Framing for an adaptive modulation communication system

A method for conveying data in a downlink over a communication link, the method comprising:

• providing a downlink subframe with a time division multiplex (TDM) portion, including at least one TDM section, and a Time Division Multiple Access (TDMA) portion, including at least one TDMA section with an associated preamble;
• beginning the downlink subframe with a broadcast preamble;
• establishing a downlink map for the downlink subframe, the downlink map indicating one or more time positions within the downlink subframe where the at least one TDM section begins, and indicating one or more time positions within the downlink subframe where the at least one TDMA section begins;
• transmitting the downlink map in the downlink subframe after the broadcast preamble;
• and
• transmitting all TDM sections and all TDMA sections, along with each associated preamble, within the downlink subframe after transmitting the downlink map.

A time division duplexing (TDD) wireless communication method for use by a base station and a first terminal and a second terminal, wherein the base station transmits using a downlink subframe and the terminals transmit using an uplink subframe, both on the same channel, wherein the downlink subframe includes a broadcast preamble and a Time Division Multiple Access (TDMA) portion, and wherein the TDMA portion includes a first modulation/forward error correction (PHY) mode with an associated preamble which is only intended for the first terminal, and a second PHY mode with an associated preamble which is only intended for the second terminal, the method comprising:

• transmitting a broadcast preamble from a base station to a first terminal and a second terminal during a downlink subframe;
• synchronizing the first and the second terminals to the base station based on the broadcast preamble;
• transmitting a first preamble by the base station using a smart antenna to only the first terminal after transmitting the broadcast preamble, wherein the first preamble is associated with a first PHY mode;
• re-synchronizing the first terminal with the base station based on the first preamble transmitted by the base station;
• transmitting modulated data from the base station using the smart antenna to only the first terminal during the downlink subframe using the first PHY mode after the first terminal is synchronized with the base station;
• transmitting a second preamble from the base station using the smart antenna to only the second terminal after transmitting the modulated data to the first terminal, wherein the second preamble is associated with a second PHY mode;
• and
• re-synchronizing the second terminal with the base station based on the second preamble transmitted by the base station.

A frequency division duplexing (FDD) wireless communication system including a base station, at least one full-duplex terminal, and at least one half-duplex terminal, wherein the base station transmits using a downlink subframe on a first channel and the full-duplex and half-duplex terminals transmit using an uplink subframe on a second channel, wherein the downlink subframe includes a broadcast preamble, a time division multiplex (TDM) portion, and a Time Division Multiple Access (TDMA) portion, and wherein the TDMA portion includes at least one modulation/forward error correction (PHY) mode with an associated preamble, both of which are intended for the at least one half-duplex terminal, the system comprising:

• at least one half-duplex terminal configured to alternate between transmitting on a first channel and receiving on a second channel;
• at least one full-duplex terminal configured to transmit on the first channel while receiving on the second channel;
• and
• a base station configured to transmit a broadcast preamble to the half-duplex terminal and the full-duplex terminal during a TDM portion of a downlink subframe and to transmit a preamble during a TDMA portion of the downlink subframe, wherein the half-duplex terminal synchronizes with the base station based on the broadcast preamble and re-synchronizes with the base station based on the preamble.

A time division duplexing (TDD) wireless communication system including a base station, a first terminal, and a second terminal, wherein the base station transmits during a downlink subframe and the first and second terminals transmit during an uplink subframe, both on a same channel, wherein the downlink subframe includes a broadcast preamble and a Time Division Multiple Access (TDMA) portion, and wherein the TDMA portion includes a first modulation/forward error correction (PHY) mode with an associated preamble which is only intended for the first terminal, and a second PHY mode with an associated preamble which is only intended for the second terminal, the system comprising:

• a first terminal configured to alternate between transmitting and receiving on a first channel;
• a second terminal configured to alternate between transmitting and receiving on the first channel;
• a base station configured to transmit a broadcast preamble to the first and second terminals during a TDM portion of a downlink subframe and to transmit a preamble during a TDMA portion of the downlink subframe, wherein the first terminal synchronizes with the base station based on the broadcast preamble and re-synchronizes with the base station based on the preamble;
• and
• a smart antenna coupled to the base station and configured to transmit the preamble to only the first terminal during the TDMA portion of the downlink subframe.

