WO2011068505A1

WO2011068505A1 - Multiple levels of robustness within a single physical layer pipe

Info

Publication number: WO2011068505A1
Application number: PCT/US2009/066309
Authority: WO
Inventors: Miika Tupala; Jani Vare; Jyrki Alamaunu
Original assignee: Nokia Corporation; Nokia, Inc.
Priority date: 2009-12-02
Filing date: 2009-12-02
Publication date: 2011-06-09

Abstract

Partial data streams are included in the same physical layer pipe over a communications channel in accordance with different modulation schemes and code rates. Consequently, a receiver can extract the first and second partial data streams from the same physical layer pipe of a signal received on the communications channels based on the associated signaling information, where each partial data stream may be associated with a physical layer pipe component. Before transmission, cells from different physical layer pipe components are multiplexed to form a combined data stream. The ordering of cells within the combined data stream may then be permuted so that different mappings of the physical layer pipe components to carriers in many consecutive orthogonal frequency division multiplexing symbols may be insured. Signaling information may included in the transmitted data stream so that a receiver can extract information from the physical layer pipe components in accordance with the related modulation schemes and code rates of each physical layer pipe component.

Description

MULTIPLE LEVELS OF ROBUSTNESS WITfflN A SINGLE PHYSICAL LAYER

PIPE

BACKGROUND

[01] Broadcast or multicast systems support the delivery of data services. For example they are used for the digital video broadcasting (DVB). Broadcast or multicast transmission may consist of frames with a preamble with PI and P2 symbols that are used for Layer 1 (LI) signaling. The majority of the data symbols may be allocated for different physical layer pipes (PLP) that carry service data. As known in the art, a PLP often denotes a physical layer time division multiplex (TDM) channel that is carried by specified sub-slices, where a sub-slice is a group of cells from a single PLP, which before frequency interleaving, is transmitted on active Orthogonal Frequency Division Multiplexing (OFDM) cells with consecutive address over a single radio frequency (RF) channel. Different PLPs may carry data that has been modulated using schemes based on different constellations or other modulation parameters, where data in different PLPs may be coded using different FEC schemes. The broadcast or multicast systems may consist of many service components, including audio and multiple video components. Multiple video components, for example, to provide different quality levels through scalable video coding, may be used when delivering a service to a user. Furthermore, synchronizing the components may be important to enhance the user experience.

[02] The slices and sub slices of the PLPs, auxiliary streams, and dummy cells may be mapped into the symbols of the frame. Each frame may start with a PI symbol followed by one or more P2 symbols. The LI pre- and LI post signaling may first be mapped into P2 symbol(s). Ll-pre signaling may denote signaling carried in the P2 symbols having a fixed size, coding and modulation, including basic information about the system as well as information needed to decode the LI -post signaling, while LI -post signaling may denote signaling carried in the P2 symbol carrying more detailed LI information about the system and the PLPs. PLPs, auxiliary streams, and dummy data cells fill the remaining cells in the frame. PLPs are classified into three types as indicated in LI post signaling field PLP TYPE: common PLP, data PLP (type 1), and data PLP (type 2). Common and type 1 PLPs typically have exactly one sub-slice per T2 frame, whereas type 2 PLPs have between 2 and 6480 sub-slices per T2 frame. The common PLPs may be transmitted at the beginning of the frame. Data PLPs (type 1) may be transmitted directly after the common PLPs. Data PLPs (type 2) may then be transmitted directly after the data PLPs (type 1). The auxiliary stream or streams, if any, follow the type 2 PLPs and may be followed by dummy cells.

[03] Although the different types of PLPs, as described above in accordance with traditional systems, are intended to be used for creating different levels of robustness, the degree of robustness within a PLP is typically non-varying.

BRIEF SUMMARY

[04] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

[05] One or more aspects relate to transmitting a first partial data stream and a second partial data stream on a same physical layer pipe over a communications channel in accordance with different modulation schemes and first code rate. Consequently, a receiver can extract the first and second partial data streams from the same physical layer pipe of a signal received on the communications channels based on the associated signaling information.

[06] According to another aspect, each partial data stream comprises a physical layer pipe component. A first plurality of cells from a first physical layer pipe component and a second plurality of cells from a second physical layer pipe component are multiplexed to form a combined data stream. The ordering of cells within the combined data stream is then permuted so that different mappings of the physical layer pipe components to carriers in an increased number of consecutive orthogonal frequency division multiplexing symbols may be insured. With some embodiments, this characteristic is obtained by selecting the size of a permutation pattern (K) so that the number of data carriers (Cd_ata) in one orthogonal frequency division multiplexing symbol is not divisible by K.

[07] According to another aspect, signaling information is included in the transmitted data stream so that a receiver can extract information from the physical layer pipe components in accordance with the different modulation schemes and code rates of each physical layer pipe component.

[08] According to another aspect, each physical layer pipe component may be mapped to a different service component of a corresponding service. However, physical layer pipe components may be distinct from service components since a physical layer pipe component is characterized by its own robustness level (for example, modulation and/or coding) and may carry one or more service components.

BRIEF DESCRIPTION OF THE DRAWINGS

[09] Certain embodiments are illustrated by way of example and not limited in the accompanying figures in which like reference numerals indicate similar elements and in which:

[10] Figure 1 shows a block diagram for transmitting different components in different physical layer pipes (PLPs).

