HK1170620B - Transmission of information in a wireless communication system - Google Patents

Abstract

Methods, devices, and systems for the transmission of information in a wireless communication system are disclosed. In one embodiment, a method for the transmission of information in a wireless communication system comprises receiving a downlink message (707), wherein the downlink message (707) includes a first control channel element (708); determining a first index (710a) using the location of the first control channel element (708); determining a second index (710b); determining a first orthogonal resource (705a) using the first index (710a); determining a second orthogonal resource (705b) using the second index (710b); spreading an uplink message using the first orthogonal resource (705a) to form a first spread signal; spreading the uplink message using a second orthogonal resource (705b) to form a second spread signal; transmitting the first spread signal using a first antenna(704a); and transmitting the second spread signal using a second antenna (704b).

Description

Information transmission in a wireless communication system

Cross Reference to Related Applications

The present application claims priority from us provisional patent application No.61/235,997 entitled "TRANSMISSION INFORMATION IN A WIRELESS communication system" filed on 21/8/2009. The entire contents of the aforementioned application are incorporated herein.

Technical Field

The present invention relates to wireless communication systems, and more particularly, to information transmission in wireless communication systems.

Background

Wireless communication systems are widely deployed to provide a wide range of voice and data related services, for example. Typical wireless communication systems include multiple-access communication networks that allow users to share common network resources. Examples of such networks are time division multiple access ("TDMA") systems, code division multiple access ("CDMA") systems, single carrier frequency division multiple access ("SC-FDMA") systems, orthogonal frequency division multiple access ("OFDMA") systems, and other similar systems. OFDMA systems are supported by various technology standards, such as evolved Universal terrestrial radio Access ("E-UTRA"), Wi-Fi, worldwide interoperability for microwave Access ("WiMAX"), ultra-Mobile broadband ("UMB"), and other similar systems. In addition, specifications developed by various industry standards organizations, such as the third generation partnership project ("3 GPP") and 3GPP2, describe the implementation of these systems.

As wireless communication systems evolve, more advanced network devices are introduced that provide enhanced features, functionality, and performance. Representatives of such advanced network devices may also be referred to as long term evolution ("LTE") devices or long term evolution-advanced ("LTE-a") devices. LTE is the next step in the evolution of high speed packet access ("HSPA") with higher average and peak data throughput rates, lower latency and better user experience, especially in high demand geographical areas. LTE achieves this higher performance by using wider spectral bandwidth, OFDMA and SC-FDMA air interfaces, and advanced antenna methods.

Communication between a wireless device and a base station may be implemented using a single-in single-out system ("SISO"), a single-in multiple-out system ("SIMO"), a multiple-in multiple-out system ("MIMO"), where both the receiver and the transmitter use only one antenna; in SIMO systems, multiple antennas are used at the receiver and only one antenna is used at the transmitter; in a MIMO system, multiple antennas are used at the receiver and transmitter. SIMO systems may provide increased coverage compared to SISO systems, while MIMO systems may provide improved spectral efficiency and higher data throughput if multiple transmit antennas, multiple receive antennas, or both are used. Further, uplink ("UL") communication refers to communication from a wireless device to a base station. Downlink ("DL") communication refers to communication from a base station to a wireless device.

At 3rd Generation Partnership Project; technical Specification group Address Access Network; physical Channels and Modulation (Release 8), 3GPP TS 36.211 ("LTE Release 8"), support the use of a single antenna for UL transmission support with SC-FDMA. At 3rd Generation Partnership Project; technical Specification Group Radio Access Network; further Advancions For E-UTRA; in Physical Layer accessories (Release 9), 3GPP TR 36.814V9.0.0(2010-03) ("LTE-area 10"), multiple antennas may be used to improve UL performance, for example, by using transmit diversity and spatial multiplexing. Various transmit diversity may be used, such as space frequency block coding ("SFBC"), space time block coding ("STBC"), frequency switched transmit diversity ("FSTD"), time switched transmit diversity ("TSTD"), precoding vector switching ("PVS"), cyclic delay diversity ("CDD"), space code transmit diversity ("SCTD"), orthogonal resource transmission ("ORT"), and other similar schemes.

Disclosure of Invention

Drawings

For those of ordinary skill in the art to understand the disclosure and to put it into practice, reference is now made to the exemplary embodiments illustrated by reference to the drawings. Throughout the drawings, like reference numbers indicate identical or functionally similar elements. In accordance with the present disclosure, the accompanying drawings, which are incorporated in and form a part of the specification, further illustrate exemplary embodiments and explain various principles and advantages, and together with the detailed description, wherein:

fig. 1 shows an example of a wireless communication system.

Fig. 2 is a block diagram of one embodiment of a wireless communication system that employs a control channel structure in accordance with aspects set forth herein.

Fig. 3 illustrates an exemplary uplink channel structure that may be used in a wireless communication system.

Fig. 4 is a block diagram of an example system that facilitates information transfer.

Fig. 5 is a block diagram of an example system that facilitates information transfer using transmit diversity.

Fig. 6 is a block diagram of another example system that facilitates information transfer.

Fig. 7 is a block diagram of one embodiment of a wireless transmission system that employs a transmit diversity scheme in accordance with various aspects described herein.

Fig. 8 illustrates various embodiments of an orthogonal resource mapping method for performing transmit diversity in a wireless communication system in accordance with various aspects described herein.

Fig. 9 illustrates another embodiment of an orthogonal resource mapping method for performing transmit diversity in a wireless communication system in accordance with various aspects described herein.

Fig. 10 illustrates another embodiment of an orthogonal resource mapping method for performing transmit diversity in a wireless communication system in accordance with various aspects described herein.

Fig. 11 illustrates another embodiment of an orthogonal resource mapping method for performing transmit diversity in a wireless communication system in accordance with various aspects described herein.

Fig. 12 illustrates one embodiment of a method of orthogonal resource mapping to perform transmit diversity using reserved control channel elements ("CCEs") in a wireless communication system in accordance with various aspects described herein.

Fig. 13 illustrates another embodiment of an orthogonal resource mapping method for performing transmit diversity in a wireless communication system in accordance with various aspects described herein.

Fig. 14 illustrates another embodiment of a method for orthogonal and quasi-orthogonal resource mapping for performing transmit diversity in a wireless communication system in accordance with various aspects described herein.

Fig. 15 illustrates one embodiment of a method for configuring a wireless device for transmit diversity in a wireless communication system in accordance with various aspects described herein.

