Methods and apparatus for communication with time-division duplexing

In a multi-cell wireless communication network, a base station capable of generating and transmitting signals to one or more mobile stations, the base station comprising:

• a transmitter for generating a plurality of signal transmission frames, wherein:
• each transmission frame is partitioned into a plurality of subframes;
• each subframe is further divided into a plurality of time-slots having a plurality of orthogonal frequency division multiplexing (OFDM) symbols, the OFDM symbols generated by randomizing frequency-domain data before modulating the randomized data to produce modulated data symbols, inserting training symbols, mapping the modulated data symbols and training symbols to frequency-domain subcarriers, and converting the frequency-domain subcarriers to time-domain signals through an inverse Fast Fourier Transform (FFT);
• at least one special downlink period (SDP) is inserted in a transmission frame for the base station to broadcast control information, including cell identity information;
• and
• a controller for adaptively controlling signal generation to facilitate data transmission for two or more application services by switching between configurations for frequency-domain randomization, including:
• a first frequency-domain randomization configuration that is different among individual cells, wherein the frequency-domain randomization configuration is controlled by a cell identity of each cell and is used to facilitate data unicasting;
• and
• a second frequency-domain randomization configuration that is the same for multiple cells, wherein the second frequency-domain randomization configuration is used to facilitate data broadcasting;
• wherein the transmitter is further configured to transmit the plurality of downlink signal transmission frames as a downlink signal to one or more mobile stations.

A method of transmitting and receiving signals in a multi-cell wireless communication network by a mobile station, the method comprising:

• generating a plurality of transmission frames by:
• partitioning each transmission frame into a plurality of subframes and dividing each subframe into a plurality of time-slots;
• and
• inserting at least one special uplink period (SUP) into a transmission frame for the mobile station to carry out radio functions, including initial ranging during power up and hand-off, periodic ranging, bandwidth request, and/or channel sounding to assist downlink scheduling or advanced antenna technologies;
• transmitting the plurality of transmission frames to a base station;
• and
• receiving downlink signals from the base station, the received signals including a plurality of receiving frames, wherein each receiving frame is partitioned into a plurality of receiving subframes, and wherein each receiving subframe contains a plurality of orthogonal frequency division multiplexing (OFDM) symbols, wherein the OFDM symbols were generated by randomization of frequency-domain data before modulation of the randomized data to produce modulated data symbols, mapping of the modulated data symbols and inserted training symbols to frequency-domain subcarriers, and conversion of the frequency-domain subcarriers to time-domain signals through an inverse Fast Fourier Transform (FFT), and wherein at least two kinds of configurations for frequency-domain randomization were employed to facilitate transmission of two or more application services, the configurations for frequency-domain randomization including:
• a first frequency-domain randomization configuration that is different among individual cells, wherein the first frequency-domain randomization configuration is controlled by a cell identity of each cell and is used to facilitate data unicasting;
• and
• a second frequency-domain randomization configuration that is the same for multiple cells, wherein the second frequency-domain randomization configuration is used to facilitate data broadcasting.