A method for scheduling modulation/forward error correction (PHY) modes for a frequency division duplex (FDD) communication system which includes a plurality of terminals and a base station, both configured to communicate using adaptive modulations in a downlink subframe and an uplink subframe, with each of the plurality of terminals having an associated preferred downlink PHY mode, D1, D2, . . . DN, wherein D1 is a most robust modulation and DN is a least robust modulation, and wherein each of the plurality of terminals and their associated preferred downlink PHY mode have an associated uplink PHY mode, U1, U2, UN, and wherein U1 is associated with the plurality of terminals that have the preferred downlink PHY mode D1, and wherein UN is associated with the plurality of terminals that have the preferred downlink PHY mode DN, such that a number of downlink map entries does not exceed 2N+1, the method comprising:

• grouping the plurality of terminals based on preferred downlink PHY modes;
• allocating uplink bandwidth in an uplink subframe such that the plurality of terminals are put in order of their preferred downlink PHY modes, from a second most robust preferred downlink PHY mode and continuing in order of decreasing robustness with a most robust preferred downlink PHY mode last;
• allocating the plurality of terminals that use a D1 PHY mode to begin at a start of a downlink subframe;
• if a time duration of the D1 PHY mode is less than a time duration of a U2 PHY mode, allocating bandwidth of the downlink subframe to the plurality of terminals that use a D2 PHY mode, beginning at a time that the U2 PHY mode ends;
• if the time duration of the D1 PHY mode is greater than or equal to the time duration of the U2 PHY mode, allocating bandwidth of the downlink subframe to the plurality of terminals that use the D2 PHY mode, beginning at an end of the D1 PHY mode;
• if a time duration of the D2 PHY mode is less than a time duration of a U3 PHY mode, allocating bandwidth of the downlink subframe to the plurality of terminals that use a D3 PHY mode, beginning at a time that the U3 PHY mode ends;
• if the time duration of the D2 PHY mode is greater than or equal to the time duration of the U3 PHY mode, allocating bandwidth of the downlink subframe to the plurality of terminals that use the D3 PHY mode, beginning at an end of the D2 PHY mode;
• if the time duration of the D3 PHY mode is greater than the sum of a time duration of a U4 PHY mode, a U5 PHY mode, and a U1 PHY mode, segmenting the plurality of terminals that use the D3 PHY mode and inserting the segments into any gaps in the downlink subframe;
• if a time duration of the D3 PHY mode is less than a time duration of the U4 PHY mode, allocating bandwidth of the downlink subframe to the plurality of terminals that use a D4 PHY mode, beginning at a time that the U4 PHY mode ends;
• if the time duration of the D3 PHY mode is greater than or equal to the time duration of the U4 PHY mode, allocating bandwidth of the downlink subframe to the plurality of terminals that use the D4 PHY mode, beginning at an end of the D3 PHY mode;
• if a time duration of the D4 PHY mode is less than a time duration of the U5 PHY mode, allocating bandwidth of the downlink subframe to the plurality of terminals that use a D5 PHY mode, beginning at a time that the U5 PHY mode ends;
• if the time duration of the D4 PHY mode is greater than or equal to the time duration of the U5 PHY mode, allocating bandwidth of the downlink subframe to the plurality of terminals that use the D5 PHY mode, beginning at an end of the D4 PHY mode;
• if the time duration of the plurality of terminals that use the D5 PHY mode is longer in duration than a combined time duration of the U1 PHY mode and gaps that are not aligned with the U5 PHY mode, rearranging allocated downlink bandwidth of the downlink subframe to accommodate a remainder of the D5 PHY mode such that the remainder is not aligned with the U5 PHY mode;
• and
• if the time duration of the plurality of terminals that use the D5 PHY mode is shorter in duration than the combined time duration of the U1 PHY mode and the gaps that are not aligned with the U5 PHY mode, allocating bandwidth of the downlink subframe to the plurality of terminals that use the D5 PHY mode beginning at the end of the D4 PHY mode and also interleaved in the gaps in the downlink subframe.

