Assigning physical channels to time slots using a...

Details Assigning physical channels to time slots using a... Assigning physical channels to time slots using a...

2001-05-14

2004-03-30

Duong, Frank (Department: 2666)

Multiplex communications

Communication over free space

Repeater

C370S335000, C370S342000, C370S441000, C455S452200

Reexamination Certificate

active

06714523

ABSTRACT:

BACKGROUND
The invention generally relates to wireless hybrid time division multiple access/code division multiple access communication systems. In particular, the invention relates to resource management in such systems.
FIG. 1
depicts a physical layout of a wireless communication system. The system has a plurality of base stations
20
. Each base station
20
communicates with user equipments (UEs)
22
in its operating area or cell
23
. Communications transmitted from the base stations
20
to the UEs
22
are referred to as downlink communications and communications transmitted from the UEs
22
to the base stations
20
are referred to as uplink communications.
A network perspective of a wireless communication system is shown in FIG.
2
. Each node-B
24
within the system wirelessly communicates with associated UEs
22
or users. Each node-B
24
has a single site controller (SC)
34
associated with either a single or multiple base stations
20
. A group of node-Bs
24
is connected to a radio network controller (RNC)
28
1
. To transfer communications between RNCs
28
, an interface between the RNCs (IUR)
26
is utilized. Each RNC
28
is connected to a mobile switching center (MSC)
30
which in turn is connected to the core network
32
.
In code division multiple access (CDMA) communication systems, multiple communications can be sent over the same spectrum simultaneously. The multiple communications are distinguished by their codes. In hybrid time division multiple access (TDMA)/CDMA communication systems, such as time division duplex (TDD) using CDMA (TDD/CDMA) communication systems, the spectrum is time divided into repeating frames having time slots, such as fifteen time slots. In such systems, communications are sent in selected time slots using selected codes. A physical channel is defined as one code in one time slot. The use of a single code in a single time slot with a spreading factor of sixteen is referred to as a resource unit. Based on the type of service being provided to a user (UE
22
) in the system, one or multiple physical channels may be assigned to support the users uplink and downlink communications.
The assignment of physical channels to users in such a system is a complex problem. Each physical channel used in a time slot creates interference with respect to other channels used in that time slot. Accordingly, it is desirable to choose time slots as to minimize interference.
However, there are drawbacks to choosing time slots solely based on interference. A UE
22
communicating using less time slots typically will have a lower power consumption. By stacking codes in a smaller number of time slots, other time slots are left open for new users. Additionally, some UEs
22
may be only able to use a few time slots, such as one or two.
Accordingly, it is desirable to have effective resource management in hybrid TDMA/CDMA communication systems.
SUMMARY
A physical channel of a user service is provided for assignment to a set of time slots in a hybrid time division multiple access/code division multiple access wireless communication system. A measure of interference is determined for each of the set of time slots. A fragmentation parameter is provided. The fragmentation parameter represents a preference for fragmenting user service physical channels over time slots. The user service physical channel is assigned to one of the set of time slots using the measured interference associated with each of the set of time slots and the fragmentation parameter.


REFERENCES:
patent: 5260967 (1993-11-01), Schilling
patent: 5481533 (1996-01-01), Honig et al.
patent: 5533013 (1996-07-01), Leppanen
patent: 5963865 (1999-10-01), Desgagne et al.
patent: 6519240 (2003-02-01), Dillinger et al.
TS C104 V2.1.0, China Wireless Telecommunication Standard, pp. 1-11, 1999.*
3G TR 25. 922, Technical Specification Group Radio Access Network, pp. 1-57, 1999.*
Anderlind, Resource Allocation in Multi-Service Wireless Access Networks, Thesis, pp. 1-148, Royal Institute of Technology, Sweden, Oct. 1997.*
El-Khamy et. al. “Wireless Portable Communication Using Pre-Rake CDMA/TDD/QPSK Systems With Different Combining Techniques And Imperfect Channel Estimation” IEEE, May 1997, pp. 529-533.
Povey, TDD-CDMA “Extension to FDD-CDMA Based Third Generation Cellular System” IEEE, Aug. 1997, pp. 813-817.
Mihailescu et al., “Dynamic Resource Allocation For Packet Transmission In UMTS TDD TD-CDMA Systems” IEEE. Feb. 1999, pp. 1737-1741.
Qingyu et al., “An Analysis of the Interference in the TDD-CDMA System” IEEE, Aug. 2000, pp. I-333-I-337.
Haas, et al. “A Novel Channel Assignment Approach in TDMA/CDMA-TDD Systems” IEEE, Jan. 2001, pp. E-142-E-146.
Zhang et al., “A Dynamic Channel Allocation Algorithm in TDD Mode CDMA Systems” IEEE, Aug. 2001, pp. 385-388.

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