Fig. 16 illustrates another embodiment of an orthogonal resource mapping method for performing transmit diversity in a wireless communication system in accordance with various aspects described herein.

Fig. 17 illustrates another embodiment of an orthogonal resource mapping method for performing transmit diversity in a wireless communication system in accordance with various aspects described herein.

Skilled artisans appreciate that elements in the figures are illustrated for clarity, simplicity, and further understanding of the exemplary embodiments and have not necessarily been drawn to scale.

Detailed Description

Although the following discloses example methods, devices, and systems for use in a wireless communication system, those skilled in the art will appreciate that the teachings of the present disclosure are not limited in any way by the illustrated embodiments. Rather, it should be appreciated that the teachings of the present disclosure may be implemented in alternative configurations and environments. For example, although the exemplary methods, devices and systems described herein are described in connection with the configuration of an E-UTRA system, which is the air interface of the 3GPP organization for the LTE upgrade path of a mobile network, one of ordinary skill in the art will readily recognize that these exemplary methods, devices and systems may be used in, and may be configured to correspond with, other systems, as desired. Accordingly, while the following describes the use of example methods, apparatus and systems, persons of ordinary skill in the art will appreciate that the example embodiments disclosed are not the only way to implement such methods, apparatus and systems, and the figures and descriptions should be regarded as illustrative in nature and not as restrictive.

The various techniques described herein may be used for various wireless communication systems. Various aspects described herein are presented as a system that may include a number of components, devices, units, members, modules, peripherals, and the like. Further, these systems may or may not include additional components, devices, units, members, modules, peripherals, and the like. In addition, various aspects described herein may be implemented in hardware, firmware, software, or any combination thereof. It is important to note that the terms "network" and "system" may be used interchangeably. Relational terms such as "above" and "below," "left" and "right," "first" and "second," and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The term "or" is intended to mean an inclusive "or" rather than an exclusive "or". Furthermore, the terms "a" and "an" mean more than one unless explicitly indicated otherwise or otherwise derived from the context in the singular.

A wireless communication system includes a plurality of wireless devices and a plurality of base stations. A base station may also be referred to as a node B ("NodeB"), a base transceiver station ("BTS"), an access point ("AP"), or some other equivalent terminology. Base stations typically include at least one radio frequency ("RF") transmitter and receiver to communicate with wireless devices. In addition, base stations are typically fixed or immobile. For LTE and LTE-A equipment, the base station is also referred to as an E-UTRAN node B ("eNB").

A wireless device used in a wireless communication system may also be referred to as a mobile station ("MS"), a terminal, a cellular phone, a cellular handset, a personal digital assistant ("PDA"), a smart phone, a handheld computer, a desktop computer, a laptop computer, a tablet computer, a set-top box, a television, a wireless device, or some other equivalent terminology. A wireless device may include more than one RF transmitter and receiver, and more than one antenna, to communicate with a base station. Further, wireless devices may be fixed or mobile and may have the ability to move around in a wireless communication system. For LTE and LTE-a devices, the wireless device is also referred to as user equipment ("UE").

Fig. 1 is a block diagram of a system 100 for wireless communication. In fig. 1, system 100 may include more than one wireless device 101, wireless device 101 communicatively linked with more than one base station 102. The wireless device 101 may include a processor 103 coupled to a memory 104, an input/output device 105, a transceiver 106, or any combination thereof, which the wireless device 101 may use to implement various aspects described herein. The transceiver 106 of the wireless device 101 may include more than one transmitter 107 and more than one receiver 108. Further, in association with the wireless device 101, more than one transmitter 107 and more than one receiver 108 may be connected to more than one antenna 109.

Similarly, the base station 102 can include a processor 121, the processor 121 coupled to a memory 122 and a transceiver 123, which can be used by the wireless device 102 to implement various aspects described herein. The transceiver 123 of the base station 102 may include more than one transmitter 124 and more than one receiver 125. Further, in association with base station 102, more than one transmitter 124 and more than one receiver 125 may be connected to more than one antenna 128.

Base station 102 may communicate with wireless device 101 on the UL using more than one antenna 109 and 128 associated with wireless device 101 and base station 102, respectively, and base station 102 may communicate with wireless device 101 on the DL using more than one antenna 109 and 128. Base station 102 may initiate DL information using more than one transmitter 124 and more than one antenna 128, where the information may be received by more than one receiver 108 at wireless device 101 using more than one antenna 109. Such information may relate to more than one communication link between base station 102 and wireless device 101. Once the wireless device 101 receives the information on the DL, the wireless device 101 may process the received information to generate a response related to the received information. The response may be transmitted back on the UL from wireless device 101 using more than one transmitter 107 and more than one antenna 109 and received at base station 102 using more than one antenna 128 and more than one receiver 125.

According to one aspect, wireless communication of control information may be performed using a wireless communication system, such as system 200 shown in fig. 2. In one embodiment, system 200 illustrates a control signaling structure that may be used in a system using LTE or LTE-a devices or other suitable wireless communication technologies. System 200 may include a wireless device 201 communicatively linked with a base station 202. The wireless device 201 may include a processor 203, the processor 203 being coupled to a memory 204, an input/output device 205, a transceiver 206, and a control information processor 209. The transceiver 206 of the wireless device 201 may include more than one transmitter 207 and more than one receiver 208. Both the transmitter 207 and the receiver 208 of the wireless device 201 can be coupled to an antenna 212. Base station 202 may include a processor 221, processor 221 coupled to a memory 222 and a transceiver 223 and a control information processor 226. The transceiver 223 of the base station 202 may include more than one receiver 224 and more than one transmitter 225. Both the transmitter 225 and the receiver 224 of the base station 202 can be coupled to an antenna 228.

As shown in fig. 2, UL control signaling may be carried on, for example, a physical uplink control channel ("PUCCH") 230 or a physical uplink shared channel ("PUSCH") 231. UL data may be carried on, for example, PUSCH 231. DL control signals may be carried on, for example, a physical downlink control channel ("PDCCH") 232, and DL data may be carried on, for example, a physical downlink shared channel ("PDSCH") 233.

In one implementation, the control information processor 226 of the base station 202 can generate or obtain data, control information, or other information for the wireless device 201. The control information can then be initiated on PDCCH 232 and data transmitted on PDSCH using transmitter 225 and antenna 228 of base station 202, where antenna 212 and receiver 208 at wireless device 201 can receive the control information and data. Once the wireless device 201 receives the information on the DL, the control information processor 209 of the wireless device 201 may process the received information to generate a response related to the received information.