[11] Figure 2 shows an exemplary functional block diagram for interleaving, multiplexing, and permuting within a PLP with two PLP components by a transmitter portion of a wireless device according to one or more aspects described herein.

[12] Figure 3a shows an exemplary embodiment in which two PLP components are multiplexed in a transmitter according to one or more aspects described herein.

[13] Figure 3b shows an exemplary embodiment in which two PLP components are multiplexed in a transmitter according to one or more aspects described herein.

[14] Figure 4a shows an exemplary permutation block in a transmitter according to one or more aspects described herein.

[15] Figure 4b shows an exemplary permutation block in a transmitter according to one or more aspects described herein.

[16] Figure 5 shows an exemplary functional block diagram of a receiver according to one or more aspects described herein. [17] Figure 6 shows an exemplary permutation block at a receiver according to one or more aspects described herein.

[18] Figure 7 shows an exemplary de-multiplexer at a receiver according to one or more aspects described herein.

[19] Figure 8 shows an exemplary content of LI configurable signaling according to one or more aspects described herein.

[20] Figure 9a shows an exemplary embodiment of PLP component signaling, where one or more PLP components are announced within a loop structure according to one or more aspects described herein.

[21] Figure 9b shows an exemplary embodiment of PLP component signaling, where one or more PLP components are announced within a loop structure according to one or more aspects described herein.

[22] Figure 10a shows an exemplary embodiment of PLP component signaling, where each PLP has high robustness and low robustness components according to one or more aspects described herein.

[23] Figure 10b shows an exemplary embodiment of PLP component signaling, where each PLP has high robustness and low robustness components according to one or more aspects described herein.

[24] Figure 1 1 shows an exemplary apparatus that transmits content over a wireless channel in which a PLP includes a plurality of PLP components according to one or more aspects described herein.

[25] Figure 12 shows an exemplary apparatus that receives content over a wireless channel in which a PLP includes a plurality of PLP components according to one or more aspects described herein.

[26] Figure 13 shows a flow diagram for transmitting content over a wireless channel in which a PLP includes a plurality of PLP components according to one or more aspects described herein. [27] Figure 14 shows a flow diagram for receiving content over a wireless channel in which a PLP includes a plurality of PLP components according to one or more aspects described herein.

DETAILED DESCRIPTION

[28] In the following description of the various embodiments, reference is made to the accompanying drawings, which form a part hereof, and in which are shown by way of illustration various embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural and functional modifications may be made without departing from the scope of the present invention.

[29] A multimedia service may include different components for conveying different portions of a service (for example, audio and video). Content and other services that may be transmitted in a broadcast or multicast network may include many service components. For example, a high definition video may include a standard definition component that provides a base amount of content data and a high definition component that supplements the base content data with high definition information. Although the physical layer pipes (PLPs) are used for creating different robustness levels, traditional systems (for example, in accordance with frame structure channel coding and modulation for a second generation digital terrestrial television broadcasting system (DVB-T2), DVB Document A122rl, January 2008) often encounter deficiencies when transmitting different service components in separate PLPs.

[30] Figure 1 shows an example block diagram depicting the transmission of different components in different physical layer pipes (PLPs) in a DVB T2 frame.

[31] Some existing systems may support different service components within a single PLP, but traditional systems support only one modulation and code rate within each PLP. However, it may be desirable for a service to utilize different components with different degrees of robustness. The more robust base layer component may be received even in bad reception conditions, while the lesser level of robustness (for example, corresponding to greater resolution of service content) may be obtainable in better conditions by receiving the less robust enhancement layer component. In addition, an audio component of a service does not require as high a degree of robustness as it might be required by the video component of that same service.

[32] In at least some embodiments, at least two combinations of modulation and coding are supported within single PLP, and components can be separately decoded. This may be achieved by separated interleaving and/or multiplexing partial data streams (for example, PLP components) into one data stream and/or utilizing a permutation function to improve frequency diversity. Also, a backwards compatible method for signaling the new operations will be discussed.

[33] Figure 2 shows an exemplary functional block diagram 200 for interleaving, multiplexing, and permuting within PLP 261 of two PLP components (partial data streams) 251 and 252 by a transmitter according to one or more aspects described herein. While the exemplary embodiment shows two PLP components, other embodiments may support a different number of PLP components with PLP 261. With some embodiments, the number of PLP components per single PLP may be limited by the signaling format. For example, with a corresponding 4-bit signaling field, a maximum of 16 PLP components per single PLP may be supported.

[34] PLP components 251 and 252 may be distinct from service components since a PLP component may be characterized by its own robustness level (for example, modulation and/or coding) and may carry one or more service components. Exemplary embodiments may support different mappings of service components to PLP components that may be determined at a higher protocol layer rather than at layer 1.

[35] As illustrated in Figure 2, the inputs (for example, PLP components 251 and 252) in functional diagram 200 comprise two streams of complex constellation symbols that have been transformed from binary data with their own modulation and code rate. Consequently, PLP components 251 and 252 may each have a different modulation type and FEC type than the other. PLP components 251 and 252 are separately interleaved by interleavers 201 and 202, respectively, allowing a receiver to access both PLP components 251 and 252 without de-interleaving the whole PLP. However, different PLP components may utilize the same modulation scheme and code rate, different modulation schemes and the same code rate, or the same modulation scheme and different code rates. The data streams may then be multiplexed by multiplexer 203, where the operation is further described in connection with Figures 3a and 3b. Because PLP components 251 and 252 may have a different amount of data, multiplexer 203 stops reading an amount of data (cells) from a branch if all data from the corresponding PLP component has been already read. The amount of cells for each PLP component may be calculated from LI signaling. The ordering of cells in the multiplexed data stream may then be permuted by permutation block 204 (which may comprise an electronic circuit that may be implemented with discrete components or with integrated circuits) before transmitting the data stream in PLP 261. The operations of permutation block 204 are further described in connection with Figures 4a and 4b.

