Intelligent uplink SCDMA scheduling incorporating polarization and/or spatial information to determine SCDMA code set assignment

• US 20040071115A1
• Filed: 10/11/2002
• Published: 04/15/2004
• Est. Priority Date: 10/11/2002
• Status: Abandoned Application

• Current Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Bevan, David Damian Nicholas, Hashem, Bassam, Earnshaw, Mark, Robson, Julius G.
• Application Number:
  US10/268,906
• Publication Number:
  US 20040071115A1
• Time in Patent Office: Days
• US Class Current: 370/335
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity
• CPC Class Codes: H04J 13/0044 OVSF [orthogonal variable spreading factor]
• CPC Class Codes: H04J 13/20 having an orthogonal variable spreading factor [OVSF]

Abstract

A method for synchronous code division multiple access (SCDMA) scheduling including intelligent uplink SCDMA scheduling that incorporates polarization and/or spatial information to determine SCDMA code set assignment. The method includes scheduling algorithms to reduce observed interference and thus allow for a potentially significant increase in uplink capacity. This allows more terminals to be accommodated within a single site (i.e., higher sustainable user density) and/or a reduction in the number of base stations that must be deployed in order to cover a given area. This present invention is applicable to any high-speed wireless evolution SCDMA-based data system that would require highly efficient and optimized scheduling algorithms.

Claims

1. A method for uplink SCDMA scheduling within a telecommunications system capable of separating users, said method comprising:

a) determining a characteristic of a first user;

b) determining a related characteristic of a second user;

c) comparing said characteristic to said related characteristic to verify orthogonality therebetween;

d) upon determination of orthogonality, assigning said first user and said second user differing SCDMA code sets;

e) upon determination of non-orthogonality, assigning said first user and said second user an identical SCDMA code set.

2. The method as claimed in claim 1, wherein said characteristic and said related characteristic are polarization information.

3. The method as claimed in claim 1, wherein said characteristic and said related characteristic are spatial information.

4. The method as claimed in claim 2, wherein said determining steps further includes

f) providing an arbitrary pair of orthogonal axes, each of which corresponds to one of two SCDMA code sets,

g) projecting a polarization vector of both said first user and said second user onto said pair of orthogonal axes,

h) calculating magnitudes of said polarization vectors,

i) identifying a larger one of said magnitudes,

j) assigning said first user or second user related to said larger one of said magnitudes to one of said two SCDMA code sets corresponding to one of said pair of orthogonal axes closest to said larger one of said magnitudes,

k) removing from further consideration the other of said first user or second user not related to said larger one of said magnitudes,

l) repeating step f) through step k) so as to identify another user closest to one of said pair of orthogonal axes until half of all users have been assigned to one of said two SCDMA code sets,

m) assigning all remaining users to the other one of said two SCDMA code sets.

5. The method as claimed in claim 2, wherein said determining steps further includes

f) providing an arbitrary pair of orthogonal axes, each of which corresponds to one of two SCDMA code sets,

g) normalizing a polarization vector of both said first user and said second user to unit length,

h) projecting a polarization vector of both said first user and said second user onto said pair of orthogonal axes,

i) calculating magnitudes of said polarization vectors,

j) identifying a larger one of said magnitudes,

k) assigning said first user or second user related to said larger one of said magnitudes to one of said two SCDMA code sets corresponding to one of said pair of orthogonal axes closest to said larger one of said magnitudes,

l) removing from further consideration the other of said first user or second user not related to said larger one of said magnitudes,

m) repeating step f) through step l) so as to identify another user closest to one of said pair of orthogonal axes until half of all users have been assigned to one of said two SCDMA code sets,

n) assigning all remaining users to the other one of said two SCDMA code sets.

6. The method as claimed in claim 2, wherein said determining steps further includes

f) normalizing a polarization vector of both said first user and said second user to unit length,

g) providing a pair of orthogonal axes defined by said polarization vectors of both said first user and said second user and orthonormal vectors corresponding to said polarization vectors, each said pair of orthogonal axes corresponding to one of two SCDMA code sets,

h) projecting a polarization vector of both said first user and said second user onto said pair of orthogonal axes,

i) calculating magnitudes of said polarization vectors,

j) identifying a larger one of said magnitudes,

k) assigning said first user or second user related to said larger one of said magnitudes to one of said two SCDMA code sets corresponding to one of said pair of orthogonal axes closest to said larger one of said magnitudes,

l) removing from further consideration the other of said first user or second user not related to said larger one of said magnitudes,

m) repeating step f) through step l) so as to identify another user closest to one of said pair of orthogonal axes until an optimum code set assignment that yields a lowest overall average interference per user is determined.

7. The method as claimed in claim 2, wherein said determining steps further includes

f) providing more than two substantially orthogonal axes, each of which corresponds to an SCDMA code set,

g) projecting a polarization vector of both said first user and said second user onto said more than two substantially orthogonal axes,

h) calculating magnitudes of said polarization vectors,

i) identifying a larger one of said magnitudes,

j) assigning said first user or second user related to said larger one of said magnitudes to one of said SCDMA code sets corresponding to one of said more than two substantially orthogonal axes closest to said larger one of said magnitudes,

k) removing from further consideration the other of said first user or second user not related to said larger one of said magnitudes,

l) repeating step f) through step k) so as to identify another user closest to one of said more than two substantially orthogonal axes until half of all users have been assigned to one of said SCDMA code sets,

m) assigning all remaining users to another one of said SCDMA code sets.

8. The method as claimed in claim 2, wherein said determining steps further includes

f) providing more than two substantially orthogonal axes, each of which corresponds to an SCDMA code set,

g) normalizing a polarization vector of both said first user and said second user to unit length,

h) projecting a polarization vector of both said first user and said second user onto said more than two substantially orthogonal axes,

i) calculating magnitudes of said polarization vectors,

j) identifying a larger one of said magnitudes,

k) assigning said first user or second user related to said larger one of said magnitudes to one of said SCDMA code sets corresponding to one of said more than two substantially orthogonal axes closest to said larger one of said magnitudes,

l) removing from further consideration the other of said first user or second user not related to said larger one of said magnitudes,

m) repeating step f) through step l) so as to identify another user closest to one of said pair of orthogonal axes until half of all users have been assigned to one of said SCDMA code sets,

n) assigning all remaining users to another one of said SCDMA code sets.

9. The method as claimed in claim 2, wherein said determining steps further includes

f) normalizing a polarization vector of both said first user and said second user to unit length,

g) providing more than two substantially orthogonal axes defined by said polarization vectors of both said first user and said second user and orthonormal vectors corresponding to said polarization vectors, each said more than two substantially orthogonal axes corresponding to an SCDMA code set,

h) projecting a polarization vector of both said first user and said second user onto said more than two substantially orthogonal axes,

i) calculating magnitudes of said polarization vectors,

j) identifying a larger one of said magnitudes,

k) assigning said first user or second user related to said larger one of said magnitudes to one of said SCDMA code sets corresponding to one of said more than two substantially orthogonal axes closest to said larger one of said magnitudes,

l) removing from further consideration the other of said first user or second user not related to said larger one of said magnitudes,

m) repeating step f) through step l) so as to identify another user closest to one of said more than two substantially orthogonal axes until an optimum code set assignment that yields a lowest overall average interference per user is determined.