The response may then be sent back to the base station 202 on PUCCH 230 or PUSCH 231 (when, for example, PUSCH resources are allocated). The response may be transmitted using the transmitter 207 and antenna 212 of the wireless device 201 and received at the base station 202 using the receiver 224 and antenna 228. Once the base station 202 receives the information on the UL, the control information processor 226 of the base station 202 can process the received information to generate a response related to the received information and facilitate transmission of any generated control information on the DL to the wireless device 201.

In another embodiment, the control information processor 209 of the wireless device 201 may generate: UL control information including an acknowledgement ("ACK") for correctly received data, a negative acknowledgement ("NAK") for incorrectly received data, or both; channel quality information ("CQI"), such as a channel quality indication ("CQI"), precoding matrix index ("PMI"), or rank indicator ("RI"); or any other information. The ACK/NAK may be transmitted using PUCCH format 1a/1b and the CQI may be transmitted using PUCCH format 2/2a/2 b. The wireless device 201 may use PUCCH format 1 for scheduling requests. The PUCCH formats 1/1a/1b may share the same structure as the permanent and dynamic ACK/NAK. The PUCCH format 2/2a/2b may be used for concurrent transmission of CQI and ACK/NAK.

The transmission of control information in a wireless communication system may use an exemplary structure 300 as shown in fig. 3. In fig. 3, structure 300 illustrates a UL control channel structure that may be used in a system using LTE or LTE-a devices or other suitable wireless communication technologies. In structure 300, one frame 301 may include 20 slots 303, each slot 303 having a duration of 0.5 megaseconds (msec), and one subframe 302 may include two slots 303. Each slot 303 may carry 6 or 7 SC-FDMA symbols in the time domain (depending on the type of cyclic prefix used) and may include 12 subcarriers in the frequency domain of each resource block ("RB"). In this example, a conventional cyclic prefix is used, so 7 SC-FDMA symbols can be transmitted in each RB. It is to be appreciated that the claimed subject matter is not limited to this particular channel structure.

Referring to FIG. 3, an example of several RBs 305 is shown. It will be understood by those of ordinary skill in the art that the RB 305 is a time-frequency allocation assigned to a wireless device and may be defined as the smallest unit of resource allocation made by a base station. In addition, the RB 305 may extend over multiple slots 303. The lte ul may allow a very high degree of flexibility, allowing any number of RB 305 ranges, e.g., from a minimum of 6 RBs 305 to a maximum of 100 RBs 305. An RB 305 may be composed of multiple resource elements ("REs") 304, which may represent a single subcarrier over frequency for a time period of one symbol.

Fig. 4 is a block diagram of an example system 400 that facilitates transmission of control information in a wireless communication system. In system 400, a message may be input to a modulator 401. The modulator 401 may apply, for example, quadrature phase shift keying ("QPSK") modulation, binary phase shift keying ("BPSK") modulation, or any other form of modulation. The modulated symbols are then input to spreading logic 402. An index is also input to the spreading logic 402, the index being used to select an orthogonal resource 405, the orthogonal resource 405 including a first spreading sequence 406a and a second spreading sequence 406 b. Spreading logic 402 applies a first spreading sequence 406a and a second spreading sequence 406b to the modulated symbols. Such two one-dimensional ("1-D") spreading sequences may also be calculated or generated and stored in temporary or permanent memory as two-dimensional ("2-D") spreading sequences, each corresponding to an index. The 2-D spreading sequence may be applied to the modulated symbols to perform a spreading operation. In one example, one of the spreading sequences may be a Zadoff-Chu sequence, and the other spreading sequence may be a sequence orthogonal thereto. The modulated symbols are input to a transmitter 403 after spreading for transmission to, for example, a base station using an antenna 404.

When a transmit diversity system uses multiple antennas, spatial orthogonal transmit diversity ("SORTD"), which May also be referred to as space code transmit diversity ("SCTD"), May be applied to the modulated symbols to achieve improved communication performance while maintaining a low peak-to-average power ratio ("PAPR"), a general principle of which is described in 3GPP document R1-091925, Evaluation of transmission diversity for PUCCH in LTE-a, Nortel, 3GPP TSG-RAN WG1#57, San Francisco, US, May 4-8, 2009. Those of ordinary skill in the art will appreciate the necessity to keep the PAPR of the SC-FDMA transmission low. Wireless transmission of information may be performed using a transmit diversity mechanism, such as the exemplary system 500 shown in fig. 5. In fig. 5, a system 500 depicts a SORTD scheme that may be used in a wireless communication system.

Referring to fig. 5, a message is input to a modulator 501. The modulator 501 may apply, for example, quadrature phase shift keying ("QPSK") modulation, binary phase shift keying ("BPSK") modulation, or any other form of modulation. The modulated symbols may then be input to spreading logic 502a and 502 b. Each modulated symbol is spread in both spreading logic 502a and 502 b. The first index and the second index may be input to the spreading logic 502a and 502b, respectively, for selecting the orthogonal resources 505a and 505 b. The first orthogonal resource 505a includes a first spreading sequence 506a and a second spreading sequence 506b, or a pre-computed or concurrently generated combined spreading sequence that includes the first spreading sequence 506a combined with the second spreading sequence 506 b. The second orthogonal resource 505b includes a third spreading sequence 506c and a fourth spreading sequence 506d, or a pre-computed or concurrently generated combined spreading sequence that includes the third spreading sequence 506c combined with the fourth spreading sequence 506 d.

In fig. 5, the spreading logic 502a may apply a first spreading sequence 506a and a second spreading sequence 506b to the modulated symbols, or may apply a pre-computed or concurrently generated combined spreading sequence comprising the first spreading sequence 506a combined with the second spreading sequence 506 b. In parallel, the spreading logic 502b may apply the third spreading sequence 506c and the fourth spreading sequence 506d to the modulated symbols, or may apply a pre-computed or concurrently generated combined spreading sequence comprising the third spreading sequence 506c combined with the fourth spreading sequence 506 d. The modulated symbols are input to transmitters 503a and 503b, respectively, after spreading, and transmitted via antennas 504a and 504 b. The signals transmitted from antennas 504a and 504b may overlap each other in the air. The base station may receive the transmitted message using an antenna and a receiver. Because the base station knows a priori the orthogonal resources 505a and 505b applied to the modulated messages transmitted from each antenna 504a and 504b, the base station can separate each modulated message using the same orthogonal resources 505a and 505 b.