[36] Figure 3a and 3b shows exemplary embodiments of multiplexer 203, in which two PLP components are multiplexed according to one or more aspects described herein. In the exemplary embodiment shown in Figure 3a, multiplexer 301 reads one cell and moves to the next branch. For example, multiplexer 301 selects cell 351a followed by cells 353a, 352a, and 354a as depicted as cells 351b, 353b, 352b, and 354b, respectively in the output stream of multiplex 301. If one of the branches has does not have additional input cells, multiplexer 301 stops reading from that branch.

[37] With some embodiments, parameters Mi, and M₂ may be used if the data rates of the two branches are different. In this case, the multiplexer reads M„ cells from the n^th associated branch before moving to the next branch. In the exemplary embodiment shown in Figure 3b, three cells 361a, 362a, and 363a are first read from the first PLP component, and subsequently one cell 367a is read from the second PLP component as depicted as cells 361b, 362b, 363b, and 367b, respectively, in the output stream of multiplexer 302. Cells 364a, 365a, and 366a are then selected by multiplexer 302 as depicted as 364b, 365b, and 366b, respectively, in the output stream. As will be discussed, parameters M_n may be included in the LI configurable signaling (for example, shown as PLP_SUB_MUX_RATE field 906 in Figure 9a.). In the exemplary embodiment shown in Figure 3a, parameters Mi equal M₂ equal 1, which are default values so that no additional signaling information may be required.

[38] Figure 4a shows an exemplary operations performed by a permutation block 400a in a transmitter according to one or more aspects described herein. Permutation block 400a is one example of operations that may be carried out in block 204 of Figure 2 and formatter 1 102 of Figure 1 1. Cells of the first PLP component and cells of the second PLP component are obtained from multiplexer 301 as previously discussed with Figure 3a. One of the purposes of permutation block 400a is to break the regular structure produced by the multiplexer 300a. This may be performed to insure that the cells of the PLP components are not mapped to the same carrier frequencies. Permutation block 400a may include a serial-to-parallel (S P) converter 401 , mapper 402 that changes the order of the cells, and a parallel-to-serial (P/S) converter 403. With the exemplary embodiment shown in Figure 4a, cells 451, 452, 453, 454, and 455 are mapped into the fifth , first, second, third, and fourth positions, respectively, by mapper 402.

[39] A PLP component pattern period is the number of cells, after which the ordering of the PLP components repeats itself. In general, if there are N PLP component streams multiplexed, for example, the PLP component pattern period of the input is N, and K parallel streams are produced by the S/P block, the period of the PLP component pattern at the output of the permutation may be given by N*K, if N≠K, and K, if N=K. Different mappings of the PLP components to carriers in many consecutive OFDM symbols may be insured by selecting K such that the number of data carriers, C_data, in one OFDM symbol should not be divisible by K.

[40] In reference to a specific example like the DVB-T2 standard, for example, the number of data carriers in one OFDM symbol is equal to 6208 (DVB-T2, 8K fast Fourier transform (FFT), pilot pattern type PP1), K is equal to five, and there are two PLP components multiplexed (N=2), where one OFDM symbol includes 620 full PLP component pattern periods and eight cells. Consequently, the mapping of the next OFDM symbol should not start from the same phase of the PLP component pattern period, which ensures a different carrier mapping after frequency interleaving. Because the remainder is eight, for example, the start position with respect to the PLP component pattern period is shifted by two, and the period is equal to ten, the mapping repeats itself after five OFDM symbols. However, with DVB-T2 transmission the frequency interleaving function is the same only for every other OFDM symbol. Consequently, after frequency interleaving the same carrier, mapping is repeated after ten OFDM symbols. Without permutation the PLP components would be mapped to the same carriers, because N=2 and the number of data carriers is even. The frequency interleaver would have different function for every other OFDM symbol. For this example, performing the permutation may increase the repetition period from two OFDM symbols to ten OFDM symbols.

[41] According to another aspect, the input to the permutation block may be an integer number of baseband (BB) frames. A BB frame may consist of one or more cells, and the number of cells per BB frame depends on the configured modulation. To avoid padding, the serial-to-parallel block may be configured so that the number of input cells may be divisible by . In a DVB-T2 based system, selecting K=5 may satisfy both of the requirements. The number on PLP component streams could be freely selected because all possible values of C_data are indivisible by five.

[42] Figure 4b shows an exemplary operation performed by a permutation block 400b, which provides a generalized approach to permutation block 400a. Permutation block 400a is one example of operations that can be carried out in block 204 of Figure 2 and formatter 1102 of Figure 11. K cells are presented by serial-to-parallel converter 404 to mapper 405 according to one or more aspects described herein. The length of the permutation, K, is equal to the output dimension of serial-to-parallel converter 404. Mapper 405 consequently may permute the ordering of the K cells, and parallel-to- serial converter 406 may generate a serial data stream in accordance with the permuted reordering. The permutation mapping shown with mapper 405 is an exemplary embodiment. However, other embodiments may support other mappings.

