Despreading-on-demand for use in spread spectrum receivers

Abstract

A flexible and resource-efficient despreading-on-demand (DoD) technique is described where only channels that actually contain data to be despread are despread, and only a single despreading operation need be performed using the actual spreading factor associated with that data. In one example, the data portion of the received signal is buffered for a frame so that an associated transport format, including the actual spreading factor, can be determined before the data is despread. The data is buffered in a memory at a first rate and then subsequently read out at a second rate that is considerably faster than the first rate. The fast data read-out allows despreading at a high rate so that the despread data symbols from the buffered frame are available for further processing shortly after the last sample belonging to the frame has been received.

Description

technical field [0001] The technical field relates to mobile radio communications, and in particular to despreading received signals in code division multiple access (CDMA) based communication systems. Background technique [0002] figure 1 An example mobile communication network 10 is shown. A radio access network (RAN) 12 is coupled to one or more core networks 14, which in turn are coupled to one or more external networks 16, such as the Internet, PSTN, ISDN, and the like. The radio access network 12 includes, for example, one or more radio network controllers (RNCs) 18, which communicate signaling and / or traffic to each other. Each RNC 18 controls one or more radio base stations (BS) 20 . A base station may also be referred to as a Node B or access point. Each base station 20 transmits information over an "air" or wireless interface via various downlink radio channels in one or more corresponding coverage areas called cells. Each base station 20 also receives uplink...

AI Technical Summary

Problems solved by technology

Like the format shown in Figure 3, the transport format shown in Figure 4 suffers from the following drawback: the spreading factor for the DPDCH carried on the E-DPCCH is not explicitly available until the entire E-DPCCH subframe is received and its demodulation

This situation creates a buffering requirement that may be 50% larger, which means that a properly sized larger buffer must be provided

Images