The PDCCH may be transmitted on an aggregation of more than one CCE. When a CCE is used as a control channel element, the CCE is the smallest element used to carry downlink messages (such as PDCCH). The PDCCH may be assigned to use more than one CCE in order to provide the PDCCH with a coding rate corresponding to the quality of wireless communication between the base station and the wireless device. The format of the PDCCH may be determined according to, for example, the size of the payload of the control information, the coding rate, and the number of assigned CCEs. Multiple PDCCHs may be transmitted in a designated control region of a single subframe, which typically occupies the first one or several OFDM symbols. A wireless device may monitor the control region of each subframe and may be able to attempt to discover its corresponding PDCCH, e.g., by blind decoding CCEs in a designated or predetermined search space. In LTE release 8, the index used to extend the orthogonal resources of the uplink ACK/NAK message is derived from the first CCE in the PDCCH in which the corresponding PDSCH is scheduled. Such an index may be derived, for example, using the location of the corresponding CCE.

Wireless transmission of information may be performed using a transmit diversity mechanism, such as the exemplary system 600 shown in fig. 6. In fig. 6, a system 600 depicts a SORTD scheme that may be used in a wireless communication system using LTE or LTE-a devices or other suitable wireless communication technologies.

Referring to fig. 6, a wireless device may transmit a message on the UL, such as an ACK/NAK on a PUCCH format 1a/1b message. It should be appreciated that different UL physical channels (such as PUCCH with format 1/1a/1b, PUCCH with format 2/2a/2b, and PUSCH) use different modulation techniques, which may require different transmit diversity mechanisms to be used per UL physical channel transmission to achieve improved performance. In fig. 6, a message such as ACK/NAK may be input to the modem 601. The modulator 601 may apply, for example, quadrature phase shift keying ("QPSK") modulation, binary phase shift keying ("BPSK") modulation, or any other form of modulation. The modulated symbols may be input to spreading logic 602. An index 609 for selecting the orthogonal resource 605 used to spread the message may be derived using an index of the first CCE 608 of the PDCCH 607 in which the corresponding PDSCH is scheduled. An index 609 may be input to the spreading logic 602, and the index 609 may be used to select an orthogonal resource 605, the orthogonal resource 605 including a first spreading sequence 606a and a second spreading sequence 606 b. Spreading logic 602 applies a first spreading sequence 606a and a second spreading sequence 606b to the modulated symbols. The modulated symbols may be input to a transmitter 603 after spreading. The transmitter 603 may place the spread modulation symbols into RBs for transmission to a base station using the antenna 604. In one example, PUCCH format 1 for a scheduling request may be input to spreading logic 602 with bypass modulator 601 and to transmitter 603 for UL transmission using antenna 604.

LTE-a release 10 may support multiple transmit antennas on the UL. To support transmit diversity, such as SORTD for LTE-a devices, multiple orthogonal resources may be required. According to one aspect, wireless transmission of control information can be performed using a transmit diversity mechanism, such as system 700 shown in fig. 7. In this embodiment, system 700 illustrates a SORTD mechanism that may be used in a system using LTE or LTE-a devices or other suitable wireless communication technologies. SORTD may be applied to, for example, modulated PUCCH format 1/1a/1b messages to achieve improved communication performance while maintaining low PAPR. In system 700, orthogonal resources spread over each transmit antenna are obtained by mapping the indices of those CCEs in the PDCCH to orthogonal resources for PUCCHACK/NAK transmission.

Referring to fig. 7, a message such as a PUCCH format 1/1a/1b message may be input to a modulator 701. The modulator 701 may apply, for example, quadrature phase shift keying ("QPSK") modulation, binary phase shift keying ("BPSK") modulation, or any other form of modulation. The modulated symbols may be input to spreading logic 702a and 702 b. A first index 710a for selecting orthogonal resources 705a used to spread the message may be derived using an index of a first CCE 708 of a PDCCH 707 in which a corresponding PDSCH is scheduled. A second index 710b for selecting the orthogonal resource 705b used to spread the message may be derived by selecting and using the index of the second CCE 709 of the PDCCH 707. The first index 710a and the second index 710b may be input to the spreading logic 702a and 702b, respectively, for selecting the orthogonal resource 705a and the second orthogonal resource 705 b. The first orthogonal resource 705a may include a first spreading sequence 706a and a second spreading sequence 706b, or a pre-computed or concurrently generated first combined sequence including the first spreading sequence 706a and the second spreading sequence 706 b. The second orthogonal resource 705b includes a third spreading sequence 706c and a fourth spreading sequence 706d, or a pre-computed or concurrently generated second combined sequence including the third spreading sequence 706c and the fourth spreading sequence 706 d. Spreading logic 702a may apply first spreading sequence 706a and second spreading sequence 706b to the modulated symbols or may apply a pre-computed or concurrently generated first combined sequence comprising first spreading sequence 706a and second spreading sequence 706 b. In parallel, spreading logic 702b may apply third spreading sequence 706c and fourth spreading sequence 706d to the modulated symbols or may apply a second combined sequence including third spreading sequence 706c and fourth spreading sequence 706d that is pre-computed or generated concurrently. The modulated symbols, after spreading, may be input to transmitters 703a and 703b, respectively, and transmitted via antennas 704a and 704 b.

When there are a plurality of CCEs in the PDCCH and there are more CCEs than the number of required orthogonal resources, an index of each CCE may be used as an index to the orthogonal resource for extending PUCCHACK/NAK. According to one aspect, mapping of orthogonal resources for transmit diversity in a wireless communication system may be performed using various mapping methods, such as methods 800a, 800b, 800c, and 800d illustrated in fig. 8. In these embodiments, methods 800a, 800b, 800c, and 800d illustrate the mapping of the index of selected CCEs to orthogonal resources that may be used in systems using LTE or LTE-a devices or other suitable wireless communication technologies. If the methods 800a, 800b, 800c or 800d, etc. are known in advance by both the wireless device and the base station, such methods may be implemented without requiring other communications between the wireless device and the base station. Alternatively, the wireless device and the base station may exchange communications to select more than one mapping method, such as methods 800a, 800b, 800c, or 800d, among others.