[43] One of the purposes of the permutation function that is performed by mapper 405 is to ascertain that the cells of particular PLP component are not transmitted on the same subcarriers in all OFDM symbols, which have the same frequency interleaving. With an aspect of an exemplary embodiment, the permutation function may be configured with a fixed length, which may be selected so that it is compatible for all parameter combinations (FFT size, pilot pattern) of DVB-T2. However, some embodiments may include signaling for specifying the permutation as will be discussed.

[44] Figure 5 shows an exemplary functional block diagram 500 of a receiver according to one or more aspects described herein. As previously discussed. PLP components may be multiplexed at a cell level so that the PLP components can be included in a single PLP 561. Functional block diagram 500 may perform reverse functions in relation to the corresponding transmitter (which is shown as functional diagram 200 in Figure 2).

[45] Functional block diagram 500 first demodulates (not explicitly shown in Figure 5) the OFDM symbols that belong to the desired PLP. Inverse permutation (performed by permutation block 501) and de-multiplexing (performed by de-multiplexer 502) may then commence when the first OFDM symbol is received. Functional block diagram 500 may select only one PLP component from multiple PLP components and delete the unwanted cells immediately after de-multiplexing. For example, the receiver may be interested in only one of the available PLP components. Hence, only one (or more) of the PLP components may be selected. Consequently, less memory may be needed in functional block diagram 500 with single component reception so that unused memory may be used for processing another PLP.

[46] After de-multiplexing by de-multiplexer 502, each de-multiplexed data stream may be de-interleaved separately by de-interleavers 503 and 504 to perform the inverse of the operations performed by interleavers 201 and 202 as shown in Figure 2. In some embodiments the de-interleavers may be realized within one module.

[47] Figure 6 shows an exemplary operation performed by permutation block 501 (as shown in Figure 5 and as further depicted as re-formatter 1202 in Figure 12) that may be utilized in functional block diagram 500 of a receiver according to one or more aspects described herein. Serial-to-parallel converter 601 may convert the received data stream into a parallel format. The cells are then reordered by reverse mapper 602 so that the cells are in the same order as before processing by transmit permutation 204 (shown in Figure 2). Parallel-to-serial converter 603 may convert the parallel format to a serial format (shown as output stream) so that the PLP components may be fed to de-multiplexer 502. While Figure 6 depicts an exemplary embodiment in which K=5, other embodiments may support other values of K, for example, where K>5.

[48] Figure 7 shows an exemplary de-multiplexer 502 that may be utilized in functional block diagram 500 according to one or more aspects described herein. In this example PLP component 552 has fewer cells than PLP component 551, and consequently the terminating portion of multiplexed stream 651 (from permutation block 501 as shown by Figure 6) consists only of cells from the first PLP component. With some embodiments, de-multiplexer 502 incorporates counters for both output branches, whose initial values are set to the number of cells for each PLP component. The value of the counter is decreased after outputting each cell. Once the counter value reaches zero, de-multiplexer 502 no longer assigns cells to that branch.

[49] The exemplary multiplexed data stream 651 consists of re-ordered PLP component cells from permutation block 501. The number of cells for each PLP component 551 and 552 may be different and may be calculated from signaling information by:

_ N_LDPC - PLP _SUB_NUM _ BLOCKS

E - ^L) where NLDPC is the FEC block size (for example in a DVB-T2 system 16200 or 64800) signaled by PLP FEC TYPE field 801 (as shown in Figure 8 where the FEC type is the same for every PLP component). NBITS_PER_CELL is the number of bits per cell and specifies the PLP component modulation, which is signaled by PLP_SUBJVIOD field 902 as shown in Figure 9a.

[50] Figure 8 shows an exemplary content 800 of a LI configurable signaling format according to one or more aspects described herein. The content 800 may be consistent with DVB-T2 standards. With some embodiments, content 800 includes general parameters that are common for all PLPs as well as PLP-specific parameters (associated with a PLP designated by PLP ID field 803) that are signaled in the PLP loop.

[51] With some embodiments, signaling both interleaving and multiplexing parameters may be performed in a backwards compatible way in relation to traditional systems by defining a new PLP TYPE field 805, for which the new signaling may be performed in parallel to the PLP-specific signaling typically performed by traditional systems. With other embodiments, the additional signaling parameters may be included in a LI extension signaling block. In addition to configurable signaling, content 800 may also include LI dynamic and extension fields.

[52] In accordance with some embodiments, Table 1 shows the signaling bits for the PLP TYPE field 805, which may have three specified entries. The remaining entries may be reserved for future use. With one aspect, an additional PLP type is specified with respect to traditional systems and is designated as Data PLP Type 3.

Table 1: Example of signalling format for the PLP TYPE field

[53] Exemplary embodiments for the signaling structures for the PLP component signaling are shown in Figures 9a, 9b, 10a, and 10b, which may be sent in conjunction with content 800 as shown in Figure 8. With some exemplary embodiments, as shown in Figure 9a, the signaling structure may incorporate a loop structure for the PLP components, including modulation, code rate, the number of FEC blocks per interleaving frame, and indexing for each PLP component. For other embodiments, as shown in Figure 10a, the signaling structure may incorporate a simplified structure, in which only two PLP components may be carried within each PLP, which is designated as high robustness and low robustness PLP components. Multiplexing may be performed in accordance with multiplexer 301 (as shown in Figure 3a) and consequently PLP SUB MUX RATE field 906 is not specified as with the embodiment shown in Figure 9a.

