US 8,619,676 B2 · Legacy cyclic shift delay (CSD) for orthogonal frequency division multiplexing (OFDM) signaling within multiple user, multiple access, and/or MIMO wireless communications

Abstract

Legacy cyclic shift delay (CSD) for use within multiple user, multiple access, and/or MIMO wireless communications. Appropriately designed CSD is applied to communications in wireless communication systems thereby ensuring a minimized power error difference between respective portions of a packet transmitted therein. Such respective portions of the packet may be portions of the packet's preamble. For example, the first and second portions may be a legacy short training field (L-STF) and a very high throughput short training field (VHT-STF). By applying such appropriately designed CSD to a packet, a wireless communication device receiving a signal corresponding to that packet need not perform extra or very significant backoff (e.g., with respect to a signal subsequent to automatic gain control (AGC) processing) thereby simplifying signal processing and potentially also reducing a total number of effective analog to digital converter (ADC) bits needed to represent a digitally sampled version of that signal.

Claims24

Dependent claims

A method for operating a wireless communication device, the method comprising:

generating a multi-user packet including a first portion being compliant with a first communication protocol and a second portion being compliant with a second communication protocol in accordance with a plurality of Cyclic Shift Delays (CSDs), each of the plurality of CSDs being a respective integer multiple of a time period, for minimizing difference between a first transmit power associated with the first portion and a second transmit power associated with the second portion;
and
via a plurality of antennae, transmitting a signal including the multi-user packet to a plurality of wireless communication devices such that each of the plurality of antennae transmitting at a respective time in accordance with a respective one of the plurality of CSDs.

An apparatus, comprising:

a baseband processing module to generate a multi-user packet including a legacy short training field (L-STF) being compliant in accordance with a first communication protocol and a very high throughput short training field (VHT-STF) being compliant in accordance with a second communication protocol in accordance with a plurality of Cyclic Shift Delays (CSDs) for minimizing difference between a first transmit power associated with the L-STF and the VHT-STF associated with the second portion and also for minimizing difference between the first transmit power associated with the L-STF and a second transmit power associated with a legacy long training field (L-LTF), a legacy signal field (L-SIG), and a very high throughput signal field (VHT-SIGA);
and
a plurality of antennae to transmit a signal including the multi-user packet to a plurality of wireless communication devices;
and wherein:
each of the plurality of CSDs being a respective integer multiple of 25 nano-seconds;
each of the plurality of antennae to transmit at a respective time in accordance a respective one of the plurality of CSDs;
and
each of plurality of CSDs being in a range of 0 nano-seconds to 200 nano-seconds, inclusive.

5 more elements

Dependencies are inferred from the claim text.

Legacy cyclic shift delay (CSD) for orthogonal frequency division multiplexing (OFDM) signaling within multiple user, multiple access, and/or MIMO wireless communications

Life of this patent

Legacy cyclic shift delay (CSD) for orthogonal frequency division multiplexing (OFDM) signaling within multiple user, multiple access, and/or MIMO wireless communications

Life of this patent

Abstract

Claims24