Referring to fig. 8, a method 800a shows multiple CCEs on a PDCCH. The base station may assign PDCCH resources 802a to the wireless device. PDCCH resource 802a may include multiple CCEs. The wireless device may determine the location of first CCE 808a of PDCCH resource 802 a. The location of first CCE 808a may be one of a plurality of CCEs contained in PDCCH resource 802 a. The wireless device may determine the location of first CCE 808a using, for example, blind detection. Second CCE809 a may be selected as the CCE that is logically adjacent and consecutive to first CCE 808 a. First index 810a and second index 811a may be derived from the indices of first CCE 808a and second CCE809 a, respectively, and may be used to select first orthogonal resource 705a of spreading logic 702a and second orthogonal resource 705b of spreading logic 702b for use in orthogonal spreading of messages.

Referring to fig. 8, a method 800b illustrates multiple CCEs on a PDCCH. The base station may assign PDCCH resources 802b to the wireless device. PDCCH resource 802b may include multiple CCEs. The wireless device may determine the location of first CCE 808b of PDCCH resource 802 b. The location of first CCE 808b may be one of a plurality of CCEs contained in PDCCH resource 802 b. Wireless device may determine the location of first CCE 808b using, for example, blind detection. Second CCE809 b may be selected as a fixed CCE span from first CCE 808 a. For example, method 800b shows that second CCE809 b is a fixed span of 2 CCEs away from first CCE 808 a. First index 810b and second index 811b may be derived from the indices of first CCE 808b and second CCE809 b, respectively, and may be used to select first orthogonal resource 705a of spreading logic 702a and second orthogonal resource 705b of spreading logic 702b for use in orthogonal spreading of messages.

Referring to fig. 8, a method 800c illustrates multiple CCEs on a PDCCH. The base station may assign PDCCH resources 802c to the wireless device. PDCCH resource 802c may include multiple CCEs. The wireless device may determine the location of first CCE 808c of PDCCH resource 802 c. The location of first CCE 808c may be one of a plurality of CCEs contained in PDCCH resource 802 c. Wireless device may determine the location of first CCE 808c using, for example, blind detection. Second CCE809c may be selected as the last CCE in PDCCH resource 802c opposite first CCE 808 c. For example, method 800c shows that first CCE 808c is the first CCE of PDCCH resource 802c and second CCE809c is the last CCE of PDCCH resource 802 c. First index 810c and second index 811c may be derived from the indices of first CCE 808c and second CCE809c, respectively, and second orthogonal resource 705b used to select first orthogonal resource 705a of spreading logic 702a and spreading logic 702b for use in the orthogonal spreading of the message.

Referring to fig. 8, a method 800d illustrates multiple CCEs on a PDCCH. The base station may assign PDCCH resources 802d to the wireless device. PDCCH resource 802d may include multiple CCEs. The wireless device may determine the location of first CCE 808d of PDCCH resource 802 d. The location of first CCE 808d may be one of a plurality of CCEs contained in PDCCH resource 802 d. The wireless device may determine the location of first CCE 808d using, for example, blind detection. The selection of the second CCE809d is subject toWhere M is the index of the second or next CCE809d, M is the number of CCEs in PDCCH resource 802d, and N is the number of orthogonal resources needed, and must be satisfied. In one embodiment, the number of orthogonal resources required corresponds to the number of antennas of the wireless device. For m 0, the index is compared to the wholeThe designated CCE or first CCE considered PDCCH in the PDCCH search space corresponds. For example, for M-8 and N-2, the second CCE809d would be selected as M-4, the fourth CCE of PDCCH resource 802d opposite the first CCE 808d of PDCCH resource 802 d. First index 810d and second index 811d may be derived from the indices of first CCE 808d and second CCE809d, respectively, and second orthogonal resource 705b used to select first orthogonal resource 705a of spreading logic 702a and spreading logic 702b for use in the orthogonal spreading of the message.

The following may be desirable: the orthogonal resources within a given RB for a PUCCH are given preference or only the orthogonal resources within the given RB for the PUCCH are used. According to one aspect, mapping of orthogonal resources for transmit diversity in a wireless communication system may be constrained using various mapping procedures, such as the method 900 shown in fig. 9. In this embodiment, the method 900 illustrates limiting the mapping of the index of the selected CCE to orthogonal resources within a particular RB for PUCCH, which may be used in systems using LTE or LTE-a devices or other suitable wireless communication technologies.

Referring to fig. 9, a method 900 illustrates a wrapped around (PUCCH) method, in which an index of a PUCCH resource may be wrapped around using the following equation:

mmod(N_r)，

where index of the m is PUCCH resource, N_rIs the number of orthogonal resources per PUCCH RB. For example, the method 900 shows the first PUCCH orthogonal resource 908 as the last unit of the PUCCH RB 901. If the next unit of PUCCH RB 908 is selected as the second PUCCH orthogonal resource, the second PUCCH orthogonal resource will be associated with a different PUCCH RB. Instead, the PUCCH resource index is surrounded as the start of the PUCCH RB 901, and the second PUCCH orthogonal resource 911 is selected as the first unit of the PUCCH RB 901.

In another embodiment, the selection of the second CCE may be constrained by, and must also satisfy, the following equation:

starting CCE index + (offset)_i)mod(N_x)，

Wherein offset_iIs the CCE offset from the first CCE, and N_xIs the number of CCEs that the CCE derived PUCCH resource will be used to derive the ith PUCCH resource using, for example, method 800a, 800b, 800c or 800d, in the same RB as the RB derived from the first CCE.

Referring to fig. 10, the method 100 shows that 6 CCEs constitute a PDCCH resource 1002. In one example, the first and sixth CCEs may be used to derive two PUCCH resources using two indices. If the PUCCH resource derived from the first three CCEs of PDCCH resource 1002 corresponds to PUCCH RB 1020 and the PUCCH resource derived from the last three CCEs corresponds to another PUCCH RB, the third CCE 1012 may be used to derive a second index 1011. In this way, the method 1000 may allow PUCCH resources from the same PUCCH RB to be used.

Collisions may occur if the enclosed CCEs are used by different wireless devices, resulting in two wireless devices transmitting on the same CCE. In this case, the wireless device may use the next available CCE, e.g., to avoid collisions. Such a case may occur when CCEs of a PDCCH are mapped to PUCCH resources corresponding to different PUCCH RBs. In another embodiment, another alternative is to use CCEs corresponding to PUCCH resources in another PUCCH RB as described in method 1100 shown in fig. 11.