[54] With some exemplary embodiments, signaling may be transmitted within the DVB configurable signaling. In other embodiments, some of the signaling fields may be transmitted in DVB dynamic signaling, for example, to support variable bit rates for the PLP components. The LI post-signaling may contain parameters which provide sufficient information for the receiver to decode the desired physical layer pipes. The LI post-signaling may further consist of two types of parameters, which are, configurable and dynamic. The configurable parameters may remain the same for the duration of one superframe (one superframe carries always more than one T2 frame), whilst the dynamic parameters provide information which may be specific for the current frame. The values of the dynamic parameters may change during the duration of one superframe, while the size of each field should remain the same. [55] Referring to Figure 9a, some exemplary embodiments support PLP component signaling, in which one or more PLP components are announced within a loop structure according to one or more aspects described herein. PLP ID field 801 may comprise an 8-bit field that may be consistent with a traditional system. NUM SUB MOD COD field 901 comprises a 4-bit field that defines the number of modulation (MOD) and code rate (COD) parameter combinations. Field 901 determines the length of the loop followed by PLP SUB MOD field 902, which is a field that indicates the modulation used by the associated PLP component. The modulation may be specified by signaling information per PLP in accordance with Table 2.

Table 2: Example of signaling format for the modulation signaled within

PLP SUB MOD-field

PLP SUB COD field 903 may comprise a field that indicates the code rate used by the associated PLP component and may be specified by signaling information in accordance with Table 3.

Table 3: Example of signaling format for the code rates signaled within

PLP_SUB_COD-field

PLP_SUB_NUM_BLOCKS field 904 may comprise a 10-bit field that indicates the number of FEC blocks contained in the current interleaving frame for the current PLP component. PLP SUBJvlOD CODJDX field 905 may comprise a field that indicates the index for the PLP component announced within the loop. PLP SUB MUX RATE field 906 may comprise a field that specifies the number of cells read from the input branch of the associated PLP component, in accordance with embodiment shown for multiplexer 302 as shown in Figure 3b. When the value is one for all PLP components (for example, as shown in Figure 3 a), field 906 may not be needed if the default value is used as previously discussed.

[58] Referring to Figure 9b, some exemplary embodiments include PLP component signaling, in which one or more PLP components are announced within a loop structure according to one or more aspects described herein. While similar to the exemplary embodiments depicted by Figure 9a, PLP PERM LENGTH field 910 specifies signalling information for the permutation length. Parameter 910 indicates the output dimension K of serial-to-parallel converter 404 as shown in Figure 4b. Because field 910 applies to all PLP components, parameter 910 is located outside the PLP component loop. Because all values may not suitable for K, the different bit combinations may be used to signal predefined permutation lengths, as shown in Table 4. Figure 10b shows an exemplary embodiment of PLP component signaling, where PLP PERM LENGTH 1010, which specifies the permutation length, may also be included in signalling for exemplary embodiments with a fixed number of PLP components (for example, two PLP components corresponding to high robustness and to low robustness). With some embodiments, PLP PERM LENGTH 1010 may comprise three bits and use the assignments shown in Table 4. However, fields 910 and 1010 may accommodate larger values of K.

Table 4: Example of signaling format for the permutation length signaled within

PLP_PERM_LENGTH-field

As previously discussed, the exemplary embodiments shown in Figures 10a and 10b support signaling for two PLP components, in which a first PLP component supports a high robustness and a second PLP component supports a low robustness. PLP_MOD_HI field 1001, PLP COD_HI field 1002, and PLP NUM BLOCKS HI field 1005 correspond to PLP_SUB_MOD field 902, PLP_SUB_COD field 903, and PLP SUB NUM BLOCKS field 904, respectively, for the high robustness PLP component. Similarly, PLP_MOD_LO field 1003, PLP_COD_LO field 1004, and PLP_NUM_BLOCKS_LO field 1006 correspond to PLP_SUB_MOD field 902, PLP_SUB_COD field 903, and PLP_SUB_NUM_BLOCKS field 904, respectively, for the low robustness PLP component.

[60] Figure 11 shows an exemplary apparatus 1100 that transmits content over wireless channel 1161 through antenna 1106 (may be external to the apparatus), in which PLP content 1154 includes a plurality of PLP components 1152 and 1153 according to one or more aspects described herein. Apparatus 1100 may be configured to transmit, encode, and process various types of transmissions including digital broadband broadcast transmissions that are based, for example, on the Digital Video Broadcast (DVB) standard, such as DVB-T2, DVB-T, DVB-H, or DVB-MHP or any future standards like for example the next generation handheld standard (DVB-NGH), through transmit communications interface 1103. Other digital transmission formats may alternatively be used to deliver content and information regarding availability of supplemental services. Additionally or alternatively, apparatus 1100 may be configured to transmit, encode, and process transmissions through communications interface 1103 that supports other types of communications media, including FM/AM and wireless local area network (WLAN) media.

[61] Apparatus 1100 may include controller 1104 connected to a user interface control and/or display (not explicitly shown) and the like. Controller 1104 may include one or more processors and memory (shown as separate memory 1105 in some embodiments) storing software.

