Segment-wise channel equalization based data estimation

Details Segment-wise channel equalization based data estimation Segment-wise channel equalization based data estimation

2002-05-22

2004-06-29

Chin, Stephen (Department: 2631)

Pulse or digital communications

Spread spectrum

Direct sequence

C375S148000, C375S260000, C375S340000, C370S479000

Reexamination Certificate

active

06757321

ABSTRACT:

BACKGROUND
The invention generally relates to wireless communication systems. In particular, the invention relates to data detection in a wireless communication system.
FIG. 1
is an illustration of a wireless communication system
10
. The communication system
10
has base stations
12
1
to
12
5
(
12
) which communicate with user equipments (UEs)
14
1
to
14
3
(
14
). Each base station
12
has an associated operational area, where it communicates with UEs
14
in its operational area.
In some communication systems, such as code division multiple access (CDMA) and time division duplex using code division multiple access (TDD/CDMA), multiple communications are sent over the same frequency spectrum. These communications are differentiated by their channelization codes. To more efficiently use the frequency spectrum, TDD/CDMA communication systems use repeating frames divided into time slots for communication. A communication sent in such a system will have one or multiple associated codes and time slots assigned to it. The use of one code in one time slot is referred to as a resource unit.
Since multiple communications may be sent in the same frequency spectrum and at the same time, a receiver in such a system must distinguish between the multiple communications. One approach to detecting such signals is joint detection. In joint detection, signals associated with all the UEs
14
, users, are detected simultaneously. Approaches for joint detection include zero forcing block linear equalizers (ZF-BLE) and minimum mean square error (MMSE) BLE. The methods to realize ZF-BLE or MMSE-BLE include Cholesky decomposition based and fast Fourier transform (FFT) based approaches. These approaches have a high complexity. The high complexity leads to increased power consumption, which at the UE
14
results in reduced battery life. Accordingly, it is desirable to have alternate approaches to detecting received data.
SUMMARY
Data is estimated of a plurality of received spread spectrum signals. The plurality of received communications are received in a shared spectrum. The received communications are sampled to produce a received vector. The received vector is processed to produce a plurality of segments. Each segment is processed separately to estimate data of the received communications.


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