Primary channel selection method for relay networks

• US 9,622,086 B2
• Filed: 06/22/2015
• Issued: 04/11/2017
• Est. Priority Date: 06/22/2015
• Status: Expired due to Fees

• Current Assignee: King Fahd University Of Petroleum And Minerals
• Original Assignee: King Fahd University Of Petroleum And Minerals
• Inventors: Salhab, Anas (M. A.) Ata, Zummo, Salam Adel
• Primary Examiner(s): SHIVERS, ASHLEY L
• Application Number:
  US14/746,782
• Publication Number:
  US 20160374083A1
• Time in Patent Office: 659 Days
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 28/0252 per individual bearer or channel dynamic wireless traffic scheduling H04W72/12
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 72/12 Wireless traffic scheduling
• CPC Class Codes: H04W 84/047 using dedicated repeater stations
• CPC Class Codes: H04W 88/04 adapted for relaying to or from another terminal or user

Abstract

The primary channel selection method for relay networks functions in a relaying cognitive network where a number of relays are used to forward the source message to destination. The primary users utilize orthogonal spectrum bands. One primary user is selected among the available primary users in order to share its spectrum with the secondary users (source and relay). A certain amount of interference is allowed between the primary and secondary users when the primary users'"'"' channels are shared by the secondary users.

Claims

1. A primary channel selection method for relay networks, comprising the steps of:

selecting among available primary users one primary user receiver P_Sel whose channel results in a best performance for users of a secondary system;

sharing the one primary user receiver'"'"'s spectrum with secondary users (source and relay); and

restricting the sharing of the primary user receiver'"'"'s spectrum bands only to the secondary users;

wherein the spectrum bands of the primary user receivers are orthogonal and the best performance of the secondary system is achieved.

2. The primary channel selection method for relay networks according to claim 1, further comprising the steps of

a secondary user (SU) S establishing a S→

R_k link to K relays; and

the secondary user (SU) source S sending its message x to the K relays via the S→

R_k link under a transmit power constraint guaranteeing that interference with the selected PU receiver P_Sel does not exceed a threshold I_p.

3. The primary channel selection method for relay networks according to claim 2, further comprising the step of the secondary user (SU) source S calculating the transmit power constraint utilizing a formula characterized by the relation:

4. The primary channel selection method for relay networks according to claim 3, further comprising the steps of:

said multiple relays (R_k) establishing a R_k→

D link to a secondary destination D;

said multiple relays (R_k) establishing an interfering R_k→

P_k link to the k^th primary receiver P_k;

a primary transmitter P_Tx establishing an interfering link P_Tx→

D to the secondary destination D; and

each relay calculating a first hop SINR representing the received signal transmitted by S at the k^th relay said calculation being characterized by the relation;

γ

_S,k=√

{square root over (P_S)}h_S,kx₀+√

{square root over (P_p¹)}f_p,kx_p+n_k,

where γ

_S,k is the first hop SINR, h_S,k is the channel coefficient of the S→

R_k link, x₀ is the transmitted symbol from the SU source S with {|x₀|²}=P₀, f_p,k is the channel coefficient of the P_Tx→

R_k link, x_p is the transmitted symbol from the PU transmitter P_Tx with

5. The primary channel selection method for relay networks according to claim 4, further comprising the step of selecting active relays, said active relays being defined as the relays whose received signal is at least as strong as an outage threshold γ

_out;

wherein a signal-to-interference-plus-noise ratio (SINR) at the k^th relay is characterized by the relation;

6. The primary channel selection method for relay networks according to claim 5, further comprising the step of identifying a decoding set C_L of the active relays, said C_L being defined as the set of active relays that could have correctly decoded the source message upon initial establishment of the R_k→

D link and being characterized by the relation;

7. The primary channel selection method for relay networks according to claim 6, further comprising the step of said decoding set C_L of the active relays estimating channel coefficients g_l,m subject to the PU interference constraint and a transmit power at a relay R_l of the decoding set C_L, the R_l transmit power being characterized by the relation:

8. The primary channel selection method for relay networks according to claim 7, further comprising the steps of:

the secondary destination D calculating a maximum X_l,d based on a signal-plus-noise ratio (SINR) at the secondary destination D resulting from the l^th relay signal said SINR being characterized by the relation;

9. The primary channel selection method for relay networks according to claim 8, further comprising the step of said relay with the maximum X_l,d forwarding said message x from said SU source S to said secondary destination D.

10. The primary channel selection method for relay networks according to claim 9, further comprising the step of coordinating the training sequences transmitted by the relays to transmit in a time-division duplex manner.