[62] With some exemplary embodiments, component mapper 1101 maps transmitted service content 1151 (which may include one or more services) to PLP components 1152 and 1153. Mapper 1101 performs the mapping in accordance with mapping control 1157 from controller 1104 based on configuration information 1155.

[63] Formatter 1102 may perform interleaving, multiplexing, and permuting functionalities, as previously discussed with Figure 2, in accordance with format control 1156 from controller 1104 that is based on configuration information 1155. In addition, controller 1104 generates signaling data 1 158 that is indicative of the PLP component structure. Signaling data is then incorporated into the transmitted signal by communications interface 1 103 so that receiver 1200 can properly process the received signal.

[64] While the exemplary embodiment shown in Figure 1 1 shows only two PLP components, a different number of PLP components may be supported. Moreover, the PLP components may be incorporated on the same PLP or on different PLPs. While a PLP component may correspond to a service component, PLP components 1 152 and 1153 may be distinct from service components since a PLP component is characterized by its own robustness level (for example, modulation and coding) and may carry one or more service components.

[65] Computer executable instructions and data used by controller 1 104 and other components of apparatus 1100 may be stored in a storage facility such as memory 1105. Memory 1 105 may comprise any type or combination of read only memory (ROM) modules or random access memory (RAM) modules, including both volatile and nonvolatile memory such as disks. Software may be stored within memory 1105 to provide instructions to controller 1104 such that when the instructions are executed, controller 1104 and/or other components of apparatus 1100 are caused to perform various functions or methods such as those described herein. Software may include both applications and operating system software, and may include code segments, instructions, applets, pre-compiled code, compiled code, computer programs, program modules, engines, program logic, and combinations thereof. Computer executable instructions and data may further be stored on computer readable media including electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, CD-ROM, DVD or other optical disk storage, magnetic cassettes, magnetic tape, magnetic storage and the like.

[66] Figure 12 shows any exemplary apparatus 1200 that receives content over wireless channel 1 161 through antenna 1206 (may be external to the apparatus) from apparatus 1100, in which PLP content 1254 includes a plurality of PLP components 1 152 and 1 153 according to one or more aspects described herein. Apparatus 1200 may be configured to transmit, encode, and process various types of transmissions, as discussed above, through receive communications interface 1203. With some embodiments, apparatus 1200 may be incorporated in a mobile terminal.

[67] Apparatus 1200 may include controller 1204 connected to a user interface control and/or display (not explicitly shown) and the like. Controller 1204 may include one or more processors and memory (shown as separate memory 1205 in some embodiments) storing software. Computer executable instructions and data used by controller 1204 and other components of apparatus 1200 may be stored in a storage facility such as memory 1205 in a similar manner as described above for apparatus 1100.

[68] With some exemplary embodiments, component mapper 1201 maps PLP components 1252 and 1253 to received service content 1251 (which may include one or more services). Mapper 1201 performs the mapping in accordance with mapping control 1257 from controller 1 104 based on selection information 1255, which may be provided by a user.

[69] Re-formatter 1202 may perform de-interleaving, de-multiplexing, and permuting functionalities, as previously discussed with Figure 5, in accordance with re-format control 1256 from controller 1204 that is based on selection information 1255 and signaling data 1258.

[70] Although the above description, apparatus 1200 may comprise a mobile device, other devices or systems may include the same or similar components and perform the same or similar functions and methods. For example, a stationary computer may include the components or a subset of the components described above and may be configured to perform the same or similar functions as a mobile device and its components. Further examples might be set-top boxes, TV sets or even navigation devices.

[71] Figure 13 shows flow diagram 1300 for transmitting content over a wireless channel in which a PLP includes a plurality of PLP components according to one or more aspects described herein. In block 1301, a transmitting apparatus, for example apparatus 1 100 as previously discussed, receives a first partial data stream and a second partial data stream. The first partial data stream and the second partial data stream are processed according to a first modulation scheme and a first code rate and according to a second modulation scheme and a second code rate in blocks 1302 and 1303, respectively. In block 1304, the first and second partial data streams are transmitted over a communications channel on a same physical layer pipe. While flow diagram 1300 shows two partial data streams, embodiments may support two or more partial data streams.

[72] Figure 14 shows flow diagram 1400 for receiving content over a wireless channel in which a PLP includes a plurality of PLP components according to one or more aspects described herein. In block 1401, a receiving apparatus, for example apparatus 1200 as previously discussed, receives a data stream that contains a physical layer pipe over a communications channel. A first partial data stream and a second partial data stream are processed from the same physical layer pipe according to a first modulation scheme and a first code rate and according to a second modulation scheme and a second code rate in blocks 1402 and 1403, respectively.

[73] It should be understood that any of the method steps, operations, procedures or functions described herein may be implemented using one or more processors in combination with executable instructions that cause the processors and other components to perform the method steps, procedures or functions. As used herein, the terms "processor"/ "controller" and "computer" whether used alone or in combination with executable instructions stored in a memory or other computer- readable storage medium should be understood to encompass any of various types of well-known computing structures including but not limited to one or more microprocessors, special-purpose computer chips, field-programmable gate arrays (FPGAs), controllers, application-specific integrated circuits (ASICs), combinations of hardware/firmware/software, or other special or general-purpose processing circuitry.

