CDMA spectral efficiency

The system spectral efficiency can be improved by radio resource management techniques, resulting in that a higher number of simultaneous calls and higher data rates can be achieved without adding more radio spectrum or more base station sites.

This article is about radio resource management specifically for direct-sequence spread spectrum (DS-CDMA) based cellular systems.

The objective of radio-resource management is typically to maximize the system spectral efficiency under constraint that the grade of service should be above a certain level.

Issues faced while deploying these techniques are the cost, upgrade requirements, hardware and software changes (which includes cell phone compatibility corresponding to the changes) to be made and the agreements to be approved from the telecommunication department.

Due to its large transmission power, the Common pilot channel (CPICH) probably consumes 15 to 20 percentage of the forward as well as the reverse link capacity[citation needed].

Another CDMA invention to provide a device and technique for improving a downlink phone capacity and receiving performance by gating an uplink DPCCH signal in a partial period of the power control group in a mobile communication system.

The CDMA radio configuration is defined as a combination of forward and reverse traffic channel transmission formats that are characterized by physical layer parameters such as data rates, error-correction codes, modulation characteristics, and spreading factors.

The forward link of a 3G code-division multiple-access (CDMA) system may become a limiting factor when the number of users increases maximal capacity.

This method uses aggregation of multiple quasi-orthogonal functions with a smaller constellation alphabet size for a single user with a joint multi-channel detector.

Each of these bounces can introduce phase shifts, time delays, attenuations, and even distortions that can destructively interfere with one another at the aperture of the receiving antenna.

With multiple signals there is a greater processing demand placed on the receiver, which can lead to tighter design requirements of the base station.

Typically, however, signal reliability is paramount and using multiple antennas is an effective way to decrease the number of drop-outs and lost connections.

This provides lower average data rates (ADRs) compared to EVRC, for a given voice quality.

There are some remote places where BTS signal penetrates but reverse link of mobile cannot reach back to the base station.

Solution is like reducing base station antenna height, down tilt, select lower gains, etc.