11. A computer software product, comprising a non-transitory medium readable by a processor, the non-transitory medium having stored thereon a set of instructions for performing a primary channel selection method for relay networks, the set of instructions including:

(a) a first sequence of instructions which, when executed by the processor, causes said processor to select among available primary users one primary user receiver P_Sel whose channel results in a best performance for users of a secondary system;

(b) a second sequence of instructions which, when executed by the processor, causes said processor to share the one primary user receiver'"'"'s spectrum with secondary users (source and relay); and

(c) a third sequence of instructions which, when executed by the processor, causes said processor to restrict the sharing of the primary user receiver'"'"'s spectrum bands only to the secondary users;

wherein the spectrum bands of the primary user receivers are orthogonal and the best performance of the secondary system is achieved.

12. The computer software product according to claim 11, further comprising:

a fourth sequence of instructions which, when executed by the processor, causes said processor to utilize a secondary user (SU) S to establish a S→

R_k link to K relays; and

a fifth sequence of instructions which, when executed by the processor, causes said processor to utilize the secondary user (SU) source S to send its message x to the K relays via the S→

R_k link under a transmit power constraint which guarantees that interference with the selected PU receiver P_Sel does not exceed a threshold I_p.

13. The computer software product according to claim 12, further comprising:

a sixth sequence of instructions which, when executed by the processor, causes said processor to calculate the transmit power constraint for the secondary user (SU) source S utilizing a formula characterized by the relation;

14. The computer software product according to claim 13, further comprising:

a seventh sequence of instructions which, when executed by the processor, causes said processor to establish a R_k→

D link from said multiple relays (R_k) to a secondary destination D;

an eighth sequence of instructions which, when executed by the processor, causes said processor to establish an interfering R_k→

P_k link from said multiple relays (R_k) to the k^th primary receiver P_k;

a ninth sequence of instructions which, when executed by the processor, causes said processor to establish an interfering link P_Tx→

D from a primary transmitter P_Tx to the secondary destination D; and

a tenth sequence of instructions which, when executed by the processor, causes said processor to, for each relay, calculate a first hop SINR representing the received signal transmitted by S at the k^th relay said calculation being characterized by the relation;

γ

_S,k=√

{square root over (P_S)}h_S,kx₀+√

{square root over (P_p¹)}f_p,kx_p+n_k,

where γ

_S,k is the first hop SINR, h_S,k is the channel coefficient of the S→

R_k link, x₀ is the transmitted symbol from the SU source S with {|x₀|²}=P₀, f_p,k is the channel coefficient of the P_Tx→

R_k link, x_p is the transmitted symbol from the PU transmitter P_Tx with {|x_p|²}=P_p¹, where the superscript 1 is used to denote that this is the transmitted power at a first communication phase, n_k≈

(0, N₀) being noise in the communication links, {•

} denoting an expectation operation.

15. The computer software product according to claim 14, further comprising:

an eleventh sequence of instructions which, when executed by the processor, causes said processor to select active relays, said active relays being defined as the relays whose received signal is at least as strong as an outage threshold γ

_out; and

wherein a signal-to-interference-plus-noise ratio (SINR) at the k^th relay is characterized by the relation;

16. The computer software product according to claim 15, further comprising:

a twelfth sequence of instructions which, when executed by the processor, causes said processor to identify a decoding set C_L of the active relays, said C_L being defined as the set of active relays that could have correctly decoded the source message upon initial establishment of the R_k→

D link and being characterized by the relation;

17. The computer software product according to claim 16, further comprising:

a thirteenth sequence of instructions which, when executed by the processor, causes said processor to have said decoding set C_L of the active relays estimate g_l,m subject to the PU interference constraint and a transmit power at an at R_l of the decoding set C_L, the R_l transmit power being characterized by the relation;

18. The computer software product according to claim 17, further comprising:

a fifteenth sequence of instructions which, when executed by the processor, causes said processor to have the secondary destination D calculate a maximum X_l,d based on a signal-plus-noise ratio (SINR) at the secondary destination D resulting from the l^th relay signal said SINR being characterized by the relation;

19. The computer software product according to claim 18, further comprising a seventeenth sequence of instructions which, when executed by the processor, causes said processor to have said relay with the maximum X_l,d forward said message x from said SU source S to said secondary destination D.

20. The computer software product according to claim 19, further comprising an eighteenth sequence of instructions which, when executed by the processor, causes said processor to coordinate the training sequences transmitted by the relays to transmit in a time-division duplex manner.