Programmable transmitter

• US 20060291583A1
• Filed: 06/24/2005
• Published: 12/28/2006
• Est. Priority Date: 06/24/2005
• Status: Active Grant

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Moorti, R. Tushar, Hammerschmidt, Joachim S., Kodavati, Venkat, Edwards, Bruce E., Trachewsky, Jason A., Wagner, Andrew, Su, Ling
• Granted Patent: US 7,535,972 B2
• Time in Patent Office: Days
• US Class Current: 375/295
• CPC Class Codes: H04B 7/04 using two or more spaced independent antennas
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals

Abstract

A programmable transmitter generates a frame in a frame format according to one of a plurality of operating modes using a frame structure table storing a respective frame format for each of the operating modes. The transmitter includes a frame structure engine that receives a mode selection signal indicative of a select operating mode, and accesses the frame structure table to determine the frame format of the select operating mode. The frame structure engine produces a control signal to a frame generator to control the generation of a frame in the frame format of the select operating mode.

Claims

1. A transmitter within a radio transceiver for generating a frame in a frame format according to one of a plurality of operating modes, the transmitter comprising:

a frame structure table for storing a respective frame format for each of the plurality of operating modes;

a frame structure engine operably coupled to receive a mode selection signal indicative of a select operating mode, wherein the frame structure engine is operable to access the frame structure table to determine the frame format of the select operating mode and produce a control signal to control frame generation in the frame format of the select operating mode; and

a frame generator operably coupled to receive the control signal and to generate a frame in the frame format of the select operating mode in response to the control signal.

2. The transmitter of claim 1, wherein the frame generator further comprises:

a tone mapper operably coupled to map a data sequence into symbols to be included in the frame in response to the control signal; and

an inverse fast Fourier transform (IFFT) module operably coupled to convert the symbols from a frequency domain to a time domain to produce a plurality of tones for transmitting the frame.

3. The transmitter of claim 2, further comprising:

a scrambler operably coupled to receive an outgoing digital signal including data and to scramble the outgoing digital signal to produce scrambled data;

a channel encoder operably coupled to encode the scrambled data to produce encoded data;

an interleaver operably coupled to interleave the encoded data to produce interleaved data; and

a demultiplexer operably coupled to divide the interleaved data into two or more data streams, the data sequence input to the tone mapper including one of the two or more data streams.

4. The transmitter of claim 2, further comprising:

a space time encoding module operably coupled to space-time encode the plurality of tones to produce a plurality of space-time encoded subcarriers;

a digital module operably coupled to filter the plurality of space-time encoded subcarriers to produce digital baseband signals;

a digital to analog converter operably coupled to convert the digital baseband signals into analog baseband signals;

an in-phase/quadrature modulator operably coupled to mix the analog baseband signals with a local oscillation to produce up-converted RF signals; and

a power amplifier operably coupled to amplify the up-converted RF signals to produce amplified up-converted RF signals.

5. The transmitter of claim 2, wherein the IFFT module is operable to convert the symbols from the frequency domain to the time domain to produce the plurality of tones by utilizing coded orthogonal frequency division multiplexing (OFDM) with sixty-four or one hundred twenty eight point IFFT.

6. The transmitter of claim 2, wherein the frame comprises frame segments, and wherein the frame structure table includes a respective entry for each of the frame segments of the frame for the select operating mode.

7. The transmitter of claim 6, wherein each entry includes a segment type and a pointer for the segment type for each transmit antenna.

8. The transmitter of claim 7, wherein the segment type includes a data type corresponding to a data segment in the frame, and wherein the frame is sent over a plurality of tones in a channel, and further comprising:

data tone map tables for storing respective operating mode data segment formats of the data segment for each of the operating modes, the pointer in the entry of the frame structure table for the data type pointing to one of the operating mode data segment formats for the select operating mode;

wherein each of the operating mode data segment formats includes respective tone data segment formats for each of the tones, each of the plurality of tones is one of a data tone, a pilot tone or an empty tone and each of the tone data segment formats is one of a data format for each of the data tones, a pilot format for each of the pilot tones or an empty format for each of the empty tones.

9. The transmitter of claim 8, wherein the segment type further includes a signal-field type corresponding to a signal-field segment in the frame, and further comprising:

signal tone map tables for storing operating mode signal-field segment formats of the signal-field segment for each of the operating modes, the pointer in the entry of the frame structure table for the signal-field type pointing to one of the tone signal-field segment formats for the select operating mode;

wherein the operating mode signal-field segment formats each includes a respective tone signal-field segment format for each of the tones and each of the tone signal-field segment formats is either a signal data format for each of the data tones, the pilot format for each of the pilot tones or the empty format for each of the empty tones.

10. The transmitter of claim 9, wherein the data sequence input to the tone mapper is a known data stream, and wherein the signal data format indicates a rotation of the known data stream.

11. The transmitter of claim 9, wherein the pilot format comprises one of a static pilot sequence input to the tone mapper or a pilot format signal for generating a dynamic pilot sequence, and further comprising:

a pilot table for storing pilot sequences;

a pseudonoise generator for generating a pseudorandom sequence; and

a pilot scrambling engine operably coupled to receive the pilot format signal from one of the data tone map table and the signal tone map table, access the pilot table to read out one of the pilot sequences and receive the pseudorandom sequence from the pseudonoise generator based on the pilot format signal, wherein the pilot scrambling engine is further operable to multiply the pseudorandom sequence and the one of the pilot sequences to generate the dynamic pilot sequence.