Referring to fig. 11, initially, a first CCE 1108 may be selected in a first PUCCH RB 1120. Instead of selecting the second CCE from the first PUCCH RB1120, the first CCE may be reselected as the first CCE 1109 and may correspond to the second PUCCH RB 1130. The second CCE 1112 may be selected and camped in the same PUCCH RB as the first CCE 1109. The first index 1110 and the second index 1111 may be derived from the indices of the first CCE 1109 and the second CCE 1112, respectively, and may be used to select the first orthogonal resource 705a of the spreading logic 702a and the second orthogonal resource 705b of the spreading logic 702b for use in the orthogonal spreading of the message.

Alternative approaches may be needed when the number of CCEs in the PDCCH is limited to less than the number of orthogonal resources required. In one embodiment, the base station may assign a PDCCH to the wireless device having at least the same number of CCEs as the orthogonal resources needed to support transmit diversity for the wireless device.

In another embodiment, the PDCCH aggregation level may be increased by decreasing the coding rate of the PDCCH to increase the number of CCEs. The index of such additional CCEs may be used to derive additional orthogonal resources for the wireless device.

In another embodiment, the base station may allocate reserved CCEs and grant access to such reserved CCEs. Referring to fig. 12, a method 1200 illustrates multiple CCEs on PDCCH 232. The base station may increase the PDCCH aggregation level to provide additional CCEs 1209 to the wireless device, allowing the wireless device to derive additional orthogonal resources, e.g., to support two antennas for transmit diversity. The first index 1210 and the second index 1211 may be derived from the indices of the first CCE 1208 and the second CCE 1209, respectively, and are used to select the first orthogonal resource 705a of the extension logic 702a and the second orthogonal resource 705b of the extension logic 702b for use in orthogonal extension of the message.

In another embodiment, the wireless device may reduce the number of orthogonal resources and fall back to low order transmit diversity to match the number of CCEs assigned to the wireless device by the base station. Further, the wireless device may use antenna virtualization to map more than one physical antenna to more than one virtual antenna. For example, a wireless device may be able to use four physical antennas for transmit diversity. However, the base station may only have allocated two CCEs in the PDCCH to the wireless device. In this case, the wireless device may map four physical antennas to two virtual antennas. In such an alternative, transmit power compensation may be required due to the use of antenna virtualization. To compensate, the base station may provide transmit power control ("TPC") commands to the wireless device that allow the wireless device to change transmit power by a specified positive or negative amount. In another compensation approach, the base station may transmit a predetermined set of user-specific power adjustments for each PUCCH transmission scheme configured to the wireless device. The wireless device may perform open loop transmit power control on the PUCCH using a predetermined set of user-specific power adjustments associated with the particular PUCCH transmission scheme configured.

In another embodiment, the base station may transmit to the wireless device the location of the unassigned CCE within the PDCCH for the subframe. For CCEs that would otherwise be empty within a PDCCH, the base station may, for example, use downlink control information ("DCI") addressed to a common radio network temporary identifier ("C-RNTI") of another wireless device, or a shared DCI addressed to a common SORTD-RNTI, which implicitly or explicitly provides information about unassigned CCEs within the PDCCH. Alternatively, an additional field within the DL grant DCI may be used by the base station and the wireless device to indicate the PUCCH resource index.

It may be necessary to maintain the same mapping rule as specified in LTE release 8, where the index of the first CCE of PDCCH is mapped to the first orthogonal resource of PUCCH. In one embodiment, an offset from the index of the first CCE in the PDCCH may be used to derive additional orthogonal resources. Such an offset may be fixed or provided by the base station to the wireless device, e.g., dynamically or statically. For example, if a PDCCH is transmitted using the first CCE of the PDCCH, the base station may transmit an offset to the wireless device using such PDCCH. For situations where a collision may occur, the base station may reassign other wireless devices with which a collision may occur to the starting CCE of its next possible PDCCH. For example, the method 1300 shown in fig. 13 shows multiple CCEs on a PDCCH. One wireless device is assigned the first CCE 1308 of a PDCCH that includes only one CCE. Another wireless device is assigned CCE 1309. A potential conflict may occur if the offset used by the wireless device corresponds to the second CCE 1309 being used by another wireless device. To avoid such collisions, the base station can move the CCE of another wireless device from CCE 1309 to CCE 1312. The wireless device can then use the second CCE 1309.

In another embodiment, the base station may broadcast an over-provisioned PUCCH space reserved for permanent ACK/NAK and scheduling request indicator ("SRI"). For LTE release 8, the super-provisioned PUCCH space may not be used. However, the base station and wireless device may know the location of the PUCCH resources reserved for dynamic ACK/NAK. For LTE release 10, the wireless device may use the over-space for permanent ACK/NAK and SRI for sending dynamic ACK/NAK on PUCCH while applying dual transmit or quad transmit diversity systems. The base station may provide the starting boundary of the dynamic ACK/NAK PUCCH resource to LTE-a enabled wireless devices. In another embodiment, a similar mapping may be defined for the mapping of PDCCH CCE indices to PUCCH indices within the dynamic ACK/NAK PUCCH resource space.

In another embodiment, the orthogonal resources may be organized into more than one subset of orthogonal resources. In one example, a wireless device using dual antennas may access a subset of orthogonal resources that includes a first orthogonal resource for a first antenna and a second orthogonal resource for a second antenna. As specified in LTE release 8, the same mapping rule may be used to map a subset of orthogonal resources, and the index and the first CCE of the PDCCH may have a one-to-one mapping. In another embodiment, the organization of the orthogonal resource subsets may be determined using a formula known to both the base station and the wireless device.

It should be appreciated that the above embodiments may be applied to other communication formats, such as PUCCH formats 2/2a/2b and MIMO, coordinated multipoint ("CoMP"), and carrier aggregation ("CA").

In LTE release 8, three orthogonal sequences may be used for coverage in the time direction, and 12 cyclic shift sequences may be used for coverage in the frequency direction. In total, for formats 1a and 1b, a maximum of 36 PUCCH orthogonal resources may be supported in each PUCCH RB. The number of restricted PUCCH orthogonal resources may limit the number of wireless devices multiplexed on the PUCCH RB. According to one aspect, a transmit diversity system can employ quasi-orthogonal resources to increase the number of orthogonal resources available to a system 1400 such as that shown in fig. 14.