A method for scheduling modulation/forward error correction (PHY) modes for a frequency division duplex (FDD) communication system which includes a plurality of terminals and a base station, both configured to communicate using adaptive modulations in a downlink subframe and an uplink subframe, with each of the plurality of terminals having an associated preferred downlink PHY mode, D1, D2, . . . DN, wherein D1 is a most robust modulation and DN is a least robust modulation, and wherein each of the plurality of terminals and their associated preferred downlink PHY mode have an associated uplink PHY mode, U1, U2, UN, and wherein U1 is associated with the plurality of terminals that have the preferred downlink PHY mode D1, and wherein UN is associated with the plurality of terminals that have the preferred downlink PHY mode DN, such that a number of downlink map entries does not exceed 2N+1, the method comprising:

• grouping the plurality of terminals based on preferred downlink PHY modes;
• allocating uplink bandwidth in an uplink subframe such that the plurality of terminals are put in order of their preferred downlink PHY modes, from a second most robust preferred downlink PHY mode and continuing in order of decreasing robustness with a most robust preferred downlink PHY mode last;
• allocating the plurality of terminals that use a D1 PHY mode to begin at a start of a downlink subframe;
• if a time duration for the plurality of terminals that have a DN PHY mode is less than a time duration for the plurality of terminals that are assigned to a UN+1 PHY mode, allocating bandwidth of the downlink subframe to the plurality of terminals that use the DN PHY mode, beginning at a time that a UN PHY mode ends;
• if the time duration for the plurality of terminals that have the DN PHY mode is greater than or equal to the time duration for the plurality of terminals that are assigned to the U+1 PHY mode, allocating bandwidth of the downlink subframe to the plurality of terminals that use the DN PHY mode, beginning at an end of a DN−1 PHY mode;
• if the time duration of the plurality of terminals that have the DN PHY mode is longer in duration than a combined time duration of a U1 PHY mode and gaps that are not aligned with the UN PHY mode, rearranging downlink bandwidth of the downlink subframe to accommodate a remainder of the DN PHY mode such that the remainder is not aligned with the UN PHY mode;
• and
• if the time duration of the plurality of terminals that have the DN PHY mode is shorter in duration than the combined time duration of the U1 PHY mode and the gaps that are not aligned with the UN PHY mode, allocating bandwidth of the downlink subframe to the plurality of terminals that use the DN PHY mode, beginning at the end of the DN−1 PHY mode and also interleaved in the gaps in the downlink subframe.

A frequency division duplexing (FDD) wireless communication method for use by a base station and a first terminal and a second terminal, wherein the base station transmits using a downlink subframe on a first channel and the terminals transmit using an uplink subframe on a second channel, wherein the downlink subframe includes a broadcast preamble and a Time Division Multiple Access (TDMA) portion, and wherein the TDMA portion includes a first modulation/forward error correction (PHY) mode with an associated preamble which is only intended for the first terminal, and a second PHY mode with an associated preamble which is only intended for the second terminal, the method comprising:

• transmitting a broadcast preamble from a base station to a first terminal and a second terminal during a downlink subframe on a first channel;
• synchronizing the first and the second terminals to the base station based on the broadcast preamble;
• transmitting a first preamble by the base station using a smart antenna on the first channel to only the first terminal after transmitting the broadcast preamble, wherein the first preamble is associated with a first PHY mode;
• re-synchronizing the first terminal with the base station based on the first preamble transmitted by the base station;
• transmitting modulated data from the base station using the smart antenna on the first channel to only the first terminal during the downlink subframe using the first PHY mode after the first terminal is synchronized with the base station;
• transmitting a second preamble by the base station using the smart antenna on the first channel to only the second terminal after transmitting the modulated data to the first terminal, wherein the second preamble is associated with a second PHY mode;
• and
• re-synchronizing the second terminal with the base station based on the second preamble transmitted by the base station.