12. The transmitter of claim 11, wherein the pilot scrambling engine comprises a pilot sequence engine operably coupled to receive the pilot format signal and read out the one of the pilot sequences from the pilot table, and wherein a first value of the pilot format signal causes the pilot sequence engine to read out a current pilot sequence from the pilot table to produce the dynamic pilot sequence and a second value of the pilot format signal triggers the pilot sequence engine to read out a next pilot sequence following the first pilot sequence from the pilot table to produce the dynamic pilot sequence.

13. The transmitter of claim 12, wherein the pilot table comprises a respective pilot table for each antenna of the transmitter, and wherein the pilot scrambling engine comprises a respective pilot sequence engine for each antenna of the transmitter, the pilot scrambling engine multiplying the respective one of the pilot sequences read out from each of the respective pilot tables with the pseudorandom sequence to produce respective dynamic pilot sequences for each of the antennas.

14. The transmitter of claim 12, wherein the pilot scrambling engine is further operable to receive a first pseudorandom sequence from the pseudonoise generator based on a first value of the pilot format signal to produce the dynamic pilot sequence and to trigger the pseudonoise generator to receive a second pseudorandom sequence from the pseudonoise generator based on a second value of the pilot format signal to produce the dynamic pilot sequence.

15. The transmitter of claim 7, wherein the segment type includes a frequency domain training type corresponding to a training segment of the frame, and further comprising:

a training table for storing training sequences of the training segment of the frame for each of the operating modes, the training sequences including a respective tone symbol for each of the tones;

wherein the pointer in the entry of the frame structure table for the frequency domain training type points to one of the training sequences in the training table per antenna.

16. The transmitter of claim 15, wherein each entry in the frame structure table further comprises a start field indicating a starting sample, a length field indicating a length of the training segment of the frame for the respective entry and a scale field indicating a scaling factor for the training segment of the frame.

17. The transmitter of claim 16, wherein the training table is a training tone map table in the frequency domain, and wherein the data sequence input to the tone mapper includes the one of the training sequences pointed to by the pointer, and wherein the frame generator further comprises:

a readout module operably coupled to receive the control signal from the frame structure engine, and to receive the plurality of tones from the IFFT, each including a respective time domain tone symbol that collectively forms an orthogonal frequency division multiplexed (OFDM) symbol containing samples, the control signal indicating the starting sample in the OFDM symbol, the length for the training segment of the frame and the scaling factor, and wherein the symbol readout module is operable to generate a complete training sequence of OFDM symbols for the training segment of the frame using the starting sample and the length and to scale the complete training sequence of OFDM symbols by the scaling factor to produce the training segment of the frame.

18. The transmitter of claim 16, wherein the segment type comprises a time domain training type corresponding to a training segment of the frame, and further comprising:

a sequence table for storing time domain training sequences for the time domain training type, each time domain training sequence including a time domain tone symbol for ones of the tones that collectively form an orthogonal frequency division multiplexed (OFDM) symbol containing samples, the pointer in the entry of the frame structure table for the time domain training type pointing to one of the training sequences in the sequence table; and

a sequence engine operably coupled to receive the control signal from the frame structure engine, the control signal including the starting sample, the length and the scaling factor for the training sequence segment of the frame, and wherein the sequence engine is operable to generate a complete training sequence of OFDM symbols for the training segment of the frame using the starting sample and the length and to scale the complete OFDM symbol by the scaling factor to produce the training segment of the frame.

19. The transmitter of claim 7, wherein each entry in the frame structure table further includes a pointer for each antenna of the transmitter, a start field indicating a starting sample of the frame segment for each antenna of the transmitter, a length field indicating a length of the frame segment of the frame for the respective entry, a scale field indicating a scaling factor for the frame segment of the frame for each antenna of the transmitter and an active field indicating whether the frame segment is included in the frame sent on each antenna of the transmitter.

20. The transmitter of claim 19, wherein the entry in the frame structure table further includes an nJump field having an nJump index that identifies a next entry corresponding to a next frame segment to generate an nBurst frame.

21. The transmitter of claim 1, wherein the plurality of operating modes comprises at least one of:

20 MHz channels for a 2.4 to 2.5 GHz frequency band;

20 and 40 MHz channels for a 4.9 to 5.850 GHz frequency band;

multiple MIMO transmit modes utilizing two, three, or four transmit paths;

data rates up to at least 480 Megabits per second (Mbps); and

frames including at least 4096 octets.

22. The transmitter of claim 1, further comprising:

a memory for storing the frame structure tables.

23. The transmitter of claim 1, further comprising:

a processor operable to generate the frame structure tables during a configuration period of the transmitter and store the frame structure tables in the memory.

24. A method for generating a frame for transmission over the air interface in a frame format according to one of a plurality of operating modes, comprising the steps of:

providing a frame structure table containing a respective frame format for each of the plurality of operating modes;

receiving a mode selection signal indicative of a select operating mode;

determining the frame format of the select operating mode from the frame structure table; and

generating a frame in the frame format of the select operating mode.