence is orthogonal to the second reference sequence. 11. The device according to p. 10, in which the first reference sequence is a cyclic shift of the second reference sequence. 12. The device according to any one of paragraphs. 9-11, in which the data processor is further configured to convert said block of data symbols by:
dividing the data symbol block into at least a first subunit and a second subunit,
applying a discrete Fourier transform (DFT) to the first subblock to generate a first block of transformed symbols, and
applying a discrete Fourier transform (DFT) to the second subblock to generate a second block of transformed symbols. 13. The device according to p. 12, in which the data symbol block consists of twelve data symbols, and the data processor is further configured to convert said data symbol block by:
dividing a block of twelve characters into a first sub-block of six characters and a second sub-block of six characters,
applying a six (802) DFT to the first sub-block of six characters to generate a first block of transformed characters, and
applying a six (804) size DFT to a second sub-block of six characters to generate a second block of transformed characters. 14. The device according to claim 9, in which the data processor is further configured so that it:
maps each symbol within the first block of converted symbols to a particular subcarrier within the first set of subcarriers and applies the inverse fast Fourier transform (IFFT) to the first block of converted symbols, and
maps each symbol within the second block of converted symbols to a particular subcarrier within the second set of subcarriers and applies IFFT to the second block of converted symbols. 15. The device according to claim 9, in which the data processor is further configured so that:
generate a second block of data characters,
converting said second block of data symbols to generate a third block of converted symbols and a fourth block of converted symbols,
use the first antenna to transmit the third block of transformed symbols and the first reference sequence during the second subframe interval, and
use the second antenna to transmit the fourth block of converted symbols and the second reference sequence during the second interval,
wherein the data processor is further configured such that (a) the third block of converted symbols is transmitted using the fourth set of subcarriers, (b) the fourth block of converted symbols is transmitted using the fifth set of subcarriers, and (c) the fourth set of subcarriers is orthogonal with the fifth set of subcarriers . 16. The device according to p. 15, in which
the first and fifth subcarrier sets consist only of subcarriers with even indices, and the second and fourth subcarrier sets consist of only subcarriers with odd indices, or
the first and fifth subcarrier sets consist only of subcarriers with odd indices, and the second and fourth subcarrier sets consist of only subcarriers with even indices. 17. The device according to claim 9, in which the set of message bits contains one or more HARQ feedback bits. 18. The apparatus of claim 17, wherein the set of message bits further comprises a scheduling request bit. 19. The apparatus of claim 17, wherein the HARQ feedback bits comprise bits obtained by AND logic of several individual HARQ feedback bits. 20. A mobile terminal (102) comprising a transmit diversity device for channels pre-encoded by a discrete Fourier transform (DFT), the device comprising:
the first antenna (111),
a second antenna (112) and
a data processor (1002) connected to the first antenna and the second antenna, wherein the data processor is configured to: (a) generate a block of data symbols from a bit sequence, (c) convert said block of data symbols to generate a first block of converted symbols and a second a transformed symbol block, (d) use a first antenna to transmit a first transformed symbol block and a first reference sequence during an interval of a subframe of a radio frame, and (e) use a second antenna have to transmit during the interval of said second block of transformed symbols and a second reference sequence,
wherein the data processor is further configured so that (a) the first block of converted symbols is transmitted using the first set of subcarriers, (b) the second block of converted symbols is transmitted using the second set of subcarriers that is orthogonal to the first set of subcarriers, and (c) the first the reference sequence and the second reference sequence are transmitted using a third set of subcarriers, which comprises said first set of subcarriers and said second set of subcarriers.

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