In fig. 14, a modulated message may be input to a plurality of spreading logics 1404a, 1404b, and 1404 c. Multiple spreading logics 1404a, 1404b, and 1404c may access orthogonal resource pool 1401 to obtain orthogonal resources and quasi-orthogonal resource pool 1402 to obtain quasi-orthogonal resources. The multiple spreading logics 1404a, 1404b, and 1404c may apply to the modulated message the orthogonal resources of orthogonal resource pool 1401 and the quasi-orthogonal resources of quasi-orthogonal resource pool 1402, or a combination of the orthogonal resources of orthogonal resource pool 1401 and the quasi-orthogonal resources of quasi-orthogonal resource pool 1402 pre-computed or generated concurrently. The modulated message may be transmitted from multiple antennas 1405a, 1405b, and 1405c after spreading. Various schemes known to those of ordinary skill in the art may be used to generate the quasi-orthogonal resources of quasi-orthogonal resource pool 1402

In another embodiment, the orthogonal resources of orthogonal resource pool 1401 may be orthogonal resources as specified by LTE release 8, which may be used as orthogonal resources for transmitting PUCCH from first antenna 1405 a. Quasi-orthogonal resources of quasi-orthogonal resource pool 1402 may then be applied to the modulated message by second spreading logic 1404b and third spreading logic 1404c, respectively, and transmitted from antennas 1405b and 1405.

In another embodiment, the wireless device may use the quasi-orthogonal resources only when the number of CCEs of the PDCCH is less than the number of transmit antennas available to the wireless device.

In another embodiment, the wireless device may exclusively use quasi-orthogonal resources for all its transmit antennas.

In some cases, transmit diversity systems (such as SORTD) may not be optimal, available, or achievable. Therefore, it may be necessary to provide a plurality of transmit diversity schemes according to a specific environment. In one embodiment, for wireless devices with 4 antennas, more than three transmit diversity modes may be used. For example, one mode may be that a SORTD system for two antennas, such as system 700, may be used. The second mode is that a SORTD system for four antennas, such as system 700, may be used. A third mode may use single antenna transmission, such as system 600.

In another embodiment, the base station may statically or dynamically configure the wireless device for any number of transmit diversity modes based on, for example, quality of service ("QoS") of wireless communications between the base station and the wireless device, availability of network resources, or other conditions. The QoS factors may include, for example: word error rate ("WER"), bit error rate ("BER"), block error rate ("BLER"), signal strength, signal-to-noise ratio ("SNR"), signal-to-interference-and-noise ratio ("SINR"), and other factors. For example, a base station can configure a wireless device to transmit using a single antenna, such as system 600, when the wireless device has sufficient QoS. Alternatively, when the QoS of the wireless device is low, such as when the wireless device is at a cell edge, the base station may configure the wireless device to use dual or more antennas in transmit diversity mode.

In order for a base station to statically or dynamically configure the transmit diversity mode of a wireless device, explicit signaling between the base station and the wireless device may be required. According to one aspect, communication of transmit diversity configuration information in a wireless communication system may use a method 1500 as illustrated in fig. 15. In one embodiment, the method 1500 illustrates communication between the base station 1502 and the wireless device 1501 when configuring a transmit diversity mode of the wireless device 1501.

In method 1500, wireless device 1501 may initially transmit using a single antenna for PUCCH. When in the single transmit mode, the wireless device 1501 can send an UL random access channel ("RACH") message to the base station 1502, for example, to request the base station 1502 to configure a transmit diversity mode of the wireless device 1501, represented by 1510. The base station 1502 may acknowledge the RACH 1505 transmitted by the wireless device 1501, which is represented by 1515. The wireless device 1501 can transmit the number of its transmit antennas to the base station 1502, represented by 1520. In response, the base station 1502 can send a higher layer message to configure the transmit diversity mode of the wireless device 1501, which is denoted by 1530. The wireless device 1501 may send an acknowledgement message, represented by 1540. Now, the wireless device 1501 is configured with the transmit diversity mode assigned thereto, and the wireless device 1501 can transmit, for example, a PUDCCH, represented by 1550, using its configured transmit diversity mode.

The methodology 1500 may also be applied to other channel formats, such as PUSCH and PUCCH formats 2/2a/2 b. It should be noted that other channel formats may require other transmission diversity modes. For example, the transmission mode for PUSCH may be a precoding-based SM-mode, an STBC-based mode, a single antenna transmission mode, or any other mode or combination of modes. Further, the transmission mode for PUCCH format 2/2a/2b may use STBC or STBC based mode, single antenna transmission mode, or any other mode or combination of modes.

For additional orthogonal resources used for transmit diversity, such as SORTD, higher layer signaling may be used to convey the assignment of orthogonal resources. In LTE release 8, for PUCCH format 1 and PUCCH format 1a/1b, for semi-persistent scheduling ("SPS") transmissions, orthogonal resources may be assigned using higher layer signaling. In one embodiment, with the orthogonal resource mapping defined by the method 1600, when the DCI format indicates a persistent DL scheduling activation, a higher layer may provide an index to one of four PUCCH resource indices using TPC commands for the PUCCH field. Further, with the orthogonal resource mapping defined by method 1700, TPC commands for the PUCCH field may be mapped to the multidimensional orthogonal resource for the PUCCH. In fig. 16, a method 1600 illustrates mapping of orthogonal resources for PUCCH when a wireless device uses one antenna. In fig. 17, a method 1700 shows mapping of orthogonal resources for PUCCH when the wireless device uses two antennas, e.g., in SORTD mode.

In another embodiment, after deriving PUCCH resources for a first antenna of the wireless device using TPC commands for the PUCCH field, the PUCCH resources for the remaining antennas may be derived using a pre-configured formula or mapping table (such as a fixed or configurable offset).

As discussed previously, there is a need to reduce the number of transmission collisions between wireless devices of a wireless communication system. The likelihood of transmission collisions will depend on the transmit diversity mode used by the wireless device. Because the base station can control the allocation of PUCCH resources among the wireless devices controlled by the base station, the base station can manage the scheduling and allocation of PUCCH resources to reduce the likelihood of transmission collisions. The base station may manage scheduling and allocation of PUCCH resources using multiple metrics. For example, the base station may use metrics associated with the following numbers: a number of PUCCH resource collisions, a number of PUCCH resource collisions for wireless devices using only one PUCCH resource, a number of PUCCH resource collisions for wireless devices using multiple PUCCH resources. Based on these metrics, the base station may configure its system parameters to, for example: for a wireless device using one PUCCH resource, eliminating the possibility of collision; reducing the collision probability to no more than one collision for a wireless mobile device using two PUCCH resources; reducing the collision probability to no more than two collisions for a wireless mobile device using four PUCCH resources; other requirements; or a combination thereof.

