TABLE OF CONTENTS A radio channel is a communications channel that uses radio waves to transfer information from a source to a destination. A radio channel may transport one or many communication channels and communication circuits.
The EVDO system uses the same bandwidth size radio channels for IS-95 CDMA voice and EVDO data. To maximize the data transfer rate, the EVDO forward radio channel can use different types of modulation and different amounts of signal spreading (processing gain). The forward EVDO channel transmits at maximum power to one user at a time while the reverse EVDO channel uses precise power control and allows all the active (connected) users to transmit at the same time.
Radio channel bandwidth is the difference between the upper frequency limit and lower frequency limit of allowable radio transmission energy for a radio communication channel. The EVDO system uses the same 1.25 MHz radio channels for IS-95 CDMA and EVDO data only channels. Two radio channels are combined (paired) to form a full duplex (simultaneous two-way) communication channel.
Modulation is the process of changing the amplitude, frequency, or phase of a radio frequency carrier signal (a carrier) to change with the information signal (such as voice or data). Adaptive modulation is the process of dynamically adjusting the modulation type of a communication channel based on specific criteria (e.g. interference or data transmission rate).
The EVDO system uses quick adaptive modulation to optimize the maximum data transmission rate available for the conditions the EVDO device is...