[74] The methods and features recited herein may further be implemented through any number of computer readable media that are able to store computer readable instructions. Examples of computer readable media that may be used include RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, DVD or other optical disk storage, magnetic cassettes, magnetic tape, magnetic storage and the like. [75] Additionally or alternatively, in at least some embodiments, the methods and features recited herein may be implemented through one or more integrated circuits (ICs). An integrated circuit may, for example, be a microprocessor that accesses programming instructions or other data stored in a read only memory (ROM). In some such embodiments, the ROM stores programming instructions that cause the IC to perform operations according to one or more of the methods described herein. In at least some other embodiments, one or more the methods described herein are hardwired into an IC. In other words, the IC is in such cases an application specific integrated circuit (ASIC) having gates and other logic dedicated to the calculations and other operations described herein. In still other embodiments, the IC may perform some operations based on execution of programming instructions read from ROM or RAM, with other operations hardwired into gates and other logic of IC. Further, the IC may output image data to a display buffer.

[76] Although specific examples of carrying out the invention have been described, those skilled in the art will appreciate that there are numerous variations and permutations of the above-described systems and methods that are contained within the spirit and scope of the invention as set forth in the appended claims. Additionally, numerous other embodiments, modifications and variations within the scope and spirit of the appended claims will occur to persons of ordinary skill in the art from a review of this disclosure.

Claims

We Claim:

1. A method comprising:

receiving a first partial data stream and a second partial data stream;

processing, by a transmitting apparatus, the first partial data stream in accordance with a first modulation scheme and first code rate;

processing, by the transmitting apparatus, the second partial data stream in accordance with a second modulation scheme and a second code rate; and

transmitting the first partial data stream and the second partial data stream over a communications channel on a same physical layer pipe of a transmitted data stream.

2. The method of claim 1, further comprising:

multiplexing a first plurality of cells from the first partial data stream with a second plurality of cells from the second partial data stream.

3. The method of claim 2, further comprising:

permuting the first plurality of cells and the second plurality of cells.

4. The method of claim 3, wherein the same physical layer pipe is associated with an orthogonal frequency division multiplexing symbol and wherein a number of data carriers in the orthogonal frequency division multiplexing symbol is not divisible by a permutation block size used for the permuting.

5. The method of claim 1, further comprising:

separately interleaving the first partial data stream and the second partial data stream.

6. The method of claim 1, further comprising:

inserting signaling data for the first partial data stream and the second data stream into the transmitted data stream.

7. The method of claim 1, wherein the first partial data stream corresponds to a first service component of a service and the second partial data stream corresponds to a second service component of the service.

8. An apparatus comprising:

a multiplexer configured to multiplex a first plurality of cells from a first partial data stream and a second plurality of cells from a second partial data stream to form a multiplexed data stream;

a permutation circuit configured to permute multiplexed cells in the multiplexed data stream to form a permuted data stream; and

a communications interface configured to insert the permuted data stream into a physical layer pipe and configured to transmit a transmitted data stream that contains the physical layer pipe, wherein the first partial data stream is processed with a first modulation scheme and a first code rate and the second partial data stream is processed with a second modulation scheme and a second code rate.

9. The apparatus of claim 8, further comprising:

at least one interleaver configured to separately interleave the first partial data stream and the second partial data stream.

10. The apparatus of claim 8, wherein the communications interface is configured to insert signaling data for the first partial data stream and the second data stream into the transmitted data stream.

1 1. The apparatus of claim 8, wherein the permutation circuit further includes:

a serial-to-parallel converter configured to obtain the multiplexed data stream from the multiplexer;

a mapper configured to re-arrange cells presented by the serial-to-parallel converter; and

a parallel-to-serial converter configured to convert the re-arranged cells into the permuted data stream.

12. One or more computer readable media storing computer readable instructions that, when executed, cause an apparatus to:

receive a first partial data stream and a second partial data stream;

process the first partial data stream in accordance with a first modulation scheme and first code rate; process the second partial data stream in accordance with a second modulation scheme and a second code rate; and

transmit the first partial data stream and the second partial data stream over a communications channel on a same physical layer pipe of a transmitted data stream.

13. The one or more computer readable media of claim 12, wherein the computer readable instructions, when executed, further cause the apparatus to:

multiplex a first plurality of cells from the first partial data stream with a second plurality of cells from the second partial data stream.

14. The one or more computer readable media of claim 13, wherein the computer readable instructions, when executed, further cause the apparatus to:

permute the first plurality of cells and the second plurality of cells.

15. The one or more computer readable media of claim 12, wherein the computer readable instructions, when executed, further cause the apparatus to:

16. The one or more computer readable media of claim 12, wherein the computer readable instructions, when executed, further cause the apparatus to:

insert signaling data for the first partial data stream and the second data stream into the transmitted data stream.

17. An apparatus comprising:

at least one processor; and

at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform:

receive a first partial data stream and a second partial data stream;

process the first partial data stream in accordance with a first modulation scheme and first code rate;

process the second partial data stream in accordance with a second modulation scheme and a second code rate; and transmit the first partial data stream and the second partial data stream over a communications channel on a same physical layer pipe of a transmitted data stream.

18. The apparatus of claim 17, wherein the at least one memory further causes the apparatus to further perform:

19. The apparatus of claim 18, wherein the at least one memory further cause the apparatus to further perform:

permute the first plurality of cells and the second plurality of cells.