In another embodiment, the downlink message may be, for example, a physical downlink control channel message.

In another embodiment, the second control channel element may be adjacent and contiguous to the first control channel element, for example.

In another embodiment, the second control channel element may be, for example, a fixed span from the first control channel element.

In another embodiment, the second control channel element may be, for example, the last control channel element of a downlink message relative to the first control channel element.

In another embodiment, the second control channel element may satisfy, for example:where M is the index of the second control channel element, M is the number of control channel elements in the downlink message, and N is the number of required orthogonal resources.

In another embodiment, the plurality of indices are determined by using a downlink message, e.g., using a plurality of CCEs of the downlink message, wherein each index of the plurality of indices is selected using a location of a neighboring and consecutive CCE.

In another embodiment, the plurality of indices may be determined by using a downlink message, e.g., using a plurality of CCEs in the downlink message, where each index of the plurality of indices is selected using a location of a CCE of a separate fixed span.

In another embodiment, the plurality of indices may be determined by using a downlink message, e.g., using a plurality of CCEs in the downlink message, wherein each index of the plurality of indices uses a value that satisfiesWhere M is an index of each of the plurality of CCEs, M is a number of CCEs in a downlink message, and N is a number of required orthogonal resources.

In another embodiment, a plurality of orthogonal signals may be generated, for example, by determining a plurality of first spreading sequences using a plurality of orthogonal resources; generating a plurality of first spreading sequence signals by applying the plurality of first spreading sequences to an uplink message; determining a plurality of second spreading sequences using the plurality of orthogonal resources; and generating the plurality of orthogonal signals by applying the plurality of second spreading sequences to the plurality of first spreading sequence signals.

In another embodiment, a plurality of orthogonal signals may be generated, for example, by determining a plurality of first spreading sequences using the plurality of orthogonal resources; determining a plurality of second spreading sequences using the plurality of orthogonal resources; generating a plurality of combined spreading sequences by applying the plurality of first spreading sequences to the plurality of second spreading sequences; and generating the plurality of orthogonal signals by applying the plurality of combined spreading sequences to an uplink message.

Having shown and described exemplary embodiments, other adaptations of the methods, devices, and systems described herein may be made by suitable modifications by one of ordinary skill in the art without departing from the scope of the present disclosure. Some of these potential modifications have been mentioned herein, and others will be apparent to those of ordinary skill in the art. For example, the examples, embodiments, etc. discussed above are illustrative and are not necessarily required. The scope of the present disclosure should, therefore, be construed in accordance with the following claims and is understood not to be limited to the details of structure, operation, and function shown and described in the specification and drawings.

As set forth above, the described disclosure includes the aspects set forth below.

Claims (16)

1. A method of operating a user equipment in a wireless communication system, the method comprising:

detecting a downlink control channel, wherein the downlink control channel comprises a first control channel element;

determining a first index using a location of the first control channel element;

determining a second index based on the first index;

determining a first indicator of a first orthogonal resource using the first index;

determining a second orthogonal resource using the second index;

spreading an uplink message based on the first orthogonal resource to form a first spread signal;

spreading the uplink message using the second orthogonal resource to form a second spread signal;

transmitting the first spread signal using a first antenna; and

transmitting the second spread signal using a second antenna.

2. The method of claim 1, wherein the second index is determined using a location of a second control channel element of the downlink control channel.

3. The method of claim 1, wherein the determining a second index further comprises: obtaining the second index from another downlink message.

4. The method of claim 1, wherein the second index is determined using a location of the first control channel element.

5. The method of claim 1, wherein the second index is determined using the first index.

6. A method of operating a user equipment in a wireless communication system, the method comprising:

detecting, by a wireless device, a downlink control channel from a base station;

determining a plurality of indices using the downlink control channel;

determining a plurality of indicators for a plurality of orthogonal resources using the plurality of indices;

generating a plurality of orthogonal signals by applying the plurality of orthogonal resources to an uplink message; and

transmitting the plurality of orthogonal signals from the wireless device to the base station.

7. The method of claim 6, wherein said transmitting the plurality of orthogonal signals from the wireless device to the base station further comprises:

transmitting the plurality of orthogonal signals using a plurality of antennas of the wireless device.

8. The method of claim 6, wherein the determining a plurality of indices using the downlink control channel further comprises:

determining a first index of the plurality of indices using a location of a first control channel element of a plurality of control channel elements, wherein the downlink control channel comprises the plurality of control channel elements; and

determining other indices of the plurality of indices using another downlink message.

9. The method of claim 6, wherein the determining a plurality of indices using the downlink control channel further comprises:

determining a first index of the plurality of indices using a location of a first control channel element of a plurality of control channel elements, wherein the downlink control channel comprises the plurality of control channel elements; and

determining other indices of the plurality of indices using the location of the first control channel element of the plurality of control channel elements.

10. The method of claim 6, wherein the determining a plurality of indices using the downlink control channel further comprises:

determining a first index of the plurality of indices using a location of a first control channel element of a plurality of control channel elements, wherein the downlink control channel comprises the plurality of control channel elements; and

determining other indices of the plurality of indices using the first index of the plurality of indices.

11. An apparatus in a wireless communication system, comprising:

a processor coupled to a memory containing processor-executable instructions;

a receiver and a transmitter coupled to the processor;

wherein the receiver is operative to:

detecting a downlink control channel from a base station;

wherein the processor is operative to:

deriving a first index using a position of a first control channel element of the downlink control channel;

deriving a second index based on the first index;

determining a first indicator of a first orthogonal resource using the first index;

determining a second indicator of a second orthogonal resource using the second index;

generating a first orthogonal signal by applying the first orthogonal resource to an uplink message;

generating a second orthogonal signal by applying the second orthogonal resource to the uplink message; and

wherein the transmitter is operative to:

transmitting the first orthogonal signal and the second orthogonal signal to the base station.

12. The apparatus of claim 11, wherein the processor is further operative to: deriving the second index using a position of a second control channel element of the downlink control channel.

13. The apparatus of claim 11, wherein the processor is further operative to: deriving the second index by obtaining the second index using another downlink message.

14. The apparatus of claim 11, wherein the processor is further operative to: deriving the second index using a location of the first control channel element.

15. The apparatus of claim 11, wherein the processor is further operative to: deriving the second index using the first index.

16. The apparatus of claim 11, wherein the transmitter is further operative to:

transmitting the first quadrature signal using a first antenna; and

transmitting the second orthogonal signal using a second antenna.