Apparatus and method for managing channel resource
An apparatus for managing a channel resource by a node sets a channel hopping sequence and a channel hopping offset value which are to be used, divides an assigned time slot into a plurality of subslots, divides a data frame for transmission into a plurality of subframes, and selects a channel for transmitting the plurality of subframes in the plurality of subslots, respectively, by channel hopping based on the channel hopping sequence, the channel hopping offset value, the index of the time slot, and the index of a subslot for transmitting a subframe.
1. A method for managing a channel resource by a node in a wireless network, comprising:
assigning, by a channel resource management apparatus, a time slot;
dividing, by the channel resource management apparatus, the time slot into a plurality of subslots;
dividing, by the channel resource management apparatus, a data frame for transmitting to a target node into a plurality of subframes; and
selecting, by the channel resource management apparatus, a channel for transmitting the plurality of subframes in the plurality of subslots using a channel hopping sequence and a channel hopping offset value of the target node, respectively.
2. The method of claim 1 , wherein the selecting comprises estimating a channel for transmitting a corresponding subframe in a j-th subslot of an i-th time slot by the following Equation:
CH ( i,j )=the channel hopping sequence (( i+j+ the channel hopping offset value+sequence number of beacon frame) % number of physical frequency channels supported by a physical layer), wherein the % indicates a remaining modulus operator.
3. The method of claim 1 , further comprising receiving a beacon frame before assigning the time slot.
4. The method of claim 3 , further comprising setting the channel hopping sequence used for the wireless network and the channel hopping offset value, through the beacon frame.
5. The method of claim 3 , wherein the assigning comprises selecting a time slot among empty time slots through the beacon frame.
6. The method of claim 5 , wherein the selecting of a time slot comprises generating a random number having a selection probability that is one out of the number of empty slots and selecting a time slot among the empty time slots.
7. The method of claim 3 , wherein the assigning comprises selecting a time slot through time slot assignment negotiation with an upper-level node of the node.
8. The method of claim 1 , wherein the selecting comprises estimating transmission timing for transmitting the plurality of subframes.
9. The method of claim 8 , wherein the estimating of transmission timing is performed by using a transmission delay time, which is caused by backoff of CSMA/CA (carrier sense multiple access/collision avoidance).
10. The method of claim 8 , wherein the selecting comprises estimating a channel for transmitting a corresponding subframe in a j-th subslot of an i-th time slot by the following equation:
CH ( i,j )=the channel hopping sequence (( i+j+d+ the channel hopping offset value +sequence number of beacon frame) % number of physical frequency channels supported by a physical layer), wherein the % indicates a remaining modulus operator,
where d is a parameter value determined by the transmission delay time.
11. An apparatus for managing a channel resource to transmit a data frame in a wireless network, the apparatus comprising:
a setting unit that sets, via a terminal, a channel hopping sequence and a channel hopping offset value which are to be used;
a time slot assignment unit that assigns, via the terminal, a time slot;
a time slot and frame dividing unit that divides, via the terminal, the time slot into a plurality of subslots, and divides a data frame for transmitting to a target node into a plurality of subframes;
a channel selection unit that selects, via the terminal a channel for transmitting the plurality of subframes in the plurality of subslots using the channel hopping sequence and the channel hopping offset value of the target node, respectively, by using the channel hopping sequence, the channel hopping offset value, a first index of the time slot, and a second index of a subslot for transmitting a subframe.
12. The apparatus of claim 11 , wherein the channel selection unit selects a channel in a j-th subslot of an i-th time slot as CH(i,j) =channel hopping sequence ((i+j+ channel hopping offset value + sequence number of beacon frame) % number of physical frequency channels supported by a physical layer), wherein the % indicates a remaining modulus operator.
13. The apparatus of claim 11 , wherein the channel selection unit estimates a transmission timing for transmitting the plurality of subframes by using a transmission delay time, which is caused by backoff of CSMA/CA (carrier sense multiple access/collision avoidance).
14. The apparatus of claim 13 , wherein the channel selection unit selects a channel in a j-th subslot of an i-th time slot as CH(i,j) = the channel hopping sequence ((i+j+d+ the channel hopping offset value + sequence number of beacon frame) % number of physical frequency channels supported by a physical layer), wherein the % indicates a remaining modulus operator,
where d is a parameter value determined by the transmission delay time.
15. The apparatus of claim 11 , wherein the time slot assignment unit receives a beacon frame and selects a time slot among empty time slots.
16. The apparatus of claim 15 , wherein the time slot assignment unit selects a time slot among the empty slots by using a random number having a selection probability that is one out of the number of empty slots.
17. The apparatus of claim 11 , wherein the time slot assignment unit is assigned a time slot from an upper-level node through time slot assignment negotiation with the upper-level node.