20. The apparatus of claim 17, wherein the at least one memory further cause the apparatus to further perform:

21. The apparatus of claim 17, wherein the at least one memory further cause the apparatus to further perform:

22. An apparatus comprising:

means for obtaining a first partial data stream and a second partial data stream;

means for processing the first partial data stream in accordance with a first modulation scheme and first code rate;

means for processing the second partial data stream in accordance with a second modulation scheme and a second code rate; and

means for transmitting the first partial data stream and the second partial data stream over a communications channel on a same physical layer pipe of a transmitted data stream.

23. The apparatus of claim 22, further comprising:

means for multiplexing a first plurality of cells from the first partial data stream with a second plurality of cells from the second partial data stream; and means for permuting the first plurality of cells and the second plurality of cells.

24. A method comprising:

receiving a received data stream containing a physical layer pipe over a communications channel, wherein the physical layer pipe comprises a first partial data stream and a second partial data stream;

processing, by a receiving apparatus, the first partial data stream from the physical layer pipe in accordance with a first modulation scheme and a first code rate; and

processing, by the receiving apparatus, the second partial data stream from the physical layer pipe in accordance with a second modulation scheme and a second code rate.

25. The method of claim 24, further comprising:

permuting a plurality of cells from the physical layer pipe to obtain a permuted data stream, wherein the permuting re-orders the plurality of cells to an original ordering.

26. The method of claim 24, further comprising:

de-multiplexing the permuted data stream to obtain the first partial data steam and the second partial data stream.

27. The method of claim 26, further comprising:

separately de-interleaving the first partial data stream and the second partial data stream.

28. The method of claim 24, further comprising:

extracting signaling data for the first partial data stream and the second partial data stream from the received data stream; and

processing the first partial data stream and the second partial data stream in accordance with the signaling data.

29. The method of claim 25, wherein the physical layer pipe is associated with an orthogonal frequency division multiplexing symbol and wherein a number of data carriers in the orthogonal frequency division multiplexing symbol is not divisible by a permutation block size used for the permuting.

30. The method of claim 24, wherein the first partial data stream corresponds to a first service component of a service and the second partial data stream corresponds to a second service component of the service.

31. An apparatus comprising:

a communications interface configured to receive a received data stream that contains a physical layer pipe, wherein the physical layer pipe comprises a first partial data stream and a second partial data stream;

a permutation circuit configured to permute a plurality of cells in the received data stream to obtain a permuted data stream; and

a de-multiplexer configured to de-multiplex the permuted data stream to obtain the first partial data steam and the second partial data stream, wherein the first partial data stream is processed in accordance with a first modulation scheme and a first code rate and the second partial data stream is processed in accordance with a second modulation scheme and a second code rate.

32. The apparatus of claim 31, further comprising:

at least one de-interleaver configured to separately de-interleave the first partial data stream and the second partial data stream.

33. The apparatus of claim 31, wherein the communications interface is configured to extract signaling data for the first partial data stream and the second data stream from the received data stream.

34. The apparatus of claim 31, wherein the permutation circuit further includes:

a serial-to-parallel converter configured to obtain the plurality of cells from the communications interface;

35. One or more computer readable media storing computer readable instructions that, when executed, cause an apparatus to:

receive a received data stream containing a physical layer pipe over a communications channel, wherein the physical layer pipe comprises a first partial data stream and a second partial data stream;

process the first partial data stream from the physical layer pipe in accordance with a first modulation scheme and a first code rate; and

process the second partial data stream from the physical layer pipe in accordance with a second modulation scheme and a second code rate.

36. The one or more computer readable media of claim 35, wherein the computer readable instructions, when executed, further cause the apparatus to:

permute a plurality of cells from the physical layer pipe to obtain a permuted data stream.

37. The one or more computer readable media of claim 36, wherein the computer readable instructions, when executed, further cause the apparatus to:

de-multiplex the permuted data stream to obtain the first partial data steam and the second partial data stream.

38. The one or more computer readable media of claim 37, wherein the computer readable instructions, when executed, further cause the apparatus to:

separately de-interleave the first partial data stream and the second partial data stream.

39. The one or more computer readable media of claim 35, wherein the computer readable instructions, when executed, further cause the apparatus to:

extract signaling data for the first partial data stream and the second partial data stream from the received data stream; and

process the first partial data stream and the second partial data stream in accordance with the signaling data.

An apparatus comprising:

at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform:

receive a data stream containing a physical layer pipe over a communications channel, wherein the physical layer pipe comprises a first partial data stream and a second partial data stream;

41. The apparatus of claim 40, wherein the at least one memory further cause the apparatus to further perform:

42. The apparatus of claim 41, wherein the at least one memory further cause the apparatus to further perform:

43. The apparatus of claim 42, wherein the at least one memory further cause the apparatus to further perform:

44. The apparatus of claim 40, wherein the at least one memory further cause the apparatus to further perform:

extract signaling data for the first partial data stream and the second partial data stream from the data stream; and

45. An apparatus comprising: means for receiving a data stream containing a physical layer pipe over a communications channel, wherein the physical layer pipe comprises a first partial data stream and a second partial data stream;

means for processing the first partial data stream from the physical layer pipe in accordance with a first modulation scheme and a first code rate; and

means for processing the second partial data stream from the physical layer pipe in accordance with a second modulation scheme and a second code rate.