Code allocation in CDMA

Claim 3

The method of claim 1, further comprising the steps of: (f) repeating steps (a) through (e) for at least one other tree-like structure; (g) comparing eligible spreading codes selected from the tree-like structures; and (h) selecting an eligible spreading code for allocation to the communication channel based on the comparison.

Claim 4

The method of claim 1, further comprising, when step (d) determines a lack of an eligible spreading code, the steps of: (i) determining whether a total free bandwidth of unallocated spreading codes is at least equal to the requested bandwidth; (j) if the total free bandwidth is less than the requested bandwidth, indicating that the requested bandwidth is not available; (k) if the total free bandwidth is at least equal to the requested bandwidth, selecting a spreading code allocated to another communication channel for re-allocation to the communication channel; and (l) allocating a new spreading code to the other communication channel.

Claim 5

The method of claim 1, wherein step (a) comprises setting the search level to the root of the tree-like structure.

Claim 6

The method of claim 1, wherein step (a) comprises setting the search level to a level of the tree-like structure corresponding to a maximum bandwidth allocable to a user of the communication system.

Claim 7

The method of claim 1, wherein step (c) comprises the step of selecting a first spreading code of two spreading codes at the next level of the tree-like structure based on the following criteria: the free bandwidth associated with the first spreading code is at least equal to a bandwidth parameter associated with the service request, and the free bandwidth associated with the first spreading code is less than the free bandwidth allocable to the other spreading code.

Claim 8

In a spread spectrum communication system that allocates bandwidth to connections using mutually orthogonal Walsh-Hadamard spreading code sequences logically representable by a tree-like data structure having levels indicative of communication channel bandwidths, a method of assigning a spreading code to a service request, comprising the steps of: (a) initiating a search for a spreading code at a selected level in the tree-like structure; and (b) if the bandwidth associated with the selected level is greater than the bandwidth parameter associated with the service request, iteratively performing the following steps: (1) selecting a first spreading code of two spreading codes at the next level of the tree-like structure based on the following criteria: the free bandwidth associated with the first spreading code is at least equal to a bandwidth parameter associated with the service request, and the free bandwidth associated with the first spreading code is less than the free bandwidth allocable to the other spreading code; and (2) if the free bandwidth associated with the first spreading code corresponds to a bandwidth parameter associated with the service request, allocating the first spreading code to the service request.

Claim 9

In a spread spectrum communication system that allocates bandwidth to connections using mutually orthogonal Walsh-Hadamard spreading code sequences logically representable by a tree-like data structure having levels indicative of communication channel bandwidths, a method of assigning a spreading code to a service request, comprising the steps of: (a) initiating a search for a spreading code at a selected level in the tree-like structure; and (b) if the bandwidth associated with the selected level is greater than the bandwidth parameter associated with the service request, iteratively performing the following steps: (1) selecting a first spreading code of two spreading codes at the next level of the tree-like structure based on the following criteria: the free bandwidth associated with the first spreading code is at least equal to a bandwidth parameter associated with the service request, and the free bandwidth associated with the first spreading code is less than the free bandwidth allocable to the other spreading code; and (2) if the free bandwidth associated with the first spreading code corresponds to a bandwidth parameter associated with the service request, allocating the first spreading code to the service request.

Claim 10

The method of claim 7, wherein the predetermined level corresponds to the root of the tree-like structure.

Claim 11

The method of claim 7, wherein the predetermined level corresponds to a maximum bandwidth parameter associated with the service request.

Claim 12

In a spread spectrum communication system that allocates bandwidth to connections using mutually orthogonal Walsh-Hadamard spreading code sequences logically representable by a tree-like data structure having levels indicative of communication channel bandwidths, a method of assigning a spreading code to a service request, comprising the steps of: (a) initiating a search for a spreading code at a level in the tree-like structure corresponding to a maximum allowable connection bandwidth; (b) if the bandwidth associated with the selected level is greater than the bandwidth parameter associated with the service request, recursively performing the following steps: (1) selecting a first spreading code of two spreading codes at the next level of the tree-like structure based on the following criteria: the free bandwidth associated with the first spreading code is at least equal to a bandwidth parameter associated with the service request, and the free bandwidth associated with the first spreading code is less than the free bandwidth allocable to the other spreading code; and (2) if the free bandwidth associated with the first spreading code corresponds to a bandwidth parameter associated with the service request, storing in a memory register the first spreading code and the free bandwidth in the sub-tree; and (c) repeating step (b) for each sub-tree having a root at a bandwidth corresponding to the maximum allowable bandwidth.

Claim 13

In a spread spectrum communication system that allocates bandwidth to connections using mutually orthogonal Walsh-Hadamard spreading code sequences logically representable by a tree-like data structure having levels indicative of communication channel bandwidths, a method of assigning a spreading code to a service request, comprising the steps of: (a) initiating a search for a spreading code at a level in the tree-like structure corresponding to a maximum allowable connection bandwidth; (b) if the bandwidth associated with the selected level is greater than the bandwidth parameter associated with the service request, recursively performing the following steps: (1) selecting a first spreading code of two spreading codes at the next level of the tree-like structure based on the following criteria: the free bandwidth associated with the first spreading code is at least equal to a bandwidth parameter associated with the service request, and the free bandwidth associated with the first spreading code is less than the free bandwidth allocable to the other spreading code; and (2) if the free bandwidth associated with the first spreading code corresponds to a bandwidth parameter associated with the service request, storing in a memory register the first spreading code and the free bandwidth in the sub-tree; and (c) repeating step (b) for each sub-tree having a root at a bandwidth corresponding to the maximum allowable bandwidth.

Claim 14

The method of claim 10, further comprising the steps of: (e) determining whether the total free bandwidth of the unallocated memory codes in the memory register is at least equal to the bandwidth parameter associated with the service request; (f) if the total free bandwidth of an unallocated memory code in the memory register is at least equal to the bandwidth parameter associated with the service request, allocating to the service request a spreading code from the memory register; and (g) if the total free bandwidth of the unallocated memory codes in the memory register is less than the bandwidth parameter associated with the service request, reallocating memory codes in the tree-like structure.

Claim 15

The method of claim 10, wherein step (d) comprises the step of allocating the service request to the spreading code associated with the minimum available bandwidth.

Claim 16

A base station in a spread spectrum communication system, comprising: a control and processing unit for controlling connections to a public switched telephone network; at least one traffic channel transceiver, a control channel transceiver, and a code generator, including a processor and associated memory for storing mutually orthogonal Walsh-Hadamard spreading code sequences logically representable by a tree-like data structure having levels indicative of communication channel bandwidths, wherein the code generator is operable to assign spreading codes to received service requests by recursively searching the tree-like data structure for a spreading code having free bandwidth that corresponds to a bandwidth parameter associated with a received service request and wherein the code generator assigns spreading codes to the received service requests by: (a) initiating a search for a spreading code at a level in the tree-like structure corresponding to a maximum allowable connection bandwidth; (b) if the bandwidth associated with the selected level is greater than the bandwidth parameter associated with the service request, recursively performing the following steps: (1) selecting a first spreading code of two spreading codes at the next level of the tree-like structure based on the following criteria: the free bandwidth associated with the first spreading code is at least equal to a bandwidth parameter associated with the service request, and the free bandwidth associated with the first spreading code is less than the free bandwidth allocable to the other spreading code; and (2) if the free bandwidth associated with the first spreading code corresponds to a bandwidth parameter associated with the service request, storing in a memory register the first spreading code and the free bandwidth in the sub-tree; and (c) repeating step (b) for each sub-tree having a root at a bandwidth corresponding to the maximum allowable bandwidth.

Claim 17

A base station in a spread spectrum communication system, comprising: a control and processing unit for controlling connections to a public switched telephone network; at least one traffic channel transceiver, a control channel transceiver, and a code generator, including a processor and associated memory for storing mutually orthogonal Walsh-Hadamard spreading code sequences logically representable by a tree-like data structure having levels indicative of communication channel bandwidths, wherein the code generator is operable to assign spreading codes to received service requests by recursively searching the tree-like data structure for a spreading code having free bandwidth that corresponds to a bandwidth parameter associated with a received service request and wherein the code generator assigns spreading codes to the received service requests by: (a) initiating a search for a spreading code at a level in the tree-like structure corresponding to a maximum allowable connection bandwidth; (b) if the bandwidth associated with the selected level is greater than the bandwidth parameter associated with the service request, recursively performing the following steps: (1) selecting a first spreading code of two spreading codes at the next level of the tree-like structure based on the following criteria: the free bandwidth associated with the first spreading code is at least equal to a bandwidth parameter associated with the service request, and the free bandwidth associated with the first spreading code is less than the free bandwidth allocable to the other spreading code; and (2) if the free bandwidth associated with the first spreading code corresponds to a bandwidth parameter associated with the service request, storing in a memory register the first spreading code and the free bandwidth in the sub-tree; and (c) repeating step (b) for each sub-tree having a root at a bandwidth corresponding to the maximum